JP6828567B2 - Grid interconnection system and power system - Google Patents

Description

The present disclosure relates to a grid-connected power system, and particularly to a power system having a plurality of power devices.

In recent years, power generation systems using renewable energy have become widespread. One example is a photovoltaic power generation system that uses sunlight. The photovoltaic power generation system is equipped with a solar cell and a power conditioner. The solar cell generates DC power, and the power conditioner converts this DC power into AC power. The converted AC power is supplied to the power system. Photovoltaic power generation systems range from small-scale ones for general households to large-scale ones such as mega solar systems.

Large-scale photovoltaic power generation systems are equipped with multiple power conditioners, each of which is connected to an electric power system. For example, the photovoltaic power generation system disclosed in Patent Document 1 includes a plurality of solar cells, a plurality of power conditioners, and a monitoring and control system. The monitoring and control system monitors and controls the plurality of power conditioners. Specifically, the monitoring and control system monitors input / output power, input / output voltage, input / output current, etc. of a plurality of power conditioners, and controls such as changing the output voltage.

Japanese Unexamined Patent Publication No. 2012-205322 Japanese Unexamined Patent Publication No. 2013-165544

Since the monitoring and control system as described above monitors and controls each power conditioner, the processing load inevitably increases as the number of power conditioners to be monitored and controlled increases. The high load problem of such a monitoring and control system is not limited to the photovoltaic power generation system, but also in other power generation systems in which a plurality of power devices (such as a power conditioner and a control device for controlling output power) are monitored by the monitoring control system. Also occurs.

The electric power system according to the present disclosure was created in view of the above circumstances. Therefore, an object thereof is to provide a grid interconnection system and an electric power system capable of reducing the processing load of an apparatus for monitoring a plurality of electric power devices.

The grid interconnection system provided by the first aspect of the present disclosure includes a power load, a plurality of power supply devices for supplying power to the power load, and a centralized management device for managing the plurality of power supply devices. It is a grid interconnection system in which electric power is supplied from an electric power system, and the centralized management device includes an alarm signal receiving means for receiving an alarm signal transmitted from a demand monitoring device, and an alarm signal receiving means according to the alarm signal. The target power setting means for setting the target power for reducing the power supplied from the power system, and the total output power and the target power so that the total output power of the plurality of power supply devices becomes the target power. Based on the above, the index calculating means for calculating the index for controlling the individual output power of each of the plurality of power supply devices and the index transmitting means for transmitting the index to each of the plurality of power supply devices are provided. Each of the plurality of power supply devices includes an index receiving means for receiving the index, a target power calculation means for calculating an individual target power of each power supply device based on an optimization problem using the index, and a target power calculation means. It is characterized by including a control means for controlling the individual output power of each power supply device so as to be the individual target power.

In a preferred embodiment of the grid interconnection system, the alarm signal is transmitted from the demand monitoring device based on a predicted demand value at the end of the current demand time period and a preset target demand value, and the target. The electric power is a target value for limiting the demand value of the demand time period to the target demand value or less.

In a preferred embodiment of the grid-connected system, the alarm signal is a multi-stage alarm signal, and at least one of the multi-stage alarm signals has the predicted demand value exceeding the target demand value. In this case, the demand monitoring device transmits the target power, and the target power is set stepwise according to the multi-step alarm signal.

In a preferred embodiment of the grid-connected system, the alarm signal is a regulated power that needs to be adjusted to bring the demand value at the end of the current demand time limit below a preset target demand value. Based on the above, the target power is transmitted from the demand monitoring device, and the target power is a target value for limiting the demand value of the demand time period to the target demand value or less.

In a preferred embodiment of the grid-connected system, each of the plurality of power supply devices is a storage battery power conditioner to which a storage battery is connected and supplies the power stored in the storage battery, and the storage battery power conditioner. Each of the above is further provided with a detection means for detecting the individual output power of each storage battery power conditioner and an individual output power transmission means for transmitting the detected individual output power. Individual output power receiving means for receiving the individual output power transmitted from each storage battery power conditioner, and total output power calculation for calculating the total of the individual output powers of the individual storage battery power conditioners as the total output power. It also has the means.

In a preferred embodiment of the grid-connected system, the centralized management device further includes mode setting means for setting a charging mode that allows charging of the storage battery, and the target power setting means is the charging. When the mode is set and the alarm signal is not received, the target power for charging the storage battery is set.

In a preferred embodiment of the grid interconnection system, a solar cell power conditioner to which a solar cell is connected is further provided, and the solar cell power conditioner uses the power generated by the solar cell as the power load. Supply.

The power system provided by the second aspect of the present disclosure includes the grid interconnection system provided by the first aspect and the demand monitoring device.

According to the grid interconnection system of the present disclosure, the centralized management device sets a target power according to an alarm signal received from the demand monitoring device so that the total output power of the plurality of power devices becomes the target power. , Calculate the index. Further, each of the plurality of power devices calculates an individual target power based on the index, and controls the individual output power based on the individual target power. As a result, the total output power becomes the target power. At this time, the centralized management device does not calculate the individual target power for each of the plurality of power devices, but only calculates the index. Therefore, the processing load of the centralized management device can be reduced.

It is a figure which shows the whole structure of the solar power generation system which concerns on 1st Embodiment. It is a figure which shows the functional structure about the output suppression control of the photovoltaic power generation system which concerns on 1st Embodiment. It is a figure which shows the model of the power conditioner assumed in the simulation. It is a figure which shows the step response of the power control system of the power conditioner assumed in the simulation. It is a figure which shows the verification result (case 1) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 2) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 3) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 4) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 5) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 6) by the simulation which concerns on 1st Embodiment. It is a figure which shows the verification result (case 7) by the simulation which concerns on 1st Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 2nd Embodiment. It is a figure which shows the functional structure about the output suppression control of the photovoltaic power generation system which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 1) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 2) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the verification result (case 3) by the simulation which concerns on 2nd Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 3rd Embodiment. It is a figure which shows the functional structure about the output suppression control of the photovoltaic power generation system which concerns on 3rd Embodiment. It is a figure which shows the functional structure about the peak cut control of the photovoltaic power generation system which concerns on 4th Embodiment. It is a figure which shows the functional structure about the reverse power flow avoidance control of the photovoltaic power generation system which concerns on 5th Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 6th Embodiment. It is a figure which shows the functional structure about the output suppression control of the photovoltaic power generation system which concerns on 6th Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 7th Embodiment. It is a figure which shows the functional structure about the output suppression control of the photovoltaic power generation system which concerns on 7th Embodiment. It is a figure which shows the functional structure about the schedule control of the photovoltaic power generation system which concerns on 8th Embodiment. It is a figure which shows the whole structure of the solar power generation system which concerns on 9th Embodiment. It is a figure which shows the functional structure about the demand monitoring device cooperation control of the solar power generation system which concerns on 9th Embodiment. It is a figure which shows the simulation result in the case where the demand monitoring device cooperation control is not performed, and the case where it is performed. It is a figure which shows the time change of the power consumption of the assumed power load and the power generation amount (total) of a solar cell in the simulation of FIG. 28.

Hereinafter, embodiments of the grid interconnection system and the electric power system of the present disclosure will be described. The electric power system includes a grid interconnection system interconnected to the electric power system, and the case where the grid interconnection system is a photovoltaic power generation system will be described as an example. In the following description, when the electric power at the interconnection point is positive, it is assumed that the electric power is output from the photovoltaic power generation system to the electric power system (reverse power flow). On the other hand, when the electric power at the interconnection point is a negative value, it is assumed that the electric power is output from the electric power system to the photovoltaic power generation system.

FIG. 1 shows the overall configuration of the photovoltaic power generation system PVS1 according to the first embodiment. As shown in the figure, the photovoltaic power generation system PVS1 includes a plurality of solar cells SP _i (i = 1,2, ..., n; n is a positive integer), a plurality of power conditioners PCS _i , It also has a centralized management device MC1. The photovoltaic power generation system PVS1 is a grid-connected reverse power flow system.

Each of the plurality of solar cells SP _i converts solar energy into electrical energy. Each solar cell SP _i is configured to include a plurality of solar cell panels connected in series or in parallel. The solar cell panel is, for example, a solar cell panel in which a plurality of solar cells made of a semiconductor such as silicon are connected and protected with a resin or tempered glass so that they can be used outdoors. The solar cell SP _i outputs the generated power (DC power) to the power conditioner PCS _i . The maximum amount of power that can be generated by the solar cell SP _i is defined as the power generation amount P _i ^SP of the solar cell SP _i .

Each of the plurality of power conditioners PCS _i converts the electric power (DC electric power) generated by the solar cell SP _i into AC electric power. Then, the converted AC power is output to the power system A. Each power conditioner PCS _i includes, for example, an inverter circuit, a transformer, and a control circuit. The inverter circuit converts the DC power input from the solar cell SP _i into AC power synchronized with the power system A. The transformer boosts (or steps down) the AC voltage output from the inverter circuit. The control circuit controls an inverter circuit or the like. Each power conditioner PCS _i controls the individual output power P _i ^out , which is the output power of its own device (power conditioner PCS _i ), by controlling an inverter circuit or the like. The power conditioner PCS _i is not limited to the one configured as described above.

When the effective power output from the power conditioner PCS _i P _i ^out, the reactive power and Q _i ^out, the complex power of P _i ^out + jQ _i ^out from the power conditioner PCS _i is outputted. Therefore, the complex power of Σ _i P _i ^out + j Σ _i Q _i ^out is output to the interconnection point between the plurality of power conditioners PCS _i and the power system A. That is, the power at the interconnection point is the sum of the output powers of each power conditioner PCS _i . The power at the interconnection point is defined as the interconnection point power P (t). In the present embodiment, the output control of the reactive power Q _i ^out , which is mainly used for suppressing the voltage fluctuation at the interconnection point, is not particularly considered. That is, the interconnection point power P (t) is the sum of the active power _Pi ^{out at} the interconnection point (Σ _{i Pi} ^out ). Thus, the individual output power each power conditioner PCS _i is controlled because it is active power P _i ^out, the individual output power and P _i ^out.

The centralized management device MC1 centrally manages a plurality of power conditioners PCS _i . The centralized management device MC1 transmits and receives various information to and from each power conditioner PCS _i by, for example, wireless communication. Note that wired communication may be used instead of wireless communication.

In the photovoltaic power generation system PVS1 configured in this way, the centralized management device MC1 monitors a predetermined adjustment target power, and is an adjustment target based on the adjustment target power and the target power which is the target value of the adjustment target power. Calculate the index to set the power to the target power. Then, this is transmitted to each power conditioner PCS _i . Each power conditioner PCS _i receives an index from the centralized management device MC1 and calculates an individual target power P _i ^ref , which is a target value of the individual output power P _i ^out , based on the received index. Then, the individual output power P _i ^out is controlled based on the calculated individual target power P _i ^ref . The index is information for the adjusted power to the target power, which is information for calculating the individual target power P _i ^ref.

In recent years, the number of photovoltaic power generation systems connected to the power system A has been increasing, and there is a possibility that the supply of power to the power system A will be excessive compared to the demand. In order to eliminate this oversupply condition, it is conceivable that the electric power company or the like instructs each photovoltaic power generation system to suppress the individual output power. At this time, each photovoltaic power generation system needs to suppress the output power according to this output suppression instruction. In the present embodiment, the output command value P ^C, which is the upper limit of the output power of the entire photovoltaic power generation system PVS1, is instructed as the output suppression instruction from the electric power company. Thus, solar systems PVS1, it is necessary to match the output power of the entire solar power system PVS1 the output command value P ^C.

Therefore, photovoltaic systems PVS1 according to this embodiment, the power conditioner PCS _i using the index distributed controls, consistent output power of the entire solar power system PVS1 the output command value P ^C I'm letting you. This is called "output suppression control". In the photovoltaic power generation system PVS1, all the individual output power P _i ^out of each power conditioner PCS _i is output to the interconnection point (power system A), so that the photovoltaic power generation system PVS1 has the interconnection point power P (power system A). The output suppression control is performed by regarding t) as the output power of the entire photovoltaic power generation system PVS1. That is, photovoltaic systems PVS1 is matched linking point power P (t) to the output command value P ^C. The index used in the output suppression control according to the present embodiment is defined as the suppression index pr. Specifically, in photovoltaic systems PVS1, the central control device MC1 monitors the interconnection point power P (t), based on the linking point power P (t) and the output command value P ^C, continuous calculating the suppression indication pr for system point power P (t) to the output command value P ^C. Then, this is transmitted to each power conditioner PCS _i . Each power conditioner PCS _i receives the suppression index pr from the centralized management device MC1, and calculates the individual target power P _i ^ref based on the received suppression index pr. Then, the individual output power P _i ^out is controlled based on the calculated individual target power P _i ^ref . Accordingly, it is made to coincide linking point power P (t) to the output command value P ^C. Thus, using the interconnection point power P (t) as the adjusted power is used the output command value P ^C as the target power.

FIG. 2 shows the functional configuration of the control system related to the output suppression control of the photovoltaic power generation system PVS1 shown in FIG. In FIG. 2, the illustration of the solar cell SP _i is omitted. As a control system related to the output suppression control, as shown in FIG. 2, each power conditioner PCS _i includes a receiving unit 11, a target power calculation unit 12, and an output control unit 13. Further, the centralized management device MC1 includes a target power setting unit 21, an interconnection point power detection unit 22, an index calculation unit 23, and a transmission unit 24.

The receiving unit 11 receives the suppression index pr transmitted from the centralized management device MC1. The receiving unit 11 receives the suppression index pr from the centralized management device MC1 by, for example, wireless communication. Note that wired communication may be used instead of wireless communication.

Target power calculation unit 12, based on the suppression indicators pr the receiving unit 11 has received, and calculates the individual target power P _i ^ref of the apparatus (power conditioner PCS _i). Specifically, the target power calculation unit 12, by solving a constrained optimization problem represented by the following equation (8), to calculate an individual target power P _i ^ref. In the equation (8), P _i ^lmt represents the rated output (output limit) of each power conditioner PCS _i , and w _i represents the weight of the power conditioner PCS _i regarding the suppression of active power. Weight w _i for this active power suppression is stored in the target power calculation unit 12. Further, the weight w _i regarding the active power suppression can be manually set by the user. Alternatively, each power conditioner PCS _i may be automatically set according to the conditions (temperature, climate, amount of ineffective power, etc.) of the power conditioner PCS _i . The details of the following equation (8) will be described later.

The output control unit 13 controls the inverter circuit to control the individual output power P _i ^out . The output control unit 13 sets the individual output power P _i ^out to the individual target power P _i ^ref calculated by the target power calculation unit 12.

The target power setting unit 21 sets a target value of the interconnection point power P (t). In the present embodiment, the target power setting unit 21 sets the target power in the output suppression control. Specifically, the target power setting unit 21 acquires the output command value P ^C commanded by the electric power company and sets the output command value P ^C as the target power. Target power setting unit 21 acquires, for example, the output command value P ^C from the power company through wireless communication. The output command value P ^C is not limited to the one obtained directly from the electric power company. For example, the administrator may manually input the output command value P ^C commanded by the electric power company to a predetermined computer, and the target power setting unit 21 may acquire the output command value P ^C from the computer. .. Alternatively, the configuration may be such that the output command value P ^C commanded by the electric power company is acquired by relaying another communication device. Target power setting unit 21 outputs target power set (the output command value P ^C) to the index calculation unit 23.

When there is no output suppression command from the electric power company, the target power setting unit 21 notifies the index calculation unit 23 that there is no command. “When there is no output suppression command from the electric power company” is when the output of the photovoltaic power generation system PVS1 can be output to the maximum without suppressing the output of the solar cell SP _i . For example, when each power conditioner PCS _i operates at the maximum power point by the maximum power point tracking control, the maximum output can be achieved. In the present embodiment, the target power setting unit 21 outputs a numerical value -1 to the index calculation unit 23 as the target power when there is no output suppression command from the electric power company. The method is not limited as long as it can be transmitted to the index calculation unit 23 that there is no command. For example, the target power setting unit 21 may acquire flag information indicating the presence / absence of an output suppression command from an electric power company or the like and transmit this to the index calculation unit 23. The flag information is, for example, "0" when there is no output suppression command, and "1" when there is an output suppression command. Note that if there is a command for output suppression (when the flag information is "1"), to obtain the output command value P ^C together with the flag information.

In the present embodiment, illustrating a case where the target power setting unit 21 obtains the output command value P ^C as an example, but is not limited thereto. Specifically, it is also possible to obtain information of an output inhibition rate [%] instead of the output command value P ^C. At this time, the target power setting unit 21 sets the acquired output suppression rate [%] and the rated output of the entire photovoltaic power generation system PVS1 (that is, the total rated output of each power conditioner PCS _i ) Σ _i P _i ^lmt . based calculates the output command value P ^C. For example, the target power setting unit 21, when acquiring the command is 20% as an output inhibition rate, 80% of the rated output sigma _i P _i ^lmt photovoltaic systems PVS1 (= 100-20) the output command value P Calculate as ^C. Then, the calculated output command value P ^C is output to the index calculation unit 23 as the target power.

The interconnection point power detection unit 22 detects the interconnection point power P (t). Then, the detected interconnection point power P (t) is output to the index calculation unit 23. The interconnection point power detection unit 22 may be configured as a detection device different from the centralized management device MC1. In this case, the detection device (interconnection point power detection unit 22) transmits the detection value of the interconnection point power P (t) to the centralized management device MC1 by wireless communication or wired communication.

The index calculation unit 23 calculates an index for setting the interconnection point power P (t) as the target power. In the present embodiment, since the output command value P ^C as the target power is inputted, the index calculation unit 23 calculates the suppression indicators pr for interconnection point power P (t) to the output command value P ^C .. The index calculation unit 23 calculates the suppression index pr based on the following equations (9) and (10), where the Lagrange multiplier is λ, the gradient coefficient is ε, and the time is t. However, the index calculation unit 23 as an output command value P ^C, when it is entered the numerical value -1 to indicate that there is no command output suppression from power company, the Lagrange multiplier λ is set to "0". That is, the suppression index pr is calculated as "0". In the following equation (9), since the individual output power P _i ^out and the output command value P ^C are values that change with time t, the individual output power is P _i ^out (t) and the output command value, respectively. Is described as ^PC (t). Details of the following equations (9) and (10) will be described later.

The transmission unit 24 transmits the suppression index pr calculated by the index calculation unit 23 to each power conditioner PCS _i .

Then, the output suppression control photovoltaic system PVS1 performed, power and why conditioners for calculation of individual target power P _i ^ref according conditioner PCS _i equation (8) is used, the suppression indicators pr by the central control device MC1 The reason why the above equation (9) and the above equation (10) are used for the calculation will be described.

The photovoltaic power generation system PVS1 is configured to achieve the following three goals in output suppression control. The first goal (goal 1-1) is that "each power conditioner PCS _i calculates the individual target power in a distributed manner". The second goal (Goal 1-2) is to "match the output power (coupling point power) at the interconnection point of the photovoltaic power generation system PVS1 with the output command value (target power) from the electric power company". is there. The third goal (goal 1-3) is "to enable the output suppression amount to be adjusted for each power conditioner PCS _i ". The output suppression amount is the difference between the maximum power value that can be output by the power conditioner PCS _i and the individual output power P _i ^out . The maximum power value that can be the output, when the power generation amount P _i ^SP> rated output P _i ^lmt solar cell SP _i is the rated output P _i ^lmt power conditioner PCS _i. On the other hand, when the power generation amount P _i ^SP of the solar cell SP _i ≤ the rated output P _i ^lmt , the power generation amount P _i ^SP of the solar cell SP _i .

First, the central control device MC1 is, consider the constrained optimization problem when intensive determining the single target power P _i ^ref. Then, the following equation (11) is obtained. Here, as described above, P _i ^ref represents the individual target power of each power conditioner PCS _i , P _i ^lmt represents the rated output (output limit) of each power conditioner PCS _i , and P ^C is , Represents the output command value commanded by the electric power company. ^Let (P _i ^ref ) ^* be the individual target power P _i ^ref , which is the optimum solution of the following equation (11). In the following equations (11), the equation (11a) is the minimization of the output suppression amount of the individual output power P _i ^out , the equation (11b) is the constraint by the rated output P _i ^lmt , and the equation (11c) is the interconnection point. it represents respectively to match the power P (t) to the output command value P ^C.

This shows the case where the centralized management device MC1 obtains the individual target power (P _i ^ref ) ^* from the above equation (11). Therefore, in the case of the above equation (11), since each power conditioner PCS _i does not calculate the individual target power (P _i ^ref ) ^* in a distributed manner, the target 1-1 is not achieved.

Next, consider a constrained optimization problem when each power conditioner PCS _i obtains an individual target power P _i ^ref in a distributed manner. Then, the following equation (12) is obtained.

However, the individual target power is the optimum solution of equation (12) is the power conditioner PCS _i is the individual target power P _i ^ref obtained dispersion, the above-mentioned (11c) below are not considered. Thus, unable to achieve the target 1-2 to match the interconnection point power P (t) to the output command value P ^C from the power company.

Therefore, consider achieving Goal 1-2 by the following method. That is, each power conditioner PCS _i calculates the individual target power P _i ^ref in a distributed manner based on the suppression index pr received from the centralized management device MC1. As a result, Goal 1-2 is achieved. The constrained optimization problem when each power conditioner PCS _i obtains the individual target power P _i ^ref in a distributed manner using the suppression index pr can be expressed by the above equation (8). The individual target power P _i ^ref , which is the optimum solution of the above equation (8), is set to (P _i ^ref ) ^♭ .

Here, when the optimum solution (P _i ^ref ) ^* obtained by the above equation (11) and the optimum solution (P _i ^ref ) ^♭ obtained by the above equation (8) match, the interconnection point power P ( t) it is possible to match the output command value P ^C from the power company. That is, even when each power conditioner PCS _i solves the optimization problem in a distributed manner, the target 1-2 can be achieved. Therefore, paying attention to the optimality of the steady state, consider the suppression index pr such that (P _i ^ref ) ^* = (P _i ^ref ) ^♭ . Therefore, the KKT (Karush-Kuhn-Tucker) conditions of the above equations (11) and (8) are considered. As a result, the following equation (13) can be obtained from the KKT condition of the above equation (11), and the following equation (14) can be obtained from the KKT condition of the above equation (8). In addition, μ is a predetermined Lagrange multiplier.

From the above equations (13) and (14), by setting pr = λ (the above equation (10)), the two optimal solutions (P _i ^ref ) ^* and (P _i ^ref ) ^♭ match. I understand. Therefore, the centralized management device MC1 calculates the Lagrange multiplier λ and presents (transmits) the calculated Lagrange multiplier λ to each power conditioner PCS _i as the suppression index pr, so that each power conditioner PCS _i is described above. The individual target power (P _i ^ref ) ^♭ can be calculated from Eq. (8). As a result, even when each power conditioner PCS _i obtains the individual target power P _i ^ref in a distributed manner, the interconnection point power P (t) and the output command value P ^C from the power company are matched. be able to. That is, the goal 1-2 can be achieved.

Subsequently, a method of calculating the Lagrange multiplier λ by the centralized management device MC1 will be described. To the central control device MC1 seeks Lagrangian multiplier lambda, _{firstly, h 1, i = -P i} ref, and ^{_{h 2, i = P i ref}} -P i lmt, collectively inequality constraints of the power conditioner PCS _i Let h _{j, i} (j = 1, 2, i = 1, ..., N). Then, consider the following equation (15), which is the dual problem of the above equation (11).

Here, assuming that the optimum solution (P _i ^ref ) ^♭ obtained by each power conditioner PCS _i is determined, the following equation (16) is obtained, which is a form of the maximization problem for the Lagrange multiplier λ. When the gradient method is applied to the following equation (16), the following equation (17) is obtained. Note that ε represents the gradient coefficient and τ represents the time variable.

In the above equation (17), (P _i ^ref ) ^♭ is replaced with the individual output power P _i ^out of each corresponding power conditioner PCS _i . Further, the centralized management device MC1 does not individually observe the individual output power P _i ^out of each power conditioner PCS _i , but observes the interconnection point power P (t) = Σ _i P _i ^out . Further, it is assumed that the sequential output command value P ^C is acquired from the electric power company. Then, the above equation (9) is obtained. Thus, the central control device MC1, based on the interconnection point power P (t) and the output command value P ^C from the power company may calculate the Lagrange multiplier lambda. Then, the Lagrange multiplier λ calculated based on the above equation (10) is used as the suppression index pr.

From the above, in the present embodiment, the power conditioner PCS _i, when calculating the individual target power P _i ^ref, and using an optimization problem shown in equation (8). Further, the centralized management device MC1 uses the above equations (9) and (10) for calculating the suppression index pr.

Next, in the photovoltaic power generation system PVS1 configured as described above, it was verified by simulation that the above three goals were achieved and the system was operating properly.

In the simulation, a photovoltaic power generation system PVS1 having ₁₀ power conditioners PCS _i (i = 1 to 10; PCS _{1 to} PCS ₁₀ ) was assumed.

The model of the power system A (interconnection point voltage) is the following equation (18). In the following equation (18), R = R _L × _L, a _{X = X L × L, R} L is the resistance component per unit length of the distribution line, X _L is the reactance component per unit length of the distribution lines , L represents the length of the distribution line, and V ₁ represents the upper system voltage. In this simulation, the upper system voltage V ₁ is 6600 [V], the resistance component _RL per unit length of the wiring line is 0.220 [Ω / km], and the reactance component X _L per unit length of the distribution line. Was 0.276 [Ω / km], and the length L of the distribution line was 5 [km].

The power conditioner PCS _i is assumed to be the model shown in FIG. 3, and PI control is performed in order to control the individual output power P _i ^out to the individual target power P _i ^ref . The current control system of the power conditioner PCS _i is designed to respond much faster than the effective / reactive power control system. Here, assuming that an appropriate control system has been designed in advance, it is realized by a first-order lag system with K = 1 and T = 10 ^-4 . The power control system, which is the upper control system of the current control system, assumes a time constant such that the step response converges within 1 [s], and K _PP = K _PQ = 1.0 × 10 ^-7 , K _IP = K _IQ = 1.2 × 10 ^-3 . K _PP represents the proportional gain of active power, K _PQ represents the proportional gain of reactive power, K _IP represents the integrated gain of active power, and K _IQ represents the integrated gain of reactive power. FIG. 4 shows the step response of the active / reactive power control system.

5 to 11 show the results when the simulation was performed under a plurality of conditions using the photovoltaic power generation system PVS1 of the model shown above. When the power generation amount P _i ^SP of the connected solar cell SP _i is larger than the rated output P _i ^lmt , each power conditioner PCS _i is suppressed to the rated output P _i ^lmt of the power conditioner PCS _i. And.

As case 1, a simulation was performed in which ₁₀ power conditioners PCS _{1 to} PCS ₁₀ all had the same conditions. Let the simulation be simulation 1-1. In simulation 1-1, all ₁₀ power conditioners PCS _{1 to} PCS ₁₀ have a rated output P _i ^lmt of 500 [kW], a weight w _i related to active power suppression of 1.0, and a power generation amount of the solar cell SP _i . P _i ^SP has to be 600 [kW]. Further, the output command value P ^C from the electric power company is assumed to be 3000 [kW] when 0 ≦ t <60 [s] and no command when 60 ≦ t [s]. When "there is no command of the output command value P ^C ", the numerical value -1 indicating that there is no command is used as the output command value P ^C as described above. Other, gradient coefficients epsilon 0.025, and each sampling time and update the central control device MC1 individual target power update and the power conditioner PCS _i suppression indicators pr is performed to carry out P _i ^ref and 1 [s] .. Further, it is assumed that all the power conditioners PCS _i are operated at a power factor of 1 (reactive power target value = 0 [kvar]). FIG. 5 shows the simulation results in simulation 1-1.

FIGS. 5 (a) to 5 (e) show the amount of power generated by the solar cell SP _i of each power conditioner PCS _i P _i ^SP (dashed line), rated output P _i ^lmt (solid line), and individual target power P _i ^ref ( (Dashed line) and individual output power P _i ^out (solid line) are shown. 5 (a) is, for the power conditioner PCS _1, PCS _2, FIG. 5 (b), the power conditioner PCS _3, PCS _4, FIG. 5 (c), the power conditioner PCS _5, PCS ₆ 5 (d) shows the power conditioners PCS ₇ and ₈ and FIG. 5 (e) shows the power conditioners PCS ₉ and PCS ₁₀ . Incidentally, in FIG. 5 (a) ~ (e) , for convenience of understanding, been described in slightly shifted upward to separate target power P _i ^ref (dashed line). FIG. 5F shows the individual output powers P ₁ ^{out to} P ₁₀ ^out of each of the power conditioners PCS _{1 to} PC ₁₀ in one graph. FIG. 5 (g) illustrates the interconnection point power P (t) output command value from the (solid line) and electric power company P ^C (dashed line). Incidentally, in FIG. 5 (g), the convenience of understanding, if there is no command output command value P ^C, outputs command the sum of the rated output P ₁ ^lmt ~P ₁₀ ^lmt of PCS ₁ ~PCS ₁₀ of the power conditioner It is described as the value P ^C. FIG. 5 (h) shows the Lagrange multiplier λ calculated by the index calculation unit 23. Then, FIG. 5 (i) shows the suppression index pr calculated by the index calculation unit 23.

The following can be confirmed from FIG. That is, in the period from the start of the simulation to the issuance of the output suppression command (0 ≦ t <60 [s]), as shown in FIGS. 5A to 5E, the individual power conditioners PCS _{1 to} PCS ₁₀ are individually used. The output power P ₁ ^{out to} P ₁₀ ^out increases according to the amount of power generated by the solar cell SP _i P ₁ ^{SP to} P ₁₀ ^SP until it reaches the individual target power P ₁ ^{ref to} P ₁₀ ^ref of 500 [kW]. There is. Then, when the individual target powers P ₁ ^{ref to} P ₁₀ ^ref reach 500 [kW], the individual output powers P ₁ ^{out to} P ₁₀ ^out thereafter become 500 [kW] of the individual target powers P ₁ ^{ref to} P ₁₀ ^ref. ] Can be confirmed to be controlled. Moreover, the post command output command value ^{P C (60 ≦ t [s} ]), as shown in FIG. 5 (h) and FIG. 5 (i), be the Lagrange multiplier λ and inhibition index pr is updated You can check. Each power conditioner PCS ₁ ~PCS _10, based on the update of the suppression indicators pr, as shown in FIG. 5 (a) ~ (e) , by changing the individual target power P ₁ ^ref ~P ₁₀ ^ref There is. Therefore, it can be confirmed that the individual output powers P ₁ ^{out to} P ₁₀ ^out are suppressed and follow the individual target powers P ₁ ^{ref to} P ₁₀ ^ref . Thus, as shown in FIG. 5 (g), the suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state.

As case 2, the weights w ₅ and w ₆ related to the active power suppression set in the power conditioners PCS ₅ and PCS ₆ out of the ₁₀ power conditioners PCS _{1 to} PCS ₁₀ are the other power conditioners PCS _1. We simulated the cases different from those of ~ PCS ₄ and PCS ₇ ~ PCS ₁₀ . Let the simulation be simulation 1-2. In simulation 1-2, the weight w _i for the active power suppression of the two power conditioners PCS ₅ and PCS ₆ was set to 2.0. Other conditions are the same as in Simulation 1-1. FIG. 6 shows the simulation results in simulation 1-2. 6 (a) to 6 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 6 (a) ~ (e) , compared with the simulation 1-1 shown in FIG. 5, the output suppression quantity of the power conditioner PCS _5, PCS ₆ for changing the weight w _i of the effectiveness power throttle However, it can be confirmed that the output suppression amount of other power conditioners PCS _{1 to} PCS ₄ and PCS _{7 to} PCS ₁₀ is half. At this time, as shown in FIGS. 6 (h) and 6 (i), the Lagrange multiplier λ and the suppression index pr calculated by the centralized management device MC1 are also the values in the above simulation 1-1 (FIGS. 5 (h) and 5). It can also be confirmed that it is different from (i)). Therefore, by adjusting the weights w _i relating active power suppression, it is possible to have a difference in output suppression quantity. Further, as shown in FIG. 6, the output suppression amount of the other power conditioners PCS _{1 to} PCS ₄ and PCS _{7 to} PCS ₁₀ is measured by the reduction of the output suppression amount of the power conditioners PCS ₅ and PCS _{6 in} the above simulation 1. by greater than -1, as shown in FIG. 6 (g), interconnection point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is operating appropriately in consideration of the weight w _i regarding the active power suppression set in the power conditioner PCS _i .

As case 3, a simulation was performed in which the weights w ₅ and w ₆ related to the active power suppression of two power conditioners PCS ₅ and PCS ₆ out of ₁₀ power conditioners PCS _{1 to} PCS 10 were changed in the middle. .. Let the simulation be simulation 1-3. In simulation 1-3, the weights w ₅ and w ₆ related to the active power suppression of the two power conditioners PCS ₅ and PCS ₆ are set to w ₅ = w ₆ = 1.0 at the start time (0 [s]). After 120 [s] elapsed, the change was made to w ₅ = w ₆ = 2.0. That is, in 60 ≦ t <120 [s] , while the weight w ₁ to w ₁₀ about the effective suppression of power each power conditioner PCS ₁ ~PCS ₁₀ as described above simulation 1-1 are all 1.0, 120 In ≦ t [s], the weights w ₅ and w ₆ related to the active power suppression of the power conditioners PCS ₅ and PCS ₆ were changed to 2.0 as in the above simulation 1-2. Other conditions are the same as in Simulation 1-1. FIG. 7 shows the simulation results in Simulation 1-3. 7 (a) to 7 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, before changing the weights w ₅ and w ₆ related to the active power suppression of the power conditioners PCS ₅ and PC ₆ to 2.0 (60 ≦ t <120 [s]), the same result as the above simulation 1-1 is obtained. Yes, after changing the weights w ₅ and w ₆ related to the active power suppression of the power conditioners PCS ₅ and PC ₆ to 2.0 (120 ≦ t [s]), the same result as the above simulation 1-2 is obtained. It can be confirmed that Therefore, even in this way adjust the weights w _i relating active power suppression in the middle (change), continuously, it is possible to match the interconnection point power P (t) to the output command value P ^C.

In case 4, the power generation of the solar cell SP _{i is performed} for each of the two power conditioners (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS ₁₀ ). The case where the quantity P _i ^SP was different was simulated. Let the simulation be simulation 1-4. In Simulation 1-4, of the solar cell SP _i for each of the two power conditioners (PCS ₁ and PCS ₂ , PCS ₃ and PCS ₄ , PCS ₅ and PCS ₆ , PCS ₇ and PCS ₈ , PCS ₉ and PCS ₁₀ ). The amount of power generated P _i ^SP is P ₁ ^SP , P ₂ ^SP = 600 [kW], P ₃ ^SP , P ₄ ^SP = 500 [kW], P ₅ ^SP , P ₆ ^SP = 400 [kW], P ₇ ^{SP, respectively.} , P ₈ ^SP = 300 [kW], P ₉ ^SP , P ₁₀ ^SP = 200 [kW]. Other conditions are the same as in Simulation 1-1. FIG. 8 shows the simulation results in Simulation 1-4. 8 (a) to 8 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 8 (a) ~ (e) , if the individual target power P _i ^ref is power generation amount P _i ^SP or more solar cells SP _i, it can be confirmed that not performing the output suppression. Further, as shown in FIG. 8 (f), if the same power conditioner PCS ₁ ~PCS ₁₀ rated output P _i ^lmt power generation amount P _i ^SP solar cell SP _i different, the amount of power generated by solar cell SP _i P _i ^SP with less power conditioner PCS ₇ ~PCS ₁₀ it can be confirmed that that has not been output suppression. Furthermore, as shown in FIG. 8 (g), the suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is operating appropriately in consideration of the power generation amount P _i ^SP of the solar cell SP _i .

As a case 5, every two of the power conditioner (PCS ₁ and PCS _2, PCS ₃ and PCS _4, PCS ₅ and PCS _6, PCS ₇ and PCS _8, PCS ₉ and PCS _10), the rated output P _i ^lmt Different cases were simulated. Let the simulation be simulation 1-5. In the simulation 1-5, the rated output P _i ^lmt every two of the power conditioner (PCS ₁ and PCS _2, PCS ₃ and PCS _4, PCS ₅ and PCS _6, PCS ₇ and PCS _8, PCS ₉ and PCS ₁₀₎ P ₁ ^lmt , P ₂ ^lmt = 500 [kW], P ₃ ^lmt , P ₄ ^lmt = 400 [kW], P ₅ ^lmt , P ₆ ^lmt = 300 [kW], P ₇ ^lmt , P ₈ ^lmt = It was set to 200 [kW], P ₉ ^lmt , and P ₁₀ ^lmt = 100 [kW]. Further, as the output command value P ^C from the electric power company, there is no command when 0 ≦ t <60 [s], and 2000 [kW] when 60 ≦ t [s], and the power generation amount P _i ^SP of the solar cell SP _i is set. The rated output was set to P _i ^lmt +100 [kW], respectively. Other conditions are the same as in Simulation 1-1. FIG. 9 shows the simulation results in Simulation 1-5. Note that FIGS. 9 (a) to 9 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 9 (f), the case where the rated output P _i ^lmt is different, the output suppression amount can be confirmed to be equal in each of the power conditioner PCS ₁ ~PCS _10. Further, the interconnection point power P (t) is suppressed as shown in FIG. 9 (g), the can be confirmed that matches the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS1 is operating appropriately in consideration of the rated output P _i ^lmt of the power conditioner PCS _i .

As case 6, a case where the sampling time was lengthened was simulated. Let the simulation be simulation 1-6. In simulation 1-6, the sampling time was set to 60 [s] = 1 [min]. Further, the slope coefficient ε and 0.0005, as the output command value P ^C from the power company, 0 ≦ t <5 [min ] no instruction in, and a 5 ≦ t [min] In 3000 [kW]. Other conditions are the same as in Simulation 1-1. FIG. 10 shows the simulation results in Simulation 1-6. It should be noted that FIGS. 10 (a) to 10 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 10 (g), when longer the sampling time, although the time to interconnection point power P (t) follows the output command value P ^C is longer than the above-described simulation 1-1 , is suppressed linking point power P (t) is, it can be confirmed that they match the output command value P ^C in the steady state.

In case 7, a simulation was performed in which the sampling time was made longer than the sampling time in case 6. Let the simulation be simulation 1-7. In simulation 1-7, the sampling time was set to 180 [s] = 3 [min]. Further, the slope coefficient ε and 0.0003, as the output command value P ^C from the power company, 0 ≦ t <5 [min ] no instruction in, and a 5 ≦ t [min] In 3000 [kW]. Other conditions are the same as in Simulation 1-1. FIG. 11 shows the simulation results in Simulation 1-7. 11 (a) to 11 (i) are diagrams corresponding to FIGS. 5 (a) to 5 (i) in the simulation 1-1, respectively.

The following can be confirmed from FIG. That is, as shown in FIG. 11 (g), in the case where the sampling time was longer than the simulation 1-6 also are interconnection point power P (t) is suppressed, one to the output command value P ^C in a steady state You can confirm that you are doing it.

The following can be confirmed by comparing FIGS. 5 to 11 in addition to the results for each of FIGS. 5 to 11. That is, as shown in each figure (h) and (i), the Lagrange multiplier λ and suppression indicator pr is the power conditioner PCS ₁ ~PCS _10, power generation of the solar cell SP _i P _i ^SP, the rated output P _i ^lmt, weight w _i relating active power suppression, and, on the basis of such an output command value P ^C, it can be confirmed that different values are calculated. Further, as shown in each figure (a) ~ (e), in accordance with the updating of the suppression indicators pr, it can be confirmed that the individual target power P _i ^ref is updated. The power conditioner PCS ₁ ~PCS _10, in response to the individual target power P _i ^ref, and controls the individual output power P _i ^out. Thus, as shown in (g) is each figure, it can be confirmed that by matching linking point power P (t) to the output command value P ^C. From the above, it can be said that the suppression index pr calculated by the centralized management device MC1 using the above equations (9) and (10) is an appropriate value.

From the results of the above simulations 1-1 to 1-7, in the photovoltaic power generation system PVS1, each power conditioner PCS _i distributes the individual target power P based on the suppression index pr received from the centralized management device MC1. _i ^ref is calculated. Therefore, the above target 1-1 has been achieved. Further, the interconnection point power P (t) is suppressed, coincides with the output command value P ^C. Therefore, the above target 1-2 has been achieved. Then, the individual output power P _i ^out changes for each power conditioner PCS _i according to various conditions. That is, the output suppression amount changes for each power conditioner PCS _i according to various conditions. Therefore, the above goals 1-3 have been achieved. From the above, it can be seen that the photovoltaic power generation system PVS1 has achieved the above three goals.

As described above, in the photovoltaic power generation system PVS1 according to the first embodiment, the central control device MC1 is outputted from the command value P ^C and detected interconnection point power P (t) from the power company, the ( The suppression index pr is calculated using the equation 9) and the above equation (10), and this is transmitted to each power conditioner PCS _i . Further, each power conditioner PCS _i calculates the individual target power P _i ^ref by solving the optimization problem of the above equation (8) in a distributed manner based on the received suppression index pr, and then ^obtains the individual output power. P _i ^out is controlled to the individual target power P _i ^ref . As a result, the centralized management device MC1 can perform only the simple calculations shown in the above equations (9) and (10). Therefore, in the photovoltaic power generation system PVS1, the processing load of the centralized management device MC1 can be reduced. Further, even when each power conditioner PCS _i calculates the individual target power P _i ^ref in a distributed manner based on the suppression index pr and controls the individual output power P _i ^out , the interconnection point power P (t). ) it can be matched to the output command value P ^C from the power company. That is, the photovoltaic power generation system PVS1 can match the interconnection point power P (t) with the target power.

Next, the photovoltaic power generation system PVS2 according to the second embodiment will be described. The same or similar to the photovoltaic power generation system PVS1 according to the first embodiment is designated by the same reference numerals and the description thereof will be omitted. FIG. 12 shows the overall configuration of the photovoltaic power generation system PVS2. As shown in FIG. 12, the photovoltaic power generation system PVS2 includes a plurality of solar cells SP _i (i = 1, 2, ..., N; n is a positive integer), a plurality of power conditioners PCS _PVi , and the like. It is composed of a plurality of storage batteries B _k (k = 1, 2, ..., M; m is a positive integer), a plurality of power conditioners PCS _Bk , and a centralized management device MC2. The photovoltaic power generation system PVS2 is a grid-connected reverse power flow system.

In the photovoltaic power generation system PVS1 according to the first embodiment, the case where the photovoltaic power generation system PVS1 is composed of a plurality of power conditioners PCS _i connected to the solar cell SP _i has been described as an example. However, in the case of such a photovoltaic power generation system PVS1, the influence on the output due to the weather fluctuation is large. Therefore, photovoltaic systems PVS2, in order to suppress the output variation due to the weather change, as compared with the solar power generation system PVS1, further comprising a power conditioner PCS _Bk connected to battery B _k.

Each of the plurality of power conditioner PCS _PVi is configured in the same manner as the power conditioner PCS _i of the first embodiment. That is, each power conditioner PCS _PVi converts the power generated by the solar cell SP _i (DC power) into AC power, and outputs the converted AC power to the power system A.

Each of the plurality of storage batteries B _k is a battery that can store electric power by repeatedly charging. The storage battery B _k is, for example, a secondary battery such as a lithium ion battery, a nickel hydrogen battery, a nickel cadmium battery, or a lead storage battery. Further, a capacitor such as an electric double layer capacitor may be used. Battery B _k is to discharge accumulated power and supplies DC power to the power conditioner PCS _Bk.

Each plurality is the power conditioner PCS _Bk, is intended for converting the DC power supplied from battery B _k to AC power. Further, each power conditioner PCS _Bk converts AC power input from the power system A and each power conditioner PCS _PVi into DC power and supplies it to the storage battery B _k . That is, the storage battery B _k is charged. Each power conditioner PCS _Bk is controlling the charging and discharging of the battery B _k. Thus, functions as a discharge circuit to discharge the charging circuit and the battery B _k to charge the battery B _k.

_Assuming that the active power output from each power conditioner PCS _PVi is P _PVi ^out and the ineffective power is Q _PVi ^out , the complex power of P _PVi ^out + jQ _PVi ^out is output from each power conditioner PCS _PVi . Further, assuming that the active power output from each power conditioner PCS _Bk is P _Bk ^out and the ineffective power is Q _Bk ^out , the complex power of P _Bk ^out + jQ _Bk ^out is output from each power conditioner PCS _Bk . Therefore, at the interconnection point between the multiple power conditioners PCS _PVi and PCS _Bk and the power system A, (Σ _i P _PVi ^out + Σ _k P _Bk ^out ) + j (Σ _i Q _PVi ^out + Σ _k Q _Bk ^out ) Complex power is output. That is, the interconnection point power P (t) is the sum of the output powers of the power conditioners PCS _PVi and PCS _Bk . Also in this embodiment, the output control of the reactive powers Q _PVi ^out and Q _Bk ^out , which are mainly used for suppressing voltage fluctuations at the interconnection point, is not particularly considered. That is, the interconnection point power P (t) is the sum of the active powers P _PVi ^out and P _Bk ^{out at} the interconnection point (Σ _i P _PVi ^out + Σ _k P _Bk ^out ). Therefore, the individual output powers controlled by the power conditioners PCS _PVi and PCS _Bk are the active powers P _PVi ^out and P _Bk ^out , respectively. Therefore, the individual output power of each power conditioner PCS _PVi is _defined as P _PVi ^out, and the individual output power of each power conditioner PCS _Bk is _defined as P _Bk ^out .

The centralized management device MC2 centrally manages a plurality of power conditioners PCS _PVi and PCS _Bk . The centralized management device MC2 transmits and receives various information to and from each power conditioner PCS _PVi and PCS _Bk by, for example, wireless communication. Note that wired communication may be used instead of wireless communication.

In the photovoltaic power generation system PVS2 configured in this way, the centralized management device MC2 monitors a predetermined adjustment target power, and is an adjustment target based on the adjustment target power and the target power which is the target value of the adjustment target power. Calculate an index to match the power with the target power. Then, this is transmitted to each power conditioner PCS _PVi and PCS _Bk . Each power conditioner PCS _PVi (PCS _Bk ) receives an index from the centralized management device MC2, and based on the received index, the individual target power P, which is the target value of the individual output power P _PVi ^out (P _Bk ^out ). Calculate _PVi ^ref (P _Bk ^ref ). Then, the individual output power P _PVi ^out (P _Bk ^out ) is controlled based on the calculated individual target power P _PVi ^ref (P _Bk ^ref ). The index is information for setting the adjustment target power to the target power, and is information for calculating the individual target power P _PVi ^ref (P _Bk ^ref ).

Also in the photovoltaic power generation system PVS2, it is assumed that the electric power company instructs to suppress the output power. Therefore, in the photovoltaic power generation system PVS2 according to the present embodiment, the power conditioners PCS _PVi and PCS _Bk are distributedly controlled by using the above index, and the output power of the entire photovoltaic power generation system PVS2 is output command value P. Matches to ^C. That is, the photovoltaic power generation system PVS2 also performs output suppression control. Specifically, in photovoltaic systems PVS2, the central control device MC2 monitors the interconnection point power P (t), based on the linking point power P (t) and the output command value P ^C, continuous It calculates an index for matching system point power P (t) to the output command value P ^C. Then, this is transmitted to each power conditioner PCS _PVi and PCS _Bk . In the output suppression control according to the present embodiment, the index transmitted to each power conditioner PCS _PVi is defined as the suppression index pr _PV, and the index transmitted to each power conditioner PCS _Bk is defined as the charge / discharge index pr _B. Thus, inhibition index pr _PV is information for linking point power P (t) to the output command value P ^C, which is information for calculating the individual target power P _PVi ^ref. Further, charge and discharge indicator pr _B is information for linking point power P (t) to the output command value P ^C, which is information for calculating the individual target power P _Bk ^ref. Further, it is also information for determining how much the storage battery B _{k is} to be charged or discharged. Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref based on the suppression index pr _PV received from the centralized control device MC2. Then, the individual output power P _PVi ^out is controlled based on the calculated individual target power P _PVi ^ref . Each power conditioner PCS _Bk calculates an individual target power P _Bk ^ref based on the charge / discharge index pr _B received from the centralized control device MC2. Then, the individual output power P _Bk ^out is controlled based on the calculated individual target power P _Bk ^ref . Accordingly, it is made to coincide linking point power P (t) to the output command value P ^C.

FIG. 13 shows the functional configuration of the control system related to the output suppression control of the photovoltaic power generation system PVS2 shown in FIG. In FIG. 13, the solar cell SP _i and the storage battery B _k are not shown. As a control system related to the output suppression control, as shown in FIG. 13, each power conditioner PCS _PVi includes a receiving unit 11, a target power calculation unit 12', and an output control unit 13. Further, each power conditioner PCS _Bk includes a receiving unit 31, a target power calculation unit 32, and an output control unit 33. The centralized management device MC2 includes a target power setting unit 21, an interconnection point power detection unit 22, an index calculation unit 23', and a transmission unit 24'.

The target power calculation unit _{12'calculates} the individual target power P _PVi ^ref of the own device (power conditioner PCS _PVi ) based on the suppression index pr _PV received by the reception unit 11. Specifically, the target power calculation unit _{12'calculates} the individual target power P _PVi ^ref by solving the constrained optimization problem shown in the following equation (19). Therefore, the target power calculation unit _12'is different from the target power calculation unit 12 according to the first embodiment in the calculation formula of the optimization problem for calculating the individual target power P _PVi ^ref . In the equation (19), w _PVi represents the weight related to the active power suppression of the power conditioner PCS _PVi , and is a design value. Further, P _φi indicates a design parameter (hereinafter referred to as “priority parameter”) indicating whether or not to prioritize suppression of the individual output power P _PVi ^out of the power conditioner PCS _PVi , which is a design value. .. When the priority parameter P _φi is reduced, the charge amount of the storage battery B _k is reduced, and the individual output power P _PVi ^out is easily suppressed. On the other hand, when the priority parameter P _φi is increased, the charge amount of the storage battery B _k is increased, and it becomes difficult to suppress the individual output power P _PVi ^out . Therefore, it can be said that the priority parameter P _φi is a design parameter indicating whether or not to prioritize the charging of the storage battery B _k . In addition, this priority parameter P _.phi.i, the output limit according to the rated output of the power conditioner PCS _PVi separately, considered as pseudo output limits of the individual output power P _PVi ^out of the power conditioner PCS _PVi is set Be done. Therefore, the priority parameter _Pφi can be said to be a pseudo effective output limit. The weight w _PVi and the priority parameter _Pφi can be set by the user. Details of the following equation (19) will be described later.

The receiving unit 31 is configured in the same manner as the receiving unit 11 according to the first embodiment, and receives the charge / discharge index pr _B transmitted from the centralized management device MC2.

The target power calculation unit 32 calculates the individual target power P _Bk ^ref of the own device (power conditioner PCS _Bk ) based on the charge / discharge index pr _B received by the reception unit 31. Specifically, the target power calculation unit 32 calculates the individual target power P _Bk ^ref by solving the optimization problem shown in the following equation (20). In the equation (20), P _Bk ^lmt represents the rated output (output limit) of each power conditioner PCS _Bk . w _Bk represents the weight of the power conditioner PCS _Bk with respect to the active power. The weight w _Bk can be set by the user. Further, α _k and β _k represent adjustment parameters that can be adjusted according to the remaining amount of the storage battery B _k . The details of the following equation (20) will be described later.

The output control unit 33 is configured in the same manner as the output control unit 13 according to the first embodiment. The output control unit 33 controls the discharge and charge of the storage battery B _{k to set} the individual output power P _Bk ^out to the individual target power P _Bk ^ref calculated by the target power calculation unit 32. Specifically, when the individual target power P _Bk ^ref calculated by the target power calculation unit 32 is a positive value, the power (DC power) stored in the storage battery B _k is converted into AC power and used in the power system A. Supply. That is, the power conditioner PCS _{Bk is made} to function as a discharge circuit. On the other hand, when the individual target power P _Bk ^ref is a negative value, at least a part of the AC power output from the power conditioner PCS _PVi is converted into DC power and supplied to the storage battery B _k . That is, the power conditioner PCS _{Bk is made} to function as a charging circuit.

The index calculation unit 23'calculates an index for setting the interconnection point power P (t) as the target power. In the present embodiment, since the output command value P ^C is input as the target power, the index calculation unit 23'has a suppression index pr _PV for setting the interconnection point power P (t) to the output command value P ^C. The charge / discharge index pr _B is calculated. The index calculation unit 23'calculates the suppression index pr _PV and the charge / discharge index pr _B based on the following equations (21) and (22), where the Lagrange multiplier is λ, the gradient coefficient is ε, and the time is t. However, the index calculation unit 23 ', as the output command value P ^C from the target power setting unit 21, when it is entered the numerical value -1 to indicate that there is no command output suppression from power company, the Lagrange multiplier λ " 0 ”. That is, both the suppression index pr _PV and the charge / discharge index pr _B are calculated as “0”. In the following equation (21), since the individual output powers P _PVi ^out , P _Bk ^out and the output command value P ^C are values that change with respect to time t, the individual output powers are respectively P _PVi ^out (t). describes a P _Bk ^out (t) and the output command value and P ^C (t). Details of the following equations (21) and (22) will be described later.

The transmission unit 24'transmits the suppression index pr _PV calculated by the index calculation unit _{23'to the} power conditioner PCS _PVi, and transmits the charge / discharge index pr _B calculated by the index calculation unit 23'to the power conditioner PCS _Bk . ..

Next, in the output suppression control performed by the photovoltaic power generation system PVS2, the reason why the above equation (19) is used to calculate the individual target power P _PVi ^ref by the power conditioner PCS _PVi , and the individual target power P by the power conditioner PCS _{Bk. The} reason why the above formula (20) is used for the calculation of _Bk ^ref , and the reason why the above formula (21) and the above formula (22) are used for the calculation of the suppression index pr _PV and the charge / discharge index pr _B by the centralized control device MC2. Will be explained.

The photovoltaic power generation system PVS2 is configured to achieve the following five goals in output suppression control. The first goal (Goal 2-1) is that "each power conditioner PCS _PVi and PCS _Bk calculate individual target power in a distributed manner". The second goal (Goal 2-2) is to "do not suppress the output power of the power conditioner PCS _PVi connected to the solar cell as much as possible". The third target (target 2-3) is that "the storage battery is charged when the interconnection point power is larger than the output command value (target power), and discharged when it is insufficient". is there. The fourth target (target 2-4) is to "match the output power (interconnection point power) at the interconnection point of the photovoltaic power generation system PVS2 with the output command value (target power) from the electric power company". is there. The fifth goal (2-5) is to "enable the output suppression amount to be adjusted for each power conditioner PCS _PVi and PCS _Bk ".

First, consider a constrained optimization problem when the centralized management device MC2 centrally obtains individual target powers P _PVi ^ref and P _Bk ^ref . Then, the following equation (23) is obtained. Here, as described above, P _PVi ^ref and P _Bk ^ref represent the individual target powers of the respective power conditioners PCS _PVi and PCS _Bk , respectively, and P _PVi ^lmt and P _Bk ^lmt represent the individual target powers of the respective power conditioners PCS _PVi , respectively. , PCS _Bk 's rated output (output limit), P _φi represents the priority parameter. The individual target powers P _PVi ^ref and P _Bk ^ref, which are the optimum solutions of the following equation (23), are set to (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^* , respectively. In the following equation (23), the equation (23a) is the minimization of the output suppression amount of the individual output power P _PVi ^out of each power conditioner PCS _PVi and the output amount of the individual output power P _Bk ^out of each power conditioner PCS _Bk. Equation (23b) is the constraint by the rated output P _PVi ^lmt of each power conditioner PCS _PVi , and equation (23c) is the constraint by the rated output P _Bk ^lmt of each power conditioner PCS _Bk , equation (23d). the remaining constraints of the storage batteries B _k, (23e) expression to match interconnection point power P (t) to the output command value P ^C, represents respectively.

This shows the case where the centralized control device MC2 obtains the individual target powers (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^* from the above equation (23). Therefore, in the case of the above equation (23), since the power conditioners PCS _PVi and PCS _Bk do not calculate the individual target powers (P _PVi ^ref ) ^* and (P _Bk ^ref ) ^* in a distributed manner, the target 2-1 Has not been achieved.

Next, consider a constrained optimization problem when each power conditioner PCS _PVi obtains an individual target power P _PVi ^ref in a distributed manner. Then, the following equation (24) is obtained.

Similarly, consider a constrained optimization problem when each power conditioner PCS _Bk finds the individual target power P _Bk ^ref in a distributed manner. Then, the following equation (25) is obtained.

However, the individual target power which is the optimum solution of the above equation (24) is the individual target power P _PVi ^ref distributed by each power conditioner PCS _PVi , but the above equation (23e) is not taken into consideration. Similarly, the individual target power which is the optimum solution of the above equation (25) is the individual target power P _Bk ^ref distributed by each power conditioner PCS _Bk , but the above equation (23e) is not taken into consideration. .. Thus, unable to achieve the target 2-4 to match the interconnection point power P (t) to the output command value P ^C from the power company.

Therefore, next, let us consider achieving the goal 2-4 by the method. That is, each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref in a distributed manner based on the suppression index pr _PV received from the centralized management device MC2, and each power conditioner PCS _Bk is the centralized management device MC2. The individual target power P _Bk ^ref is calculated in a distributed manner based on the charge / discharge index pr _B received from. As a result, Goal 2-4 is achieved. The constrained optimization problem when each power conditioner PCS _PVi obtains the individual target power P _PVi ^ref in a distributed manner using the suppression index pr _PV can be expressed by the above equation (19). The individual target power P _PVi ^ref , which is the optimum solution of the above equation (19), is set to (P _PVi ^ref ) ^♭ . Similarly, the constrained optimization problem when each power conditioner PCS _Bk obtains the individual target power P _Bk ^ref in a distributed manner using the charge / discharge index pr _B can be expressed by the above equation (20). .. The individual target power P _Bk ^ref , which is the optimum solution of the above equation (20), is set to (P _Bk ^ref ) ^♭ .

Here, the optimum solution (P _PVi ^ref ) ^* obtained by the above equation (23) and the optimum solution (P _PVi ^ref ) ^♭ obtained by the above equation (19) match, and the above equation (23) is used. When the obtained optimum solution (P _Bk ^ref ) ^* and the optimum solution (P _Bk ^ref ) ^♭ obtained by the above equation (20) match, the interconnection point power P (t) is output from the electric power company. it can be matched to the value P ^C. That is, even when the power conditioners PCS _PVi and PCS _Bk solve the optimization problem in a distributed manner, the goals 2-4 can be achieved. Therefore, focusing on the optimality of the steady state, the suppression index pr _PV , which is (P _PVi ^ref ) ^* = (P _PVi ^ref ) ^♭ , and the charge / discharge, which is (P _Bk ^ref ) ^* = (P _Bk ^ref ) ^♭. Consider the index pr _B. Therefore, the KKT conditions of the above equation (23), the above equation (19), and the above equation (20) are considered. As a result, the following equation (26) is obtained from the KKT condition of the above equation (23), the following equation (27) is obtained from the KKT condition of the above equation (19), and the following equation (20) is obtained from the KKT condition of the above equation (20). 28) Equation is obtained. Note that μ and ν are predetermined Lagrange multipliers.

From the above equations (26), (27), and (28), by setting pr _PV = pr _B = λ (the above equation (22)), (P _PVi ^ref ) ^* and (P) It can be seen that _PVi ^ref ) ^♭ and (P _Bk ^ref ) ^* and (P _Bk ^ref ) ^♭ match. Therefore, the centralized management device MC2 calculates the Lagrange multiplier λ and presents (transmits) the calculated Lagrange multiplier λ as the suppression index pr _PV to each power conditioner PCS _PVi , so that each power conditioner PCS _PVi has its own The individual target power (P _PVi ^ref ) ^♭ can be calculated from the above equation (19). Similarly, the centralized management device MC2 presents (transmits) the calculated Lagrange multiplier λ as the charge / discharge index pr _B to each power conditioner PCS _Bk , so that each power conditioner PCS _Bk has the above (20). The individual target power (P _Bk ^ref ) ^♭ can be calculated from the formula. As a result, even when each power conditioner PCS _PVi and PCS _Bk obtain the individual target power P _PVi ^ref and P _Bk ^ref in a distributed manner, the interconnection point power P (t) and the output command from the power company The value P ^C can be matched. That is, the goal 2-4 can be achieved.

Next, a method of calculating the Lagrange multiplier λ by the centralized management device MC2 will be described. In order to obtain the Lagrange multiplier λ, first, h ¹ _{1, i} = −P _PVi ^ref , h ¹ _{2, i} = P _PVi ^ref −P _PVi ^lmt, and the inequality constraints of each power conditioner PCS _PVi are collectively h ¹ _{Let x, i} ≤ 0 (x = 1, 2, i = 1, ..., N). Similarly, h ² _{1, k} = −P _Bk ^lmt −P _Bk ^ref , h ² _{2, k} = P _Bk ^ref −P _Bk ^lmt , h ² _{3, k} = α _k −P _Bk ^ref , h ² _{4 , k} = P _Bk ^ref −β _k, and the inequality constraints of each power conditioner PCS _Bk are collectively h ² _{y, k} ≦ 0 (y = 1,2,3,4, k = 1, ···, m ). Then, consider the following equation (29), which is the dual problem of equation (23).

Here, assuming that the optimum solution (P _PVi ^ref ) ^♭ , (P _Bk ^ref ) ^♭ obtained by each power conditioner PCS _PVi and PCS _Bk is determined, the following equation (30) is obtained, and the maximum for the Lagrange multiplier λ is obtained. It becomes a form of the conversion problem. When the gradient method is applied to the following equation (30), the following equation (31) is obtained. Note that ε represents the gradient coefficient and τ represents the time variable.

In the above equation (31), (P _PVi ^ref ) ^♭ is replaced with the individual output power P _PVi ^out of the corresponding power conditioner PCS _PVi , and (P _Bk ^ref ) ^♭ is replaced with the individual output power P of the corresponding power conditioner PCS _{Bk. Replace} with _Bk ^out . Further, the centralized management device MC2 does not individually observe the individual output powers P _PVi ^out and P _Bk ^out of each power conditioner PCS _PVi and PCS _Bk , and the interconnection point power P (t) = Σ _i P _PVi ^out + Σ. Observe _k P _Bk ^out . Further, it is assumed that the sequential output command value P ^C is acquired from the electric power company. Then, the above equation (21) is obtained. Thus, the central control device MC2, based on the interconnection point power P (t) and the output command value P ^C from the power company may calculate the Lagrange multiplier lambda. Then, the Lagrange multiplier λ calculated based on the above equation (22) is set as the suppression index pr _PV and the charge / discharge index pr _B.

From the above, in the present embodiment, each power conditioner PCS _PVi uses the optimization problem shown in the above equation (19) when calculating the individual target power P _PVi ^ref . Further, each power conditioner PCS _Bk uses the optimization problem shown in the above equation (20) when calculating the individual target power P _Bk ^ref . Then, the centralized management device MC2 uses the above equations (21) and (22) when calculating the suppression index pr _PV and the charge / discharge index pr _B.

Next, in the photovoltaic power generation system PVS2 configured as described above, it was verified by simulation that the above five goals were achieved and the system was operating properly.

In the simulation, 5 power conditioner PCS _PVi to which the solar cell SP _i is connected (i = 1 to 5; PCS _{PV1 to} PCS PV5) and ₅ power conditioner PCS _Bk to which the storage battery B _k is connected (i = 1 to 5; PCS _{PV1 to} PCS PV5). A photovoltaic power generation system PVS2 having k = 1 to 5; PCS _{B1 to} PCS _B5 ) was assumed.

Further, in this simulation, the model of the storage battery B _{k is, d / dt (x k)} = - K k P Bk out, was s _k = x _k. Here, s _k denotes the charged electrical energy of the storage battery B _k, K _K represents the characteristic of the battery B _k. Further, the adjustment parameters α _k and β _k that can be adjusted according to the remaining amount of the storage battery B _k are set as shown in Table 1. In Table 1, SOC _k indicates the charge rate (State Of Charge) [%] of each storage battery B _Bk , the charge power amount [kWh] is _Sk , and the maximum capacity [kWh] of the storage battery B _k is S. _{As k} ^max , it is calculated by SOC _k = (S _k / S _k ^max ) × 100.

The priority parameter (pseudo effective output limit) P _φi of each power conditioner PCS _PVi , which is a parameter related to the optimization problem, was set to 1000 [kW]. In addition, the model of the power system A (interconnection point voltage) (see the above equation (18)) and the models of the power conditioners PCS _PVi and PCS _Bk (see FIGS. 3 and 4) _{relate to} the first embodiment. It was the same as the one at the time of simulation.

14 to 16 show the results when the simulation was performed under a plurality of conditions using the photovoltaic power generation system PVS2 of the model shown above.

Case 1, all five of the power conditioner PCS _PV1 ~PCS _PV5 the same conditions, a case where all five of the power conditioner PCS _B1 ~PCS _B5 are the same conditions was simulated. Let the simulation be simulation 2-1. In the simulation 2-1, all five of the power conditioner PCS _PV1 ~PCS _PV5 is rated output P _PVi ^lmt is 500 [kW], the weights w _PVi about active power suppression 1.0, the amount of power generated by solar cell SP _i P _i ^SP has to be 600 [kW]. In addition, all five power conditioners PCS _{B1 to} PCS _B5 have a rated output P _PVi ^lmt of 500 [kW] and a weight w _PVi related to active power suppression of 1.0. The maximum capacities S ₁ ^{max to} S ₅ ^max of the storage batteries B _{1 to} B ₅ are all assumed to be 500 [kWh]. Then, the output command value P ^C from the electric power company is assumed to be 1500 [kW] when there is no command when 0 ≦ t <60 [s] and when 60 ≦ t [s]. When "there is no command of the output command value P ^C ", the numerical value -1 indicating that there is no command is used as the output command value P ^C as described above. In addition, the gradient coefficient ε is 0.05, the suppression index pr _PV and charge / discharge index pr _B performed by the centralized control device MC2 are updated, and the individual target powers P _PVi ^ref and P _Bk ^ref performed by each power conditioner PCS _PVi and PCS _Bk. Each sampling time with the update of was set to 1 [s]. Further, it was assumed that all the power conditioners PCS _PVi and PCS _Bk were operated at a power factor of 1 (reactive power target value = 0 [kvar]). FIG. 14 shows the simulation results in simulation 2-1.

FIG. 14 (a) shows a power generation amount P _i ^SP solar cell SP _i. FIG. 14B shows the individual target power P _PVi ^ref of each power conditioner PCS _PVi . FIG. 14C shows the individual output power P _PVi ^out of each power conditioner PCS _PVi . FIG. 14 (d) shows the linking point power P (t) output command value from the (solid line) and electric power company P ^C (dashed line). FIG. _14E shows the individual target power P _Bk ^ref of each power conditioner PCS _Bk . FIG. 14 (f) shows the individual output power P _Bk ^out of each power conditioner PCS _Bk . FIG. 14 (g) shows the suppression index pr _PV and the charge / discharge index pr _B calculated by the index calculation unit 23'.

The following can be confirmed from FIG. That is, as shown in FIG. 14 (b) and FIG. 14 (c), the even after the command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _PV1 ^ref ~P _PV5 ^ref It remains at 500 [kW], and it can be confirmed that the individual output powers P _PV1 ^{out to} P _PV5 ^out are not suppressed. Further, as shown in FIGS. 14 (e) and 14 (f), the individual output powers P _B1 ^{out to} P _B5 ^{out of} each power conditioner PCS _Bk transition from 0 [kW] to negative (minus). It can be confirmed that there is. This indicates that electric power is input to the power conditioner PCS _Bk, and the electric power input to each power conditioner PCS _Bk is used to charge the storage battery B _k . Further, as shown in FIG. 14 (d), the interconnection point power P (t) can also be confirmed that it matches the output command value P ^C. Thus, solar systems PVS2, when the output command value P ^C from the power company is commanded not suppress individual output power P _PVi ^out of the power conditioner PCS _PVi, is used to charge the battery B _k Can be confirmed.

Case 2, the five power conditioner PCS _B1 ~PCS maximum capacity of the storage battery B _5, which is connected to one of the power conditioner PCS _B5 of _B5 S ₅ ^max other power conditioner PCS _B1 ~PCS _B4 A case different from that of the connected storage batteries B _{1 to} B ₄ was simulated. Let the simulation be simulation 2-2. In the simulation 2-2 was the maximum capacity S ₅ ^max storage battery B ₅ connected to a single power conditioner PCS _B5 and 3 [kWh]. Other conditions were the same as in Simulation 2-1. FIG. 15 shows the simulation results in simulation 2-2. In FIG. 15, FIGS. 15 (a) to 15 (g) are diagrams corresponding to FIGS. 14 (a) to 14 (g) in the simulation 2-1.

The following can be confirmed from FIG. That is, as shown in FIG. 15 (a) ~ (c) , similarly to the simulation 2-1, even after a command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _It can be confirmed that _PV1 ^{ref to} P _PV5 ^ref are not suppressed. Further, as shown in FIGS. 15 (e) and 15 (f), the individual output powers P _B1 ^{out to} P _B5 ^out of the power conditioners PCS _{B1 to} PCS _B5 change from 0 [kW] to negative (minus). It can be confirmed that the transition has occurred. Therefore, as in the simulation 2-1 above, each of the power conditioners PCS _{B1 to} PCS _B5 uses the input electric power to charge the storage battery B _k . Further, as shown in FIGS. 15 (e) and 15 (f), when 110 ≦ t [s], the individual output power P _B5 ^out of the power conditioner PCS _B5 becomes 0 (zero), and other power conditioners. PCS _B1 individual output power P _B1 ^out ~P _B4 ^out of ～PCS _B4 is further decreased (the input power is increasing). This is because the maximum capacity S ₅ ^max of the storage battery B ₅ is 3 [kWh], which is lower than the other storage batteries B _{1 to} B ₄ , so that t = 110 [s], and the storage battery B ₅ is the other storage battery B ₁ to B ₁ to. before the B ₄ represents that the charging is completed. Thus, since the charging of the battery B ₅ is completed, it stops the input power to the power conditioner PCS _B5, represents that it stops charging. Then, the power due to distribute conditioner PCS _B5 minute power which has been input to the other of the power conditioner PCS _B1 ~PCS _B4, other power conditioner PCS _B1 ~PCS _B4 individual output power P _B1 ^out to P _B4 ^out is further reduced (power input is increasing). Furthermore, as shown in FIG. 15 (d), the with the charge stop the battery B _5, and temporarily linking point power P (t) becomes greater than the output command value P ^C. However, in the steady state, interconnection point power P (t) can also be confirmed that it matches the output command value P ^C. Therefore, it can be said that the photovoltaic power generation system PVS2 operates appropriately in consideration of the performance of each storage battery B _k .

Case 3, the weight w _B5 is set to the other of the power conditioner PCS _B1 ~PCS _B4 relates active power is set to one of the power conditioner PCS _B5 of five power conditioner PCS _B1 ~PCS _B5 A different case was simulated. Let the simulation be simulation 2-3. In simulation 2-3, the weight w _B5 regarding the active power of the one power conditioner PCS _B5 was set to 2.0. That is, it means that the charge amount is halved as compared with that of other power conditioners PCS _{B1 to} PCS _B4 . Other conditions were the same as in Simulation 2-1. FIG. 16 shows the simulation results in Simulation 2-3. In FIG. 16, FIGS. 16 (a) to 16 (g) are diagrams corresponding to FIGS. 14 (a) to 14 (g) in the simulation 2-1.

The following can be confirmed from FIG. That is, as shown in FIG. 16 (a) ~ (c) , similarly to the simulation 2-1, even after a command output command value ^{P C (60 ≦ t [s} ]), the individual target power P _It can be confirmed that _PV1 ^{ref to} P _PV5 ^ref are not suppressed. Further, from FIG. 15 (e) and FIG. 15 (f), the individual output power P _B1 ^out ~P _B5 ^out of the power conditioner PCS _B1 ~PCS _B5 has a transition from 0 [kW] negative (minus) Can be confirmed. Therefore, as in the simulation 2-1 above, each of the power conditioners PCS _{B1 to} PCS _B5 uses the input electric power to charge the storage battery B _k . Further, as shown in FIGS. 16 (e) and 16 (f), the charge amount (input power to the power conditioner PCS _B5 ) of the power conditioner PCS _B5 having different weights w _B5 regarding the active power is the other power. It can be confirmed that the conditioners are half of PCS _{B1 to} PCS _B4 . Then, as shown in FIG. 16 (d), the interconnection point power P (t) can also be confirmed that it matches the output command value P ^C in the steady state. Therefore, it can be said that the photovoltaic power generation system PVS2 is operating appropriately in consideration of the weight w _Bk regarding the active power set in the power conditioner PCS _Bk .

The following can be confirmed by comparing FIGS. 14 to 16 in addition to the results for each of FIGS. 14 to 16. That is, as shown in each figure (g), suppression indicators pr _PV and charge-discharge index pr _B is, in each power conditioner _{PCS PV1 ~PCS PV5, PCS B1 ~PCS} B5, power generation amount P of the solar cell SP _i Different values are calculated based on _i ^SP , performance of storage battery B _k , rated output P _PVi ^lmt , P _Bk ^lmt , weight w _PVi related to active power suppression, weight w _Bk related to active power, and output command value P ^C. It can be confirmed that Then, as shown in (b) and (e) of each figure, the individual target powers P _PVi ^ref and P _Bk ^ref are updated according to the update of the suppression index pr _PV and the charge / discharge index pr _B. You can check. Each power conditioner _{PCS PV1 ~PCS PV5, PCS B1 ~PCS} B5 , the individual target power P _PVi ^ref, depending on the P _Bk ^ref, and controls the individual output power P _PVi ^out, P _Bk ^out. Therefore, as shown in each figure (d), it can be confirmed that the interconnection point power P (t) coincides with the output command value P ^C. From the above, it can be said that the suppression index pr _PV and the charge / discharge index pr _B calculated by the centralized control device MC2 using the above equations (21) and (22) are appropriate values.

From the results of the above simulations 2-1 to 2-3, in the photovoltaic power generation system PVS2, each power conditioner PCS _PVi is distributed and individually targeted power based on the suppression index pr _PV received from the centralized management device MC2. The P _PVi ^ref is calculated. Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref in a distributed manner based on the charge / discharge index pr _B received from the centralized management device MC2. Therefore, the above target 2-1 has been achieved. Each power conditioner PCS _PVi are individually output power P _PVi ^out not suppress as much as possible, the amount of interconnection point power P (t) exceeds the output command value P ^C, the power conditioner PCS enter to _Bk, it is available to charge the battery B _k. Therefore, the above-mentioned Goal 2-2 and the above-mentioned Goal 2-3 have been achieved. Furthermore, interconnection point power P (t) coincides with the output command value P ^C. Therefore, the above goals 2-4 have been achieved. Then, the individual output powers P _PVi ^out and P _Bk ^out are changed for each power conditioner PCS _PVi and PCS _Bk according to various conditions. That is, the output suppression amount changes for each of the power conditioners PCS _PVi and PCS _Bk according to various conditions. Therefore, the above target 2-5 has been achieved. From the above, it can be seen that the photovoltaic power generation system PVS2 has achieved the above five goals.

As described above, in the photovoltaic power generation system PVS2 according to the second embodiment, the central control device MC2 is suppressed index pr from the output command value P ^C and detected interconnection point power P from the power company (t) Calculate _PV and charge / discharge index pr _B. Then, the suppression index pr _PV is transmitted to each power conditioner PCS _PVi , and the charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk . Further, each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref by solving the optimization problem of the above equation (19) in a distributed manner based on the received suppression index pr _PV . Then, the individual output power P _PVi ^out is controlled by the individual target power P _PVi ^ref . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref by solving the optimization problem of the above equation (20) in a distributed manner based on the received charge / discharge index pr _B. Then, the individual output power P _Bk ^out is controlled to the individual target power P _Bk ^ref . As a result, the centralized management device MC2 has only the simple calculations shown in the above equations (21) and (22). Therefore, in the photovoltaic power generation system PVS2, the processing load of the centralized management device MC2 can be reduced. In addition, each power conditioner PCS _PVi and PCS _Bk calculate the individual target power P _PVi ^ref and P _Bk ^ref in a distributed manner based on the suppression index pr _PV and the charge / discharge index pr _B , respectively, and the individual output power P _PVi ^out , Even when controlling P _Bk ^out , the interconnection point power P (t) can be matched with the output command value P ^C from the power company.

In the first embodiment, the weight w _i related to the active power suppression is taken into consideration, and in the second embodiment, the weight w _PVi related to the active power suppression and the weight w _Bk related to the active power are taken into consideration. However, it is not limited to this. For example, in the first embodiment, if it is not necessary to consider the target 1-3 "enable the output suppression amount to be adjusted for each power conditioner PCS _i ", it is set for each power conditioner PCS _i. The weights w _i related to the above active power suppression may all have the same value (for example, “1”). Similarly, in the second embodiment, unless it is necessary to consider the target 2-5 "to enable the output suppression amount to be adjusted for each power conditioner PCS _PVi and PCS _Bk ", the power conditioner PCS _The weight w related to the active power suppression set for each _PVi and PCS _Bk may be the same value (for example, “1”) for the _PVi and the weight w _Bk related to the active power.

In the second embodiment, the case where the target power calculation unit _{12'calculates} the individual target power P _PVi ^ref by using the priority parameter P _φi as in the above equation (19) has been described as an example. The rated output P _PVi ^lmt may be used as in the above equation (8) in the first embodiment. In this case, whether to prioritize the suppression of the individual output power P _PVi ^out or the charge / discharge of the storage battery B _k (individual output power P _Bk ^out ) is the weight related to the active power suppression w The weight related to _PVi and the active power. It can be adjusted with w _Bk .

In the second embodiment, the optimization problem solved by the target power calculation unit 12'is not limited to the above equation (19). For example, the following equation (19') may be used instead of the above equation (19). The following equation (19') has an additional output current constraint of each power conditioner PCS _PVi shown in the following equation (19c') as compared with the above equation (19). In the following equation (19'), Q _PVi is the ineffective power of each power conditioner PCS _PVi , S _PVi ^d is the maximum apparent power that can be output by each power conditioner PCS _PVi , and V ₀ is the interconnection at the time of design. The reference voltage of the point, V _PVi , indicates the voltage of the interconnection point in each power conditioner PCS _PVi . Further, in the following equation (19'), instead of the output current constraint of each power conditioner PCS _PVi shown in the following equation (19c'), the rated capacity constraint of the power conditioner PCS _PVi shown in the following equation (19d') is applied. You may use it.

In the second embodiment, the optimization problem solved by the target power calculation unit 32 is not limited to the above equation (20). For example, the following equation (20') may be used instead of the above equation (20). In the following equation (20'), a weight w _SOCk corresponding to the SOC of the storage battery B _k is added in the evaluation function shown in the following (20a') as compared with the above equation (20). This weight w _SOCk is calculated by the following equation (32). The In (32), A _SOC's w _SOCK offset, K _SOC is the weight w _SOCK gain, s is the weight w _SOCK ON / OFF switch (e.g., 1 When on, the off-0), SOC _k Indicates the SOC of the current storage battery B _k , and SOC _d indicates the reference SOC. Further, the C rate constraint of the storage battery B _k shown in the following equation (20c') and the output current constraint of each power conditioner PCS _Bk shown in the following equation (20e') are added to the constraints. The C rate is a relative ratio of the charging time or the time of the discharge current to the total capacitance of the storage battery B _k, obtained by the 1C when to charge or discharge the total capacitance of the storage battery B _k at 1 hour is there. In the present embodiment, the C rate on the charging side is set to the charging rate C _rate ^M , the C rate on the discharging side is set to the discharging rate C _rate ^P, and predetermined values (for example, both 0.3C) are set in advance. .. In the following equation (20'), P _SMk ^lmt is the rated output of the storage battery B _k obtained by −C _rate ^M × WH _S ^lmt (WH _S ^lmt is the rated output capacity of the storage battery B _k ), and P _SPk ^lmt is C _rate ^P × WH _S discharge rated output of the storage battery B _k sought ^lmt, Q _Bk reactive power of the power conditioner PCS _Bk, S _Bk ^d is printable maximum apparent power of the power conditioner PCS _Bk, V _Bk indicates the voltage at the interconnection point in each power conditioner PCS _Bk . Further, in the charge rated output _PSMk ^lmt of the storage battery B _k , the storage battery charge amount correction according to the SOC shown in the following equation (33) is taken into consideration, with the correction start SOC as SOC _C and the SOC charge limit threshold value as cMAX. .. The storage battery charge amount correction is performed as usual until the correction start SOC, and the output is linearly corrected so that the output becomes 0 at the SOC upper limit from the correction start SOC to the SOC upper limit. There is. Further, in the following equation (20'), instead of the output current constraint of each power conditioner PCS _Bk shown in the following (20e'), the rated capacity constraint of each power conditioner PCS _Bk shown in the following equation (20f') is set. You may use it.

In the photovoltaic power generation system according to another embodiment described below, when the target power calculation unit _{12'calculates} the individual target power P _PVi ^ref , the above formula (19) or the above formula (19') Any of these optimization problems may be used. Similarly, the target power calculation unit 32 may use either the optimization problem of the above equation (20) or the above equation (20') when calculating the individual target power P _Bk ^ref .

Next, the photovoltaic power generation system PVS3 according to the third embodiment will be described. In the following description, the same or similar components as those in the first embodiment and the second embodiment are designated by the same reference numerals and the description thereof will be omitted. FIG. 17 shows the overall configuration of the photovoltaic power generation system PVS3. As shown in the figure, the photovoltaic power generation system PVS3 includes a plurality of solar cells SP _i , a plurality of power conditioner PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioner PCS _Bk , and a centralized management device. It is configured to have MC3 and a power load L. Therefore, it differs from the photovoltaic power generation system PVS2 according to the second embodiment in that it further includes a power load L.

The electric power load L consumes the supplied electric power, and is, for example, a factory or a general household. The power load L is connected to the interconnection point, and power is supplied from the power system A, each power conditioner PCS _PVi , and each power conditioner PCS _Bk .

In such a photovoltaic power generation system PVS3, the power generated by the solar cell SP _i and output from each power conditioner PCS _PVi (total of each individual output power P _PVi ^out ΣP _PVi ^out ) is the charge of the storage battery B _k . And the power load L, but the surplus power that is not consumed by these flows back to the power system A. Even when the thus excess power is reverse flow, is instructed to output suppressing electric power company, it is necessary to not exceed the output command value P ^C from the power company. Since this surplus power can be regarded as the interconnection point power P (t) detected by the interconnection point power detection unit 22, the photovoltaic power generation system PVS3 has the suppression index pr _PV and charge / discharge as in the second embodiment. Output suppression control is performed using the index pr _B. That is, the target power (output command value P ^C) an interconnection point power P (t). Thus, so that the surplus power does not exceed the output command value P ^C.

FIG. 18 shows the functional configuration of the control system related to the output suppression control of the photovoltaic power generation system PVS3 shown in FIG. In FIG. 18, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. As shown in the figure, the configurations of the power conditioners PCS _PVi and PCS _{Bk according} to the third embodiment and the centralized management device MC3 are the power conditioners PCS _PVi and PCS _{Bk according} to the second embodiment. The configuration is the same as that of the centralized management device MC2 (see FIG. 13).

According to the solar power generation system PVS3 according to the present embodiment, the central control device MC3, based on the output command value P ^C and linking point power P from the power company (t), suppression indicators pr _PV and charge-discharge index The pr _B is calculated. At this time, the centralized management device MC3 calculates the suppression index pr _PV and the charge / discharge index pr _B by using the above equations (21) and (22). Then, each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref in a distributed manner based on the suppression index pr _PV . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref in a distributed manner based on the charge / discharge index pr _B. As a result, the processing load of the centralized management device MC3 can be reduced. Furthermore, interconnection point power P (t), i.e., it is possible to control the surplus power to be backward flow to the power grid A to the output command value P ^C. Therefore, the surplus electric power to be reverse-flowed to the electric power system A can be prevented from exceeding the output command value P ^C from the electric power company.

In the third embodiment, the case where the power load L is added to the photovoltaic power generation system PVS2 according to the second embodiment has been described as an example, but the power is supplied to the photovoltaic power generation system PVS1 according to the first embodiment. Even when the load L is added, the output suppression control can be performed by using the suppression index pr. Again, while the linking point power P (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device MC1.

Next, the photovoltaic power generation system PVS4 according to the fourth embodiment will be described. The overall configuration of the photovoltaic power generation system PVS4 is substantially the same as that of the photovoltaic power generation system PVS3 (see FIG. 17) according to the third embodiment.

In the above-described third embodiment has been described the case where the individual output power P _PVi ^out of the power conditioner PCS _PVi (power generation amount P _i ^SP solar cell SP _i) exceeds than the power consumption of the power load L. In the fourth embodiment, on the contrary, the total ΣP _PVi ^out of the individual output powers P _PVi ^out (power generation amount P _i ^SP of the solar cell SP _i ) of each power conditioner PCS _PVi is less than the power consumption of the power load L. It is assumed that there is. That is, a part or all of the insufficient power that is insufficient in the power generation amount P _i ^SP of the solar cell SP _i is supplied from the power system A. The power shortage is the difference between the individual output power P _PVi ^out of total .SIGMA.P _PVi ^out and the power consumption.

In such a photovoltaic power generation system PVS4, in order to supply the insufficient power from the power system A, it is necessary to buy (purchase) power from the power company. Then, the electricity bill is paid to the electric power company for the amount of electricity purchased. Electricity charges include basic charges and pay-as-you-go charges. The basic charge is determined by the maximum value (peak value) of, for example, the amount of electricity used every 30 minutes recorded by the electricity meter provided at the interconnection point. Specifically, the contracted power is determined based on the peak value of the power consumption, and when the contracted power is high, the basic charge is high, and when the contracted power is low, the basic charge is low.

Therefore, in the photovoltaic power generation system PVS4 according to the fourth embodiment, the power conditioners PCS _PVi and PCS _Bk are distributedly controlled by using the suppression index pr _PV and the charge / discharge index pr _B , and the power system A Suppress the peak value of the supplied power (purchased power). This is called "peak cut control". The purchased power is the magnitude of the power supplied from the power system A to the photovoltaic power generation system PVS4, that is, the power obtained (purchased) from the photovoltaic power system A by the photovoltaic power generation system PVS4. As described above, the interconnection point power P (t) has a positive value when it is output from the photovoltaic power generation system PVS4 to the power system A (in the case of reverse power flow). Therefore, when the power system A inputs the power to the photovoltaic power generation system PVS4, the interconnection point power P (t) becomes a negative value. In the case of peak cut control for controlling the power purchase power, the target value is set as a negative value, and the interconnection point power P (t) is controlled so as not to fall below the target value. In the peak cut control, the photovoltaic power generation system PVS4 controls the individual output power P _PVi ^out of each power conditioner PCS _PVi , and outputs all the power generated by the solar cell SP _i . In addition, the individual output power P _Bk ^out of each power conditioner PCS _Bk is controlled, and the power stored in the storage battery B _k is discharged as needed. In this way, by supplementing a part of the power consumption of the power load L with the power generated by the solar cell SP _i and the power stored in the storage battery B _k , the increase in the purchased power is suppressed. ..

FIG. 19 shows the functional configuration of the control system related to the peak cut control of the photovoltaic power generation system PVS4. In FIG. 19, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. As a control system for the peak cut control, the photovoltaic power generation system PVS4 includes a centralized management device MC4 instead of the centralized management device MC3 as compared with the photovoltaic power generation system PVS3 according to the third embodiment. Is different.

In the centralized management device MC4, the target power setting unit 21 sets the peak cut target value P _cut with the upper limit as a negative value as the target power based on the upper limit of the purchased power. This peak cut target value P _cut is a target value of the interconnection point power P (t) and is a negative value. The peak cut target value P _cut can be freely specified by the user. The target power setting unit 21 outputs the set target power (peak cut target value P _cut ) to the index calculation unit 23'. Therefore, in the present embodiment, the peak cut target value P _cut is used as the target power instead of the output command value P ^C.

Further, in the centralized management device MC4, the index calculation unit 23'uses the interconnection point power P (t) and the peak cut target value P _cut input from the target power setting unit 21, and uses the suppression index pr _PV and the suppression index pr _PV. The charge / discharge index pr _B is calculated. That is, in the present embodiment, the index calculation unit 23'calculates the suppression index pr _PV and the charge / discharge index pr _{B for} setting the interconnection point power P (t) to the peak cut target value P _cut . At this time, the index calculation unit _{23'calculates} the Lagrange multiplier λ by using the peak cut target value P _cut instead of the output command value P ^C (t) in the above equation (21). Then, the Lagrange multiplier λ calculated by the above equation (22) is calculated as the charge / discharge index pr _B. Note that the suppression indicators pr _PV, electric power generated by the solar cell SP _i from the power conditioner PCS _PVi is so is output every fixed value "0" is used. Therefore, it can be said that the index calculation unit 23'calculates only the charge / discharge index pr _B. The index calculation unit 23'transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 24'. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 24'.

In the photovoltaic power generation system PVS4 configured in this way, the centralized management device MC4 monitors the interconnection point power P (t) detected by the interconnection point power detection unit 22. Then, when the interconnection point power P (t) becomes equal to or less than the peak cut target value P _cut , the index calculation unit 23'suppresses the interconnection point power P (t) to be the peak cut target value P _cut. The index pr _PV (= 0) and the charge / discharge index pr _B are calculated. Each power conditioner PCS _PVi calculates an individual target power P _PVi ^ref based on an optimization problem using the suppression index pr _PV calculated by the centralized control device MC4, and the individual output power P _PVi ^out is the individual target power. It is controlled to be P _PVi ^ref . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref based on the optimization problem using the charge / discharge index pr _B calculated by the centralized management device MC4, and sets the individual output power P _Bk ^out . Control to individual target power P _Bk ^ref . As a result, when the interconnection point power P (t) is equal to or less than the peak cut target value P _cut , all the power generated by the solar cell SP _i is output, and the power stored in the storage battery B _k is discharged. Will be done. As a result, the interconnection point power P (t) rises, and the interconnection point power P (t) becomes the peak cut target value P _cut . Therefore, the photovoltaic power generation system PVS4 suppresses the peak value by suppressing the interconnection point power P (t) from becoming equal to or less than the peak cut target value P _cut .

When the interconnection point power P (t) is equal to or less than the set peak cut target value P _cut , the centralized management device MC4 controls this to the peak cut target value P _cut . Therefore, depending on the detection interval of the interconnection point power P (t) and the calculation interval of the suppression index pr _PV and the charge / discharge index pr _B , the peak cut target value P _cut or less is instantaneously obtained. Therefore, when setting the upper limit value of the purchased power, it is preferable to set a value smaller than the upper limit value desired by the user by a predetermined amount. As a result, the peak cut target value P _cut is set to a value larger than the actual target value, so that even if the interconnection point power P (t) drops instantaneously, it will be equal to or less than the peak cut target value P _cut. It can be suppressed.

From the above, according to the solar power generation system PVS4 according to the present embodiment, as the target power of the interconnection point power P (t), when using a peak cut target value P _cut instead of the output command value P ^C Even so, the interconnection point power P (t) can be made to match the target power (peak cut target value P _cut ). Further, since each power conditioner PCS _PVi and PCS _Bk obtain the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the processing load of the centralized management device MC4 can be reduced.

In the fourth embodiment, since the discharge of the storage battery B _k is prioritized during the peak cut control, the electric power stored in the storage battery B _k is reduced. Therefore, when a predetermined charging condition is satisfied, a part of the electric power supplied from the electric power system A may be used to charge the storage battery B _k . Examples of such a charging condition include a case where the interconnection point power P (t) is larger than the peak cut target value P _cut by a threshold value or more. By doing so, the storage battery B _k can be charged in preparation for the next peak cut control.

In such charge control of the storage battery B _k , the presence / absence of charging and the charging speed may be changed at predetermined time zones. For example, the charging mode can be set for each predetermined time zone. Then, the charging of the storage battery B _k is controlled according to the charging mode. Such charging modes include, for example, no charging mode, normal charging mode, and low speed charging mode. The no-charge mode is a mode in which charging is not performed. The normal charging mode is a mode for charging at a predetermined charging speed (normal speed). The low-speed charging mode is a mode for charging at a predetermined speed (low speed) slower than the normal speed. The charging mode is not limited to these. The user can set the charging mode by the user interface of the centralized management device MC4 or the like, and the mode setting unit (not shown) sets the charging mode according to the user's operation instruction. The predetermined time zone is a predetermined period in which one day is divided into a plurality of time zones. For example, when the day is divided into a plurality of time zones, it can be set for each of 24 time zones, and is divided into every 30 minutes. In the case, it can be set for each of 48 time zones. In addition, it may be divided into time zones such as morning, noon, evening, evening, and midnight. Further, a predetermined time zone may be provided not on a daily basis but on a weekly basis.

Specifically, the centralized management device MC4 transmits the charging mode setting information set by the mode setting unit to each of the power conditioner PCS _Bk via the transmission unit 24'. Then, each power conditioner PCS _Bk that receives this via the receiving unit 31 uses the charging rate C _rate ^M associated with the set charging mode to store the storage battery B shown in the above equation (20c'). Change the C rate constraint of _k (charge rated output _PSMk ^lmt ). For example, the charge rate C _rate ^M for the normal charge mode is set to 0.3, the charge rate C _rate ^M for the low speed charge mode is set to 0.1, and the charge rate C _rate ^M for the no charge mode is set to 0. .. Then, each power conditioner PCS _Bk obtains an individual target power P _Bk ^ref based on the optimization problem shown in the above equation (20'), so that the storage battery B _k is charged or not according to the charge mode setting. And the charging speed can be changed. The charging speed may be changed so that the storage battery B _k is fully charged in the time zone in which the low-speed charging mode is continuously set. For example, when the "low-speed charging mode" is continuously set from midnight to 6:00 am, the charging speed is set so that the storage battery B _k is fully charged over 6 hours. Specifically, the charge rate C _rate ^{M is set} to 1/6 (≈0.167). However, it is desirable not to exceed the normal speed. By doing so, it is possible to appropriately change whether or not the storage battery B _k is charged and the charging speed according to the charging mode. Therefore, when the power unit price of the above-mentioned pay-as-you-go rate (of power purchase) changes depending on the time zone, for example, the power purchase is increased during the time when the power unit price is low, and the power purchase is performed during the time when the power unit price is high. The power can be reduced.

In the fourth embodiment, the case where a plurality of power conditioners PCS _PVi to which the solar cell SP _i is connected is provided as an example has been described, but these may not be provided. That is, it may be composed of a plurality of power conditioner PCS _Bk to which the storage battery B _k is connected, the power load L, and the centralized management device MC4.

Next, the photovoltaic power generation system PVS5 according to the fifth embodiment will be described. The overall configuration of the photovoltaic power generation system PVS5 is substantially the same as that of the photovoltaic power generation system PVS3 (see FIG. 17) according to the third embodiment, and the illustration thereof will be omitted. In the third embodiment, it was possible to reverse power flow, but in the fifth embodiment, reverse power flow is prohibited.

In the photovoltaic power generation system PVS5 in which reverse power flow is prohibited, it is necessary to provide a reverse power relay 51 at the interconnection point to the power system A. The reverse power relay 51 is a kind of relay. When the reverse power relay 51 detects that a reverse power flow has occurred in the power system A from the photovoltaic power generation system PVS5, the photovoltaic power generation system PVS5 is disconnected from the power system A. For example, the reverse power relay 51 detects the interconnection point power P (t) and detects the occurrence of reverse power flow based on the interconnection point power P (t). Then, when the occurrence of reverse power flow is detected, the photovoltaic power generation system PVS5 is disconnected from the power system A by shutting off a circuit breaker (not shown) provided at the interconnection point. Once the line is broken, it takes time to return because it is necessary to call a specialized contractor. For example, when the power load L is low due to a factory suspension day or the like, the power consumption of the power load L decreases. Therefore, if the weather is sunny in the factory of the rest day, there is a case where power generation amount P _i ^SP of solar cells SP _i is greater than the power consumption of the power load L, this time, the reverse flow occurs.

Therefore, in the photovoltaic power generation system PVS5 according to the fifth embodiment, the power conditioners PCS _PVi and PCS _Bk are distributedly controlled by using the suppression index pr _PV and the charge / discharge index pr _B to generate reverse power flow. Suppress. This is called "reverse power flow avoidance control". When the interconnection point power P (t) is a positive value, reverse power flow is generated. Therefore, in order to suppress the occurrence of reverse power flow, the interconnection point power P (t) is a positive value. The negative value should be maintained so that it does not become. The photovoltaic power generation system PVS5 suppresses the individual output power P _PVi ^out of each power conditioner PCS _PVi in reverse power flow avoidance control. Further, to charge the battery B _k controls the individual output power P _Bk ^out of the power conditioner PCS _Bk. In this way, electric power is constantly supplied from the electric power system A to the photovoltaic power generation system PVS5. Therefore, the interconnection point power P (t) is maintained at a negative value so that it does not become a positive value. As a result, the occurrence of reverse power flow is suppressed.

FIG. 20 shows the functional configuration of the control system related to reverse power flow avoidance control of the photovoltaic power generation system PVS5. In FIG. 20, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. As a control system for reverse power flow avoidance control, the photovoltaic power generation system PVS5 includes a centralized management device MC5 instead of the centralized management device MC3 as compared with the photovoltaic power generation system PVS3 according to the third embodiment. It differs in that.

In the centralized management device MC5, the target power setting unit 21 sets the reverse power flow avoidance target value P _RPR for suppressing the occurrence of reverse power flow as the target power. This reverse power flow avoidance target value P _RPR is a target value of the interconnection point power P (t) and is a negative value. The reverse power flow avoidance target value P _RPR can be freely specified by the user. The target power setting unit 21 outputs the set target power (reverse power flow avoidance target value P _RPR ) to the index calculation unit 23'.

Further, in the centralized management device MC5, the index calculation unit 23'uses the interconnection point power P (t) and the reverse power flow avoidance target value _PRPR input from the target power setting unit 21 to suppress the suppression index pr _PV. And the charge / discharge index pr _B is calculated. That is, in the present embodiment, the index calculation unit 23'calculates the suppression index pr _PV and the charge / discharge index pr _{B for} setting the interconnection point power P (t) to the reverse power flow avoidance target value P _RPR . Specifically, the index calculation unit _{23'calculates} the Lagrange multiplier λ by using the reverse power flow avoidance target value P _{RPR R} instead of the output command value P ^C (t) in the above equation (21). Then, the Lagrange multiplier λ calculated by the above equation (22) is calculated as a suppression index pr _PV and a charge / discharge index pr _B. The index calculation unit 23'transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 24'. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 24'.

In the photovoltaic power generation system PVS5 configured in this way, the centralized management device MC5 monitors the interconnection point power P (t) detected by the interconnection point power detection unit 22. Then, when the interconnection point power P (t) becomes equal to or higher than the reverse power flow avoidance target value P _RPR , the index calculation unit 23'sets the interconnection point power P (t) to the reverse power flow avoidance target value P _RPR. The suppression index pr _PV and the charge / discharge index pr _B are calculated. Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref based on the optimization problem using the suppression index pr _PV calculated by the centralized management device MC5, and sets the individual output power P _PVi ^out as the individual target power. Control to P _PVi ^ref . Further, each power conditioner PCS _Bk calculates the individual target power P _Bk ^ref based on the optimization problem using the charge / discharge index pr _B calculated by the centralized management device MC5, and sets the individual output power P _Bk ^out . Control to individual target power P _Bk ^ref . As a result, the interconnection point power P (t) is controlled to the reverse power flow avoidance target value P _RPR to suppress the occurrence of reverse power flow. That is, the reverse power relay 51 is suppressed from operating due to the reverse power flow.

When the set value of the reverse power flow avoidance target value _PRPR is 0 (or close to 0), it depends on the detection interval of the interconnection point power P (t) and the calculation interval of the suppression index pr _PV and the charge / discharge index pr _B. When the interconnection point power P (t) rises instantaneously, the interconnection point power P (t) becomes a positive value, and reverse power flow may occur. Therefore, the set reverse power flow avoidance target value P _RPR should be set to a value smaller than 0 by a predetermined amount. As a result, the reverse power flow avoidance target value P _RPR becomes smaller than 0, so that even if the interconnection point power P (t) rises instantaneously, it can be suppressed from exceeding 0. Therefore, it is possible to suppress the occurrence of reverse power flow.

From the above, according to the solar power generation system PVS5 according to the present embodiment, as the target power of the interconnection point power P (t), using a reverse power flow avoidance target value P _RPR instead of the output command value P ^C Even in this case, the interconnection point power P (t) can be matched with the target power (reverse power flow avoidance target value _PRPR ). Further, since each power conditioner PCS _PVi and PCS _Bk obtain the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the processing load of the centralized management device MC5 can be reduced.

In the fifth embodiment, since charging of the storage battery B _k is prioritized during reverse power flow avoidance control, electric power is stored in the storage battery B _k . Therefore, the storage battery B _k may be discharged when a predetermined discharge condition is satisfied. Examples of such a discharge condition include a case where the interconnection point power P (t) is smaller than the reverse power flow avoidance target value P _RPR by a threshold value or more. By doing so, the storage battery B _k can be discharged in preparation for the next reverse power flow avoidance control.

In such discharge control of the storage battery B _k , whether or not to discharge may be changed at each predetermined time zone. For example, the discharge mode can be set for each of the predetermined time zones. Then, it controls whether or not to discharge the storage battery B _k according to the discharge mode. Such a discharge mode includes, for example, a discharge mode and a discharge non-discharge mode. The discharge-existing mode is a mode in which discharge is performed. The no-discharge mode is a mode in which no discharge is performed. The discharge mode is not limited to these. The user can set the discharge mode by using the user interface of the centralized management device MC5 or the like, and a mode setting unit (not shown) sets the discharge mode according to the user's operation instruction. The predetermined time zone at this time may be the same as or different from the predetermined time zone in the peak cut control.

Specifically, the centralized management device MC5 transmits the discharge mode setting information set by the mode setting unit to each of the power conditioner PCS _Bk via the transmission unit 24'. Then, each power conditioner PCS _Bk that receives the power conditioner PCS _Bk via the receiving unit 31 uses the discharge rate C _rate ^P associated with the set discharge mode, and the storage battery B shown in the above equation (20c') Change the C rate constraint of _k (discharge rated output P _SPk ^lmt ). For example, 0.3 is the discharge rate C _rate ^P to the discharge chromatic mode, the discharge rate C _rate ^P to the discharge-free mode is set to 0, respectively. Then, whether the power conditioner PCS _Bk is the (20 ') on the basis of the optimization problem shown in equation by obtaining the individual target power P _Bk ^ref, discharging the storage battery B _k in accordance with the setting of the discharge mode Can be changed. By doing so, it is possible to appropriately change whether or not to discharge the storage battery B _k according to the discharge mode. Therefore, it is possible to store electric power without discharging the storage battery B _k as needed.

In the fifth embodiment, the reverse power relay 51 describes the case where the photovoltaic power generation system PVS5 is disconnected from the power system A, but the present invention is not limited to this. For example, each power conditioner PCS _PVi and PCS _Bk may be _disconnected from the power system A. That is, even if the reverse power relay 51 disconnects, the power load L may remain connected to the power system A. For example, the circuit breaker is installed at the position BP1 of the connection line shown in FIG. 20 or at the position BP2 of the connection line shown in FIG. 20 (each near the output end of each power conditioner PCS _PVi and PCS _Bk ). As a result, the reverse power relay 51 can _disconnect the power conditioners PCS _PVi and PCS _Bk from the power system A while leaving the power load L.

In the above-described fifth embodiment, the case where a power conditioner PCS _Bk of multiple storage battery B _k are connected has been described as an example, it may not include them. That is, it may be composed of a plurality of power conditioners PCS _PVi to which the solar cell SP _i is connected, a power load L, and a centralized management device MC5. In this case, when the photovoltaic power generation system PVS5 performs reverse power flow avoidance control, the reverse power flow in which the interconnection point power P (t) is set is only suppressed by suppressing the individual output power P _PVi ^out from the power conditioner PCS _PVi. The avoidance target value is P _RPR .

In the third to fifth embodiments, the photovoltaic power generation systems PVS3, PVS4, and PVS5 in which the output suppression control, the peak cut control, and the reverse power flow avoidance control are individually implemented have been described, but various controls thereof are described. It is also possible to combine them. In this case, the centralized management device may appropriately switch which control is performed. For example, it may be switched according to the user's operation, the situation (positive / negative of interconnection point power P (t) (whether or not reverse power flow is in progress), reverse power flow is prohibited, or power of power load L. It may be switched automatically according to the consumption history, working days, etc.).

Next, the photovoltaic power generation system PVS6 according to the sixth embodiment will be described. In the first to fifth embodiments, the interconnection point power P (t) detected by the interconnection point power detection unit 22 is regarded as the output power of the entire photovoltaic power generation systems PVS1 to PVS5. However, not limited to the interconnection point power P (t), the individual output powers P _i ^out or the individual output powers P _PVi ^out and P _Bk ^out from each power conditioner PCS _i or each power conditioner PCS _PVi and PCS _Bk , respectively. It is also possible to calculate the total (hereinafter referred to as "total system output") and regard this as the output power of the entire photovoltaic power generation system. Therefore, the photovoltaic power generation system PVS6 is controlled so that the total output of the system becomes the target power. Therefore, the total system output is used as the power to be adjusted.

FIG. 21 shows the overall configuration of the photovoltaic power generation system PVS6. As shown in FIG. 21, the photovoltaic power generation system PVS6 includes a plurality of solar cells SP _i , a plurality of power conditioners PCS _PVi , and a plurality of units. It is composed of a storage battery B _k , a plurality of power conditioners PCS _Bk , and a centralized management device MC6.

The photovoltaic power generation system PVS6 according to the sixth embodiment does not detect the interconnection point power P (t), and is the sum of all the individual output powers P _PVi ^out and P _Bk ^out of each power conditioner PCS _PVi and PCS _Bk. (System total output P _total (t)) is calculated. Then, the total output P _total (t) of the system is controlled to match the output command value P ^C instructed by the electric power company as the output power of the entire photovoltaic power generation system PVS6. That is, the photovoltaic power generation system PVS6 performs output suppression control using the system total output P _total (t) instead of the interconnection point power P (t).

FIG. 22 shows the functional configuration of the control system related to the output suppression control of the photovoltaic power generation system PVS6 shown in FIG. In FIG. 22, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. The photovoltaic power generation system PVS6 is different in that the centralized management device MC6 is provided as the control system for the output suppression control in place of the centralized management device MC2 according to the second embodiment. In addition, the configurations of each power conditioner PCS _PVi and PCS _Bk are also different.

In the present embodiment, each power conditioner PCS _PVi further includes an output power detection unit 14 and a transmission unit 15, and each power conditioner PCS _Bk further includes an output power detection unit 34 and a transmission unit 35, respectively. I have. Further, the centralized management device MC6 includes a receiving unit 61, a total output calculation unit 62, and an index calculation unit 63 instead of the interconnection point power detection unit 22 and the index calculation unit 23'.

The output power detection unit 14 is provided in each power conditioner PCS _PVi , and detects the individual output power P _PVi ^out of the own device. The output power detection unit 34 is provided in each power conditioner PCS _Bk , and detects the individual output power P _Bk ^out of the own device.

The transmission unit 15 transmits the individual output power P _PVi ^out detected by the output power detection unit 14 to the centralized management device MC6. The transmission unit 35 transmits the individual output power P _Bk ^out detected by the output power detection unit 34 to the centralized management device MC6.

The receiving unit 61 receives the individual output powers P _PVi ^out and P _Bk ^out transmitted from the power conditioners PCS _PVi and PCS _Bk .

The total output calculation unit 62 calculates the system total output P _total (t), which is the sum of the individual output powers P _PVi ^out and P _Bk ^out received by the reception unit 61. In the present embodiment, the total output calculation unit 62 calculates the system total output P _total (t) by adding all the input individual output powers P _PVi ^out and P _Bk ^out .

The index calculation unit 63 calculates an index for using the system total output P _total (t) calculated by the total output calculation unit 62 as the target power. In the present embodiment, since the output command value P ^C is input as the target power, the index calculation unit 63 sets the suppression index pr _PV and the charge for setting the _total system output P _total (t) to the output command value P ^C. The discharge index pr _B is calculated. At this time, the index calculation unit 63 calculates the Lagrange multiplier λ by using the system total output P _total (t) instead of the interconnection point power P (t) in the above equation (21). Then, the Lagrange multiplier λ calculated by the above equation (22) is calculated as a suppression index pr _PV and a charge / discharge index pr _B. The calculated suppression index pr _PV is transmitted to each power conditioner PCS _PVi via the transmission unit 24'. Further, the calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk via the transmission unit 24'.

According to the photovoltaic power generation system PVS6 according to the present embodiment, the _total system output P _total (t) is used instead of the interconnection point power P (t) in the second embodiment as the power to be adjusted. also, it is possible to total system output P _total (t) to the target power (output command value P ^C). Further, since each power conditioner PCS _PVi and PCS _Bk obtain the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner, the processing load of the centralized management device MC6 can be reduced.

In the above-described sixth embodiment, with respect to solar power generation system PVS2 according to the second embodiment, a case has been described for controlling the output command value P ^C total system output P _total (t) as an example, the first The same may be applied to the photovoltaic power generation system PVS1 according to the embodiment. That is, in the photovoltaic power generation system PVS1 according to the first embodiment, even when controlling system total output P _total (t) to the output command value P ^C in place of interconnection point power P (t), the suppression indicators pr It can be used to control output suppression. Again, while the system total output P _total (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device.

Next, the photovoltaic power generation system PVS7 according to the seventh embodiment will be described. The same or similar items as those in the sixth embodiment are designated by the same reference numerals, and the description thereof will be omitted. FIG. 23 shows the overall configuration of the photovoltaic power generation system PVS7. As shown in the figure, the photovoltaic power generation system PVS7 includes a plurality of solar cells SP _i , a plurality of power conditioner PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioner PCS _Bk , and a centralized management device. It is configured to have MC7 and a power load L. Therefore, it differs from the photovoltaic power generation system PVS6 according to the sixth embodiment in that it further includes a power load L.

FIG. 24 shows the functional configuration of the control system related to the output suppression control of the photovoltaic power generation system PVS7 shown in FIG. In FIG. 24, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. As shown in the figure, the configurations of the power conditioners PCS _PVi and PCS _{Bk according} to the seventh embodiment and the centralized management device MC7 are the power conditioners PCS _PVi and PCS _{Bk according} to the sixth embodiment. The configuration is the same as that of the centralized management device MC6 (see FIG. 22).

Also in the photovoltaic power generation system PVS7 according to the present embodiment, as in the sixth embodiment, the output using the suppression index pr _PV and the charge / discharge index pr _B based on the calculated _total system output P _total (t). Suppression control can be performed. Therefore, as in the sixth embodiment, while the system total output P _total (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device MC7.

In the seventh embodiment, the case where the power load L is added to the photovoltaic power generation system PVS6 according to the sixth embodiment has been described as an example, but the power load L has been described with respect to the photovoltaic power generation system PVS1. Add a, and, even in the solar power generation system that controls the output command value P ^C total system output P _total (t) instead of interconnection point power P (t), by using the suppression indicators pr, output Suppression control can be performed. Again, with the total system output P _total (t) to the target power (output command value P ^C), it is possible to reduce the processing load of the central control device.

Next, the photovoltaic power generation system PVS8 according to the eighth embodiment will be described. The overall configuration of the photovoltaic power generation system PVS8 is substantially the same as that of the photovoltaic power generation system PVS7 (see FIG. 23) according to the seventh embodiment. In the sixth and seventh embodiments, various target powers are set for the _total system output P _total (t), but in the present embodiment, a plurality of power conditioners are divided into a plurality of groups. , The target power is set for each group. In the following description, a plurality of power conditioners PCS _PVi, the PCS _Bk, is a set of a plurality of solar cells PCS group is a set of power conditioner PCS _PVi G _PV and a plurality of power conditioners PCS _Bk a case in which divided into two groups of battery PCS group G _B will be described.

Photovoltaic system PVS8 according to the eighth embodiment, in the solar cell PCS group G _PV with the above battery PCS group G _B, respectively set the target power, the total output power and battery PCS solar cell PCS group G _PV the total output power of the group G _B is controlled to respectively become the target power. This control is called "schedule control". The total output power of the solar cell PCS group G _PV is the sum .SIGMA.P _PVi ^out individual output power P _PVi ^out of the power conditioner PCS _PVi, hereinafter referred to as solar cell PCS group total output P _GPV. The total output power of the battery PCS group G _B is the sum .SIGMA.P _Bk ^out of individual output power P _Bk ^out of the power conditioner PCS _Bk, hereinafter referred to as battery PCS group total output P _GB.

FIG. 25 shows the functional configuration of the control system related to the schedule control of the photovoltaic power generation system PVS8. In FIG. 25, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. The control system related to the schedule control differs from the photovoltaic power generation system PVS7 according to the seventh embodiment in the following points. That is, the centralized management device MC8 includes a total output calculation unit 62'instead of the total output calculation unit 62, and an index calculation unit 63'instead of the index calculation unit 63.

In the centralized management device MC8, the target power setting unit 21 sets the target value of the solar cell PCS group total output P _GPV , which is the target value of the solar cell PCS group target value P _TPV, and the target value of the storage battery PCS group total output P _GB. The group target value P _TB is set as the target power. Solar PCS group target value P _TPV and accumulators PCS group target value P _TB can be set for each of the predetermined time period. These target values can be freely specified by the user. The target power setting unit 21 outputs the set target power (solar cell PCS group target value P _TPV and storage battery PCS group target value P _TB ) to the index calculation unit 63'.

The total output calculation unit _{62'calculates the} total output P _GPV of the solar cell PCS group and the total output P _GB of the storage battery PCS group, respectively. Specifically, the total output calculation unit _62'adds the individual output power P _PVi ^out of the power conditioner PCS _PVi received by the reception unit 61, and calculates the total output P _GPV of the solar cell PCS group. Further, the total output calculation unit _62'adds the individual output power P _Bk ^out of the power conditioner PCS _Bk received by the reception unit 61, and calculates the total output P _GB of the storage battery PCS group.

The index calculation unit _63'is a suppression index pr for _{converting the} total output P _GPV of the solar cell PCS group calculated by the total output calculation unit _{62'to the} target value P _TPV of the solar cell PCS group input from the target power setting unit 21. Calculate _PV . At this time, the index calculation unit 63'calculates the suppression index pr _PV using the following equation (34). In the following equation (34), λ _PV indicates the Lagrange multiplier for a plurality of power conditioner PCS _PVi , and ε _PV indicates the gradient coefficient for a plurality of power conditioner PCS _PVi . Further, since the total output of the solar cell PCS group P _GPV and the target value P _TPV of the solar cell PCS group are values that change with time t, the total output of the solar cell PCS group is P _GPV (t) and the solar cell PCS group, respectively. The target value is described as P _TPV (t). Thus, the index calculation unit 63 'is, instead of the above in (9), a solar cell PCS group total output P _GPV (t) instead of interconnection point power P (t), the output command value P ^C (t) The Lagrange multiplier λ _PV is calculated using the solar cell PCS group target value P _TPV (t). Then, the calculated Lagrange multiplier λ _PV is used as the suppression index pr _PV . The index calculation unit 63'transmits the calculated suppression index pr _PV to each power conditioner PCS _PVi via the transmission unit 24'.

Further, the index calculation unit 63'is a charge / discharge index for converting the total output P _GB of the storage battery PCS group calculated by the total output calculation unit 62'to the target value P _TB of the storage battery PCS group input from the target power setting unit 21. Calculate pr _B. At this time, the index calculation unit 63'calculates the charge / discharge index pr _B using the following equation (35). In the following equation (35), λ _B indicates a Lagrange multiplier for a plurality of power conditioner PCS _Bk , and ε _B indicates a gradient coefficient for a plurality of power conditioner PCS _Bk . Further, since the storage battery PCS group total output P _GB and the storage battery PCS group target value P _TB are values that change with time t, the storage battery PCS group total output is P _GB (t) and the storage battery PCS group target value is P, respectively. It is described as _TB (t). Thus, the index calculation unit 63 ', in the above-mentioned (9), the storage battery PCS group total output P _GB (t) instead of interconnection point power P (t), instead of the output command value P ^C (t) The Lagrange multiplier λ _B is calculated using the storage battery PCS group target value P _TB (t). Then, the calculated Lagrange multiplier λ _B is used as the charge / discharge index pr _B. The index calculation unit 63'transmits the calculated charge / discharge index pr _B to each power conditioner PCS _Bk via the transmission unit 24'.

In the photovoltaic power generation system PVS8 configured in this way, the centralized management device MC8 obtains the individual output power P _PVi ^out from each power conditioner PCS _PVi and calculates the total output P _GPV of the solar cell PCS group. Then, the suppression index pr _PV is calculated using the above equation (34) so that the calculated total output P _GPV of the solar cell PCS group becomes the target value P _{TPV of the} solar cell PCS group. The calculated suppression index pr _PV is transmitted to each power conditioner PCS _PVi . Each power conditioner PCS _PVi calculates the individual target power P _PVi ^ref by using the received suppression index pr _PV , and controls so that the individual output power P _PVi ^out becomes the individual target power P _PVi ^ref . Further, the centralized management device MC8 obtains the individual output power P _Bk ^out from the power conditioner PCS _Bk, and calculates the total output P _GB of the storage battery PCS group. Then, the charge / discharge index pr _B is calculated using the above equation (35) so that the calculated total output P _GB of the storage battery PCS group becomes the target value P _{TB of the} storage battery PCS group. The calculated charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk . Each power conditioner PCS _Bk calculates an individual target power P _Bk ^ref using the received charge / discharge index pr _B , and controls so that the individual output power P _Bk ^out becomes the individual target power P _Bk ^ref . As a result, the total output P _GPV of the solar cell PCS group becomes the target value P _{TPV of the} solar cell PCS group, and the total output P _GB of the storage battery PCS group becomes the target value P _{TB of the} storage battery PCS group.

From the above, according to the solar power generation system PVS8 according to the present embodiment, the solar cell PCS group G _PV and accumulators PCS group G _B every target power (solar PCS group target value P _TPV and accumulators PCS group target value P _TB ) can be set so that the total output P _GPV of the solar cell PCS group is set to the target value P _TPV of the solar cell PCS group, and the total output P _GB of the storage battery PCS group is set to the target value P _TB of the storage battery PCS group. Further, since the power conditioners PCS _PVi and PCS _Bk calculate the individual target powers P _PVi ^ref and P _Bk ^ref in a distributed manner based on the suppression index pr _PV and the charge / discharge index pr _B , respectively, the centralized management device MC8 The processing load can be reduced.

In the above-described eighth embodiment, illustrating a case of setting the solar cell PCS group G _PV and accumulators PCS group G _B every target power (solar PCS group target value P _TPV and accumulators PCS group target value P _TB) as an example However, only one of them may be used.

Set of the in the eighth embodiment, a plurality of power conditioners PCS _PVi, PCS _Bk a plurality and solar PCS group G _PV table is a set of a plurality of power conditioners PCS _PVi power conditioner PCS _Bk a case in which divided into two groups with the battery PCS group G _B is described as an example is, but is not limited thereto. For example, the solar cell PCS group _GPV may be further divided into a plurality of groups, and the target power may be set for each group. The same applies to the storage battery PCS group G _B. Further, the target power may be set for each group by grouping so that one group includes both one or more power conditioner PCS _PVi and one or more power conditioner PCS _Bk. .. In this case, the suppression index pr _PV and the charge / discharge index pr _B may be calculated for each group using the above equations (21) and (22).

In the eighth embodiment, the case of dividing into a plurality of groups has been described, but the schedule may be controlled by using a plurality of power conditioners PCS _PVi and PCS _Bk as one group without dividing into a plurality of groups. .. That is, the user is free to set the target value of the total system output P _total (t) every predetermined time period, the system total output P _total (t) of may be controlled so as to coincide to the target value. When schedule control is performed as one group in this way, the interconnection point power P (t) may be used instead of the system total output P _total (t). That is, in the photovoltaic power generation systems PVS1 to PVS5 according to the first embodiment to the fifth embodiment, the target value of the interconnection point power P (t) is freely set as the target power for each predetermined time zone. , The interconnection point power P (t) may be made to match the target value.

Although the photovoltaic power generation systems PVS7 and PVS8 in which the output suppression control and the schedule control are individually implemented have been described in the seventh embodiment and the eighth embodiment, respectively, these can be combined. In this case, the centralized management device may appropriately switch which control is performed. For example, it may be switched according to the operation of the user, or the situation (whether the suppression instruction is received from the electric power company, whether the solar cell PCS group target value _PTPV or the storage battery PCS group target value _PTB is set, etc. ) May be automatically switched.

In the seventh and eighth embodiments, the centralized management devices MC7 and MC8 are provided with a configuration in which the individual output powers P _PVi ^out and P _Bk ^out are obtained from the respective power conditioners PCS _PVi and PCS _Bk. Although described as an example, a configuration may be added in which the power consumption of the power load L is obtained from the power load L. When the power consumption of the power load L is available in this way, the sum of the individual output powers P _PVi ^out and P _Bk ^out obtained from each power conditioner PCS _PVi and PCS _Bk and the power consumption obtained from the power load L is calculated. By calculating, the interconnection point power P (t) can be estimated. Therefore, even if the interconnection point power detection unit 22 is not provided, the output suppression control according to the third embodiment, the peak cut control according to the fourth embodiment, and the reverse power flow avoidance according to the fifth embodiment are provided. Control can be performed.

In the third to fifth embodiments, the case where the output suppression control, the peak cut control, and the reverse power flow avoidance control are performed based on the interconnection point power P (t) will be described as an example, and the seventh embodiment will be described. In the embodiment and the eighth embodiment, the output suppression control and the schedule control are performed based on the system total output P _total (t), the solar cell PCS group total output P _GPV, and the storage battery PCS group total output P _GB , respectively. Each of these examples has been described, but is not limited to this. It is provided with both means for detecting the interconnection point power P (t) (interconnection point power detection unit 22) and means for obtaining individual output powers P _PVi ^out and P _Bk ^out from the power conditioners PCS _PVi and PCS _Bk , respectively. The output suppression control, the peak cut control, the reverse power flow avoidance control, and the schedule control may be combinedly controlled.

Next, the photovoltaic power generation system PVS9 according to the ninth embodiment will be described. FIG. 26 shows the overall configuration of the photovoltaic power generation system PVS9. As shown in the figure, the photovoltaic power generation system PVS9 includes a plurality of solar cells SP _i , a plurality of power conditioner PCS _PVi , a plurality of storage batteries B _k , a plurality of power conditioner PCS _Bk , and a centralized management device. It is configured to have MC9 and a power load L. Further, a demand monitoring device 91 is installed at the interconnection point between the photovoltaic power generation system PVS9 and the power system A. In the present embodiment, the storage battery PCS group G _B is formed by a plurality of power conditioners PCS _Bk. Each power conditioner PCS _PVi corresponds to the "solar cell power conditioner" of the present invention. Each power conditioner PCS _Bk corresponds to the "battery power conditioner" and "power supply device" of the present invention. The demand monitoring device 91 corresponds to the "power monitoring device" of the present invention. The one including the photovoltaic power generation system PVS9 and the demand monitoring device 91 corresponds to the "electric power system" of the present invention.

The demand monitoring device 91 is a device that monitors a demand value that determines a basic electricity rate and is used for reducing the electricity rate. For example, as such a demand monitoring device 91, there is one disclosed in the above-mentioned Patent Document 2. The demand monitoring device 91 calculates a demand value based on the electric power supplied from the electric power system A to the photovoltaic power generation system PVS9. That is, the demand monitoring device 91 calculates the demand value based on the demand power of the photovoltaic power generation system PVS9. The demand value is the average power demand for each demand period (generally 30 minutes). In the present embodiment, the demand value is assumed to be the average demand power per demand time period, but may be the cumulative demand power per demand time period. Of this average demand power (demand value), the largest value in a month is called the maximum demand power, and the largest value among the maximum demand power in each month in the past year (hereinafter referred to as "maximum demand value"). The contract power is determined based on. That is, the contract power is determined by the maximum demand value, and if the contract power is large, the basic charge is high, and if it is small, the basic charge is low. Therefore, in order to reduce the electricity bill, it is effective to suppress the maximum demand value and reduce the contracted power. The maximum demand value is substantially the same as the peak value in the fourth embodiment.

Therefore, the demand monitoring device 91 predicts the demand value at the end of the demand time limit, and the predicted demand value (hereinafter, referred to as “predicted demand value”) exceeds a preset target value (target demand value). When that happens, an alarm is issued. Specifically, the demand monitoring device 91 is connected to the interconnection point via a wattmeter and a pulse detector (not shown), and based on the pulse signal output from the pulse detector, the current demand value (hereinafter, hereinafter, demand value). "Current demand value") is calculated. The pulse signal is generated based on the amount of electric power supplied from the electric power system A. Next, the demand value (predicted demand value) at the end of the demand time limit is predicted based on the calculated current demand value. Then, the alarm level is specified based on the predicted demand value and the target demand value, and an alarm signal based on the alarm level is generated. Details of the alarm level will be described later. The target demand value may be set by the user and may be a value desired by the user, or may be a value based on the maximum demand value based on the contract power.

In the demand monitoring device according to Patent Document 2, the power consumption due to the power load L is reduced by stopping the power load L and shutting off the power load L based on the alarm signal. As a result, the power supplied from the power system A is reduced, and the maximum demand value is suppressed. However, in such a conventional method, when the power load L is, for example, an industrial machine in a factory, the industrial machine is stopped or the power supply line to the industrial machine is cut off, so that the work cannot be performed. The problem occurs. Therefore, the photovoltaic power generation system PVS9 according to the present embodiment receives an alarm signal from the demand monitoring device 91 and uses the electric power stored in the storage battery B _k without stopping the electric power load L or shutting off the electric power load L. It is supplied to the power load L. As a result, the power supplied from the power system A is reduced, and the maximum demand value is suppressed. This is called "demand monitoring device cooperation control".

FIG. 27 shows the functional configuration of the control system related to the demand monitoring device cooperative control of the photovoltaic power generation system PVS9 shown in FIG. In FIG. 27, the solar cell SP _i and the storage battery B _k are not shown. In addition, only the first power conditioners PCS _PVi and PCS _Bk are listed, respectively. The centralized management device MC9 has a contact signal receiving unit 92, a target power setting unit 21, a receiving unit 61, a total output calculation unit 62 ", an index calculation unit 63", and a transmission unit 24 in order to perform demand monitoring device cooperation control. 'Has.

The demand monitoring device 91 specifies four levels of alarm levels 1 to 4 based on the predicted demand value and the target demand value in the demand monitoring device linked control, and has four levels according to the specified alarm levels 1 to 4. The contact signals S1 to S4 are generated. That is, in the present embodiment, four-stage contact signals S1 to S4 are generated as the alarm signal. Specifically, the demand monitoring device 91 sets the alarm level 1 and the predicted demand value to the target demand value when the predicted demand value exceeds 50% of the target demand value based on the predicted demand value and the target demand value. Warning level 2 when the predicted demand value exceeds 80%, warning level 3 when the predicted demand value exceeds 100% of the target demand value, and warning level 4 when the predicted demand value exceeds 110% of the target demand value. To identify. That is, the alarm level 1 and the alarm level 2 are alarm levels for notifying that the demand value may exceed the target demand value, and the alarm level 3 and the alarm level 4 are for notifying that the demand value exceeds the target demand value. The alarm level is set. The value is not limited to these values. Then, the demand monitoring device 91 switches a plurality of contacts (not shown) according to the specified alarm levels 1 to 4, and generates any one of the contact signals S1 to S4 (alarm signal) by switching the plurality of contacts. To do. The demand monitoring device 91 transmits the generated contact signals S1 to S4 (alarm signals) to the centralized management device MC9 by wireless communication or wired communication. The number of alarm level steps and the number of contact signal steps are not limited to those described above. For example, the alarm may be given only when the predicted demand value exceeds the target demand value. That is, the alarm level may be one level. Further, the number of steps of the alarm level and the number of steps of the contact signal may be different.

The contact signal receiving unit 92 receives the contact signal transmitted from the demand monitoring device 91. The contact signal receiving unit 92 outputs the received contact signal to the target power setting unit 21. The contact signal receiving unit 92 corresponds to the "alarm signal receiving means" of the present invention.

In the central control device MC9, the target power setting unit 21 sets the discharge target value P _D corresponding to the contact signal as the target power. This discharge target value P _D is a target value for the total output P _GB of the storage battery PCS group. When battery PCS group total output P _GB is positive, since the power to the interconnection point side from the battery PCS group G _B is output, the discharge target value P _D is a positive value. Specifically, the target power setting unit 21 _acquires the discharge rated output P _SPk ^lmt of each storage battery B _k from each power conditioner PCS _Bk, and the total value of each discharge rated output P _SPk ^lmt (hereinafter, It is called "discharge output limit".) ΣP _SPk ^lmt is calculated. Then, the discharge target value P _D is set based on the contact signal input from the contact signal receiving unit 92 and the discharge output limit ΣP _SPk ^lmt . For example, to 0% of the discharge power limit .SIGMA.P _SPk ^lmt the discharge target value P _D Without contact signal. That is, the discharge target value P _D is set to 0. 25% of the discharge power limit .SIGMA.P _SPk ^lmt if contact signal S1, the discharge target value P _D. 50% of the discharge power limit .SIGMA.P _SPk ^lmt if contact signal S2, the discharge target value P _D. If contact signal S3, 75% of the discharge power limit .SIGMA.P _SPk ^lmt the discharge target value P _D. 100% of the discharge power limit .SIGMA.P _SPk ^lmt if contact signal S4, the discharge target value P _D. That is, the target power setting unit 21 sets the discharge target value P _D at a ratio to the discharge output limit ΣP _SPk ^lmt according to the received contact signal. The target power setting unit 21 transmits the set target power (discharge target value P _D ) to the index calculation unit 63 ”. In the present embodiment, when there is no contact signal, the discharge target value P _D is set to 0. However, nothing may be done. That is, the target power setting unit 21 does not set the discharge target value P _D when there is no contact signal, and sets the discharge target value P _D when there is a contact signal. it may be set. the setting value of the discharge target value P _D corresponding to the contact signal is not limited to those described above. for example, in response to the contact signal, and to an arbitrary value that is set in advance May be good.

The total output calculation unit 62 "calculates the total output P _GB of the storage battery PCS group. Specifically, the total output calculation unit 62" calculates the individual output power P _{Bk of} each power conditioner PCS _Bk received by the reception unit 61. Add ^out to calculate the total output P _GB of the storage battery PCS group. The total output calculation unit 62 "outputs the calculated total output P _GB of the storage battery PCS group to the index calculation unit 63".

Index calculating unit 63 ", the total output calculating section 62" and the storage battery PCS group total output P _GB which is calculated on the basis of the discharge target value P _D of target power setting unit 21 has set, battery PCS group total output P _GB Is calculated as a charge / discharge index pr _B for setting the discharge target value P _D. At this time, the index calculation unit 63 ”calculates the Lagrange multiplier λ _B by using the discharge target value P _D instead of the storage battery PCS group target value P _TB in the upper equation of the above equation (35). (35) by the lower expression of the equation to calculate the calculated Lagrange multiplier lambda _B as charge and discharge indicator pr _B. Note that the suppression indicators pr _PV, generated by the solar SP _i from the power conditioner PCS _PVi A fixed value "0" is used to maximize the power output. The index calculation unit 63 "outputs the suppression index pr _PV and the charge / discharge index pr _B to the transmission unit 24', whereby the transmission unit 24'transmits the suppression index pr _PV to each power conditioner PCS _PVi . The charge / discharge index pr _B is transmitted to each power conditioner PCS _Bk .

In such solar power generation systems PVS9 that is configured, the central control device MC9, based on the contact signal received from the demand monitoring device 91, sets the discharge target value P _D. Further, the centralized management device MC9 calculates the total output P _GB of the storage battery PCS group based on the individual output power P _Bk ^out received from each power conditioner PCS _Bk . Then, the charge / discharge index pr _B for matching the total output P _GB of the storage battery PCS group with the discharge target value P _D is calculated. Each power conditioner PCS _Bk calculates each individual target power P _Bk ^ref based on the optimization problem (equation (20) above) using the charge / discharge index pr _B. Then, the individual output power P _Bk ^out is controlled to the individual target power P _Bk ^ref . As a result, the total output P _GB of the storage battery PCS group matches the discharge target value P _D. As described above, since the discharge target value P _D is a positive value, the total output P _GB battery PCS group becomes a positive value, electric power from the storage battery PCS group G _B is output. At this time, the power conditioner PCS _Bk is discharged electric power accumulated in the storage batteries B _k. However, depending on the SOC of battery B _k is also storage batteries B _k which is not discharged. Power output from the battery PCS group G _B is consumed by the power load L. Therefore, the power supplied from the power system A to the photovoltaic power generation system PVS9 is reduced. Therefore, the target power (discharge target value P _D) can be said to be a value that reduces the supply power. This demand monitoring device cooperation control is repeatedly performed, and the power supply from the power system A decreases, so that the predicted demand value becomes equal to or less than the target demand value and the contact signal is not received from the demand monitoring device 91. That is, since the predicted demand value can be made equal to or less than the target demand value, the demand value (maximum demand value) can be suppressed. From this, it can be said that the charge / discharge index pr _B in the present embodiment is an index for making the demand value equal to or less than the target demand value.

FIG. 28 shows the simulation results when the demand monitoring device cooperation control is not performed and when it is performed. FIG. 28A shows a case where the demand monitoring device cooperation control is not performed. FIG. 28B shows a case where demand monitoring device cooperation control is performed. In each figure, the upper graph shows the temporal change of the current demand value (light solid line) and the predicted demand value (dark solid line), and the lower graph shows the interconnection point power P (t). ) Shows the temporal change. In the upper graph, the dotted line indicates the target demand value. In the simulation, the time change of the power consumption of the power load L shown in FIG. 29 (a) is assumed, and the time change of the power generation amount (total) of each solar cell SP _i shown in FIG. 29 (b). That is, the time change of the power output (ΣP _PVi ^out ) of each power conditioner PCS _PVi was assumed. Then, the target demand value was set to 2000 [kW].

Checking the upper graphs of both FIGS. 28 (a) and 28 (b), the current demand value is initialized (is 0) for each demand time period. In addition, the predicted demand value and the current demand value at the end of the demand time period match. Therefore, it can be confirmed that the current demand value and the predicted demand value are properly calculated.

Further, in the simulation, when the demand monitoring device cooperation control is not performed, the interconnection point power P (t) changes as shown in the lower part of FIG. 28 (a), and the current demand value is shown in the upper part of FIG. 28 (a). It was a change. At this time, as shown in the upper part of FIG. 28A, it can be seen that the current demand value (demand value) at the end of the demand time period exceeds the target demand value in the period T1. On the other hand, when the demand monitoring device linked control is performed, the interconnection point power P (t) changes as shown in the lower part of FIG. 28 (b), and the current demand value changes as shown in the upper part of FIG. 28 (b). .. At this time, as shown in the upper part of FIG. 28B, it can be seen that the current demand value (demand value) at the end of the demand time period does not exceed the target demand value in this simulation. Further, as shown in FIG. 28B, when the interconnection point power P (t) decreases in the period T1, the predicted demand value increases and becomes equal to or higher than the target demand value. At this time, since the contact signal is transmitted from the demand monitoring device 91, the demand monitoring device cooperation control is performed. As a result, the interconnection point power P (t) has increased, and the predicted demand value has decreased. Then, the current demand value (demand value) at the end of the demand time limit is equal to or less than the target demand value. That is, it can be seen that the demand value can be limited to the target demand value by the demand monitoring device cooperation control. From the results shown in FIGS. 28 (a) and 28 (b), when the demand monitoring device cooperation control is not performed, the demand value exceeds the target demand value in the period T1, whereas the demand monitoring device cooperation control is performed. When is performed, the demand value can be limited to the target demand value. Therefore, the demand value can be suppressed to the target demand value or less by performing the demand monitoring device linked control.

From the above, according to the solar power generation system PVS9 according to the present embodiment, based on the alarm signal transmitted from demand monitoring device 91 (contact signal), the central control device MC9 the target power (discharge target value P _D ) Is set, and the charge / discharge index pr _B for setting the total output P _GB of the storage battery PCS group to the discharge target value P _D is calculated. Further, each power conditioner PCS _Bk calculates each individual target power P _Bk ^ref by solving an optimization problem using the charge / discharge index pr _B. Then, the individual output power P _Bk ^out is controlled to the individual target power P _Bk ^ref . As a result, the total output P _GB of the storage battery PCS group becomes the discharge target value P _D. Thus, the central control device MC9 is not to calculate the individual target power P _Bk ^ref for each of the power conditioner PCS _Bk, using discharge indicator pr _B each power conditioner PCS _Bk receives from the central control device MC9 _Therefore , the individual target power P _Bk ^ref is calculated in a distributed manner. That is, since the centralized management device MC9 only calculates the charge / discharge index pr _B , the load on the centralized management device MC9 can be reduced. In addition, by the storage battery PCS group total output P _GB becomes the discharge target value P _D, power from the storage battery PCS group G _B is output. That is, the electric power stored in the storage battery B _k is supplied to the electric power load L. Therefore, since the electric power supplied from the electric power system A to the photovoltaic power generation system PVS9 can be reduced, the demand value (maximum demand value) can be suppressed.

In the ninth embodiment, since the storage battery B _k is discharged during the demand monitoring device linked control, the electric power stored in the storage battery B _k is reduced. Therefore, the storage battery B _k may be charged when the contact signal receiving unit 92 is not receiving the contact signal. For example, the target power setting unit 21 sets a charging target value (negative value), and the index calculation unit 63 "calculates the charge / discharge index pr _B for the total output P _GB of the storage battery PCS group to match the charging target value. The charging target value may be set arbitrarily, or may be set based on the SOC of the storage battery B _k , the difference between the target demand value and the predicted demand value, and the like. By doing so, the storage battery B _k can be charged when the contact signal is not received.

Further, the discharge mode and the charge mode may be set to be set for each predetermined time zone, and the control may be switched according to the set discharge mode or charge mode. For example, the centralized management device MC9 performs the above-mentioned demand monitoring device cooperation control when the discharge mode is set. On the other hand, when the charging mode is set, the centralized management device MC9 sets a charging target value and charges if there is no contact signal, and does nothing even if the contact signal is received. That is, the discharge is not performed during the charge mode. The discharge mode and the charge mode can be set by the user through the interface of the centralized management device MC9 or the like, and the mode setting unit (not shown) sets the discharge mode and the charge mode according to the operation instruction of the user. The target power setting unit 21 may set the mode instead of the mode setting unit. That is, the target power setting unit 21 may concurrently set the target power and the mode. By doing so, it is possible to discharge only the storage battery B _{k in} the discharge mode and only charge the storage battery B _{k in} the charge mode. Therefore, it is possible to separate the charging time from the discharging time. Can be done. Incidentally, the central control device MC9 is in the charging mode is not limited to the case that does nothing when it receives a contact signal in response to the contact signal received, so as to set the discharge target value P _D, as described above You may.

In the ninth embodiment, the demand monitoring device 91 has described the case where the alarm level is specified based on the predicted demand value and the target demand value, but the method for specifying the alarm level is not limited to this. For example, in addition to these predicted demand values and target demand values, the current demand value, adjusted power, reference power, and the like may be used to specify the alarm level. The adjusted power is the power that needs to be adjusted in order to keep the demand value below the target demand value. The adjusted power is calculated by (target demand value-current demand value) / remaining time within the demand time period x demand time period (30 minutes). The reference power is power calculated by multiplying the ratio of the target demand value to the demand time by the elapsed time from the start of the demand time (demand elapsed time). The reference power is calculated by target demand / demand time limit (30 minutes) × demand elapsed time. By using other information in this way, it is possible to predict whether or not the demand value exceeds the target demand value. In addition, when the predicted demand value exceeds the target demand, it is predicted how much the power supplied from the power system A can be reduced to keep the demand value at the end of the current demand time limit below the target demand. can do. Therefore, it is possible to specify the alarm level based on the amount of power that should reduce the power supplied from the power system A. Even when the demand monitoring device 91 specifies the alarm level as described above, the demand value can be limited to the target demand value by performing the demand monitoring device cooperation control by the photovoltaic power generation system PVS9.

In the ninth embodiment, the case where the demand monitoring device 91 generates one contact signal from the specified alarm level and transmits the one contact signal to the centralized management device MC9 has been described, but the present invention is not limited to this. That is, the demand monitoring device 91 may not only generate one contact signal but also generate a plurality of contact signals and transmit the generated one or a plurality of contact signals. In this case, the central control device MC9 receives one or more contact signals, based on the contact signal received, and sets the discharge target value P _D. For example, when receiving a plurality of contact signals, based on a combination of the received contact signal, it sets the discharge target value P _D. A specific method of such a modification will be described below.

The demand monitoring device 91 generates any one or a plurality (two to four) of the four contact signals S1 to S4 according to the specified alarm level by switching the plurality of contacts. Note that the contact signal may be generated based on the predicted demand value, the target demand value, or the like without specifying the alarm level. Then, the generated one or more contact signals are transmitted to the centralized management device MC9. In the centralized management device MC9, the contact signal receiving unit 92 receives one or a plurality of contact signals and sets a flag for the received contact signal (sets the flag to "1"). For example, it is assumed that flags F1 to F4 are provided corresponding to the contact signals S1 to S4, respectively. At this time, when only the contact signal S1 is received, only the flag F1 is set, and when the contact signals S1 and S2 are received, the flags F1 and F2 are set. Subsequently, the target power setting unit 21, based on the information of the flag of the contact signal receiving section 92 is erected, by adding a flag target value for the standing flag, a target power calculation value (discharge target value P _D) Set as. Flag target value is a previously set value corresponding to each flag is a value for calculating the discharge target value P _D. For example, it is assumed that 10 kW is set as the flag target value for the flag F1, 20 kW is set as the flag target value for the flag F2, 40 kW is set as the flag target value for the flag F3, and 80 kW is set as the flag target value for the flag F4. At this time, when the flags F1 and F2 are set as the flag information, 30 kW obtained by adding the flag target value 10 kW for the flag F1 and the flag target value 20 kW for the flag F2 is set as the discharge target value P _D. Also, if the flag F1 to F4 is standing all as information flags, the flag target value 10kW for each flag F1 to F4, 20 kW, 40 kW, it sets a 150kW obtained by adding all the 80kW as a discharge target value P _D. Such relationship between the state and the discharge target value P _D of the flags F1~F4 is a relationship as shown in Table 2 below. In Table 2 below, the states of the flags F1 to F4 are "1" when the flag is set and "0" when the flag is not set. When the discharge target value P _D is set by the target power setting unit 21, then the demand monitoring device cooperation control to above is performed. From the above, even when a plurality of contact signals are transmitted from the demand monitoring device 91 to the centralized management device MC9, the photovoltaic power generation system PVS9 can perform the demand monitoring device linked control. Also, the central control device MC9, since sets the discharge target value P _D by a combination of a plurality of contact signals to be received, it is possible to set the discharge target value P _D than the number of contact signals. The above values are examples, and the number of contact signals (flags), the value of the flag target value corresponding to the flag, and the like may be changed as appropriate.

In the above-described ninth embodiment, the central control device MC9, based on the contact signal received from the demand monitoring device 91, a case has been described for setting a discharge target value P _D, is not limited to this. For example, when the information of the warning level as an alarm signal from the demand monitoring device 91 is transmitted, the central control device MC9, based on of the warning level information may set the discharge target value P _D.

In the ninth embodiment, the demand monitoring device 91 measures the interconnection point power P (t), calculates the current demand value, predicts the predicted demand value, specifies the alarm level, and generates a contact signal (alarm signal). , And the case where the contact signal (alarm signal) is transmitted has been described as an example, but these may be performed by another external device. For example, the external device measures the interconnection point power P (t), calculates the current demand value, and predicts the predicted demand value, and the demand monitoring device 91 identifies the alarm level and generates a contact signal (alarm signal). And transmission may be performed. Further, the demand monitoring device 91 measures the interconnection point power P (t), calculates the current demand value, predicts the predicted demand value, and specifies the alarm level, and the external device generates a contact signal (alarm signal). And may be sent. In this way, the external device may appropriately perform the processing of the demand monitoring device 91.

In the ninth embodiment, the case where the photovoltaic power generation system PVS9 performs only the demand monitoring device cooperation control has been described, but the present invention is not limited to this. For example, in addition to the demand monitoring device cooperation control, the output suppression control according to the seventh embodiment may be performed. In this case, the total output calculation unit 62 "calculates the system total output P _total (t) in the same manner as the total output calculation unit 62, and outputs this to the index calculation unit 63". The target power setting unit 21 sets the output command value P ^C, which index calculating unit 63 'outputs a. The index calculation unit 63', similar to the index calculation unit 63, the system total output P _The suppression index pr _PV and the charge / discharge index pr _B are calculated based on the _total (t) and the output command value P ^C. As a result, output suppression control can also be performed. Similarly, the processing of the total output calculation unit 62'is added to the total output calculation unit 62", and the processing of the index calculation unit 63'is added to the index calculation unit 63 ". Then, the target power setting unit 21 sets the solar cell PCS group target value P _TPV and the storage battery PCS group target value P _TB to perform schedule control according to the eighth embodiment in addition to the demand monitoring device linked control. You can also do it. Further, the interconnection point power detection unit 22 is added to the centralized management device MC9, and the processing of the index calculation unit 23'is added to the index calculation unit 63 ". Then, the target power setting unit 21 adds the output command value P. By setting ^C , in addition to the demand monitoring device linked control, the output suppression control according to the third embodiment can be performed. Further, the target power setting unit 21 sets the peak cut target value P _cut. In addition to the demand monitoring device cooperation control, the peak cut control according to the fourth embodiment can be performed. Then, the target power setting unit 21 sets the reverse power flow avoidance target value _PRPR to cooperate with the demand monitoring device. In addition to the control, the reverse power flow avoidance control according to the fifth embodiment can be performed.

In the ninth embodiment, the case where the storage battery B _k is used to suppress the electric power (maximum demand value) supplied from the electric power system A has been described, but the present invention is not limited to this. For example, various power generation devices may be used instead of the storage battery B _k . For example, a power generation device that uses natural gas, petroleum, LP gas, etc. as fuel to generate electricity by means of an engine, turbine, fuel cell, etc., or a power generation device that uses the heat generated when burning wood chips, burning garbage, etc. It may be. When such a power generation device is used, the centralized management device MC9 acquires the individual output power from each power generation device and calculates an index. Then, each power generation device controls the individual output power based on the index. As a result, when an alarm signal (contact signal) is emitted from the demand monitoring device 91, the power generation device starts power generation and supplies the generated power to the power load L. Therefore, the power supplied from the power system A can be suppressed, and the demand value (maximum demand value) can be suppressed. In this case, the power generation device corresponds to the "power supply device" of the present invention.

In the above-described ninth embodiment, as system interconnection system, a solar power generation system PVS9 comprising a solar cell SP _i and the power conditioner PCS _PVi has been described as an example, with a solar cell SP _i and the power conditioner PCS _PVi without a power load L, it may be provided with a storage battery B _k and the power conditioner PCS _Bk. In such a grid interconnection system, when the power consumption of the power load L increases, an alarm signal is transmitted from the demand monitoring device 91, so that the demand monitoring device cooperation control is performed. That is, it is possible to prevent the maximum demand value from increasing due to fluctuations in the power consumption of the power load L. Further, in the grid interconnection system (photovoltaic power generation system PVS9) including the power load L, the solar cell SP _i and the power conditioner PCS _PVi, and the storage battery B _k and the power conditioner PCS _Bk , the power load L In addition to the increase in power consumption, the demand monitoring device 91 also transmits an alarm signal when the amount of solar radiation decreases (when the amount of power generated by the solar cell SP _i decreases). Coordination control is performed. That is, it is possible to suppress an increase in the demand value (maximum demand value) due to not only the fluctuation of the power consumption of the power load L but also the fluctuation of the solar radiation.

In the first to ninth embodiments, the case where the grid interconnection system is a photovoltaic power generation system has been described as an example, but the present invention is not limited to this. The grid interconnection system may be another power generation system. Other power generation systems include, for example, a wind power generation system, a fuel cell power generation system, a rotary generator power generation system, and a virtual power generation system that manages the load of consumers by an aggregator that conducts negative watt trading. Conceivable. It should be noted that the aggregator considers the electricity saved by the negawatt transaction to be the generated electricity, so it does not actually generate electricity. Even in the case of these power generation systems, the centralized management device detects the interconnection point power or calculates the sum of the individual output powers to be the power to be adjusted, calculates the index, and transmits it to each power device. Then, the power device of each power generation system calculates the individual target power of its own device based on the optimization problem using the received index, and controls the individual output power so as to be the individual target power. In the case of a photovoltaic power generation system, a wind power generation system or a fuel cell power generation system, the power device is a power conditioner. Further, in the case of a power generation system using a rotary generator, the power device is a generator and a control device for controlling the generator. Further, in the case of a power generation system using an aggregator, the electric power device is a load of a consumer and a control device for controlling the load. In the power generation system using the aggregator, the saved power is regarded as the generated power, so the power reduced from the normal power consumption of the consumer's load becomes the individual output power. Further, the grid interconnection system may be a combination of the power generation system described above. For example, a rotary generator is added to the photovoltaic power generation system, and the centralized management device sends an index to each power conditioner of the photovoltaic power generation system and the controller of the generator to control the overall output. May be.

The electric power system according to the present disclosure is not limited to the above-described embodiment, and the specific configuration of each part can be freely redesigned as long as the contents described in the claims are not deviated.

PVS1~PVS9 photovoltaic system A power system SP _i solar cell B _k accumulator PCS _i, PCS _PVi, PCS _Bk power conditioner G _PV solar PCS group G _B battery PCS group 11, 11 ', 31, 31' receiving unit 12, 12', 12', 32, 32'Target power calculation unit 13,33 Output control unit 14,34 Output power detection unit 15,35 Transmission unit MC1 to MC9 Centralized management device 21 Target power setting unit 22 Interconnection point power Detection unit 23, 23', 23 "Indicator calculation unit 24, 24' Transmitter 25 Reception unit 61 Reception unit 62, 62', 62" Total output calculation unit 63, 63', 63 "Indicator calculation unit 91 Demand monitoring device 92 Contact signal receiver L Power load

Claims (5)

It is a grid interconnection system that is equipped with a power load, a plurality of power supply devices that supply power to the power load, and a centralized management device that manages the plurality of power supply devices, and is supplied with power from the power system. hand,
The centralized management device
An alarm signal receiving means for receiving an alarm signal transmitted from a demand monitoring device, and
A target power setting means for setting a target power for reducing the power supplied from the power system in response to the alarm signal, and
An index for controlling the individual output power of each of the plurality of power supply devices is calculated based on the total output power and the target power so that the total output power of the plurality of power supply devices becomes the target power. Index calculation means to be used
The index transmitting means for transmitting the index to each of the plurality of power supply devices is provided.
Each of the plurality of power supply devices
An index receiving means for receiving the index and
A target power calculation means for calculating an individual target power of each power supply device based on an optimization problem using the index, and a target power calculation means.
It is provided with a control means for controlling the individual output power of each power supply device so as to be the individual target power .
The alarm signal is transmitted from the demand monitoring device based on the adjusted power, which is the power that needs to be adjusted in order to make the demand value at the end of the current demand time period equal to or less than the preset target demand value.
The target power is a target value for limiting the demand value of the demand time period to the target demand value or less.
A grid interconnection system characterized by this. Each of the plurality of power supply devices is a storage battery power conditioner to which a storage battery is connected and supplies the power stored in the storage battery.
Each of the storage battery power conditioners
A detection means for detecting the individual output power of each storage battery power conditioner, and
It further includes an individual output power transmission means for transmitting the detected individual output power.
The centralized management device
Individual output power receiving means for receiving the individual output power transmitted from each storage battery power conditioner, and
As the total output power, a total output power calculation means for calculating the total of the individual output powers of each storage battery power conditioner is further provided.
The grid interconnection system according to claim 1 . The centralized management device
It further has a mode setting means for setting a charging mode for permitting charging of the storage battery.
The target power setting means sets a target power for charging the storage battery when the charging mode is set and the alarm signal is not received.
The grid interconnection system according to claim 2 . It also has a solar cell power conditioner with a solar cell connected to it.
The solar cell power conditioner supplies the electric power generated by the solar cell to the electric power load.
The grid interconnection system according to any one of claims 1 to 3 . The grid interconnection system according to any one of claims 1 to 4 ,
It has the demand monitoring device.
A power system characterized by that.