JPH09135536A - Power system interconnection system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the relation between the amount of output power and the amount of consumed power of an AC power source by allowing a second information transmission means to receive the information about the power used by a plurality of power consumers and the amount of power generation of distributed power supplies from a third information transmission means and transmit that information to a first information transmission means. SOLUTION: A first information transmission means 1 is located uppermost in the load-dispatch instruction transmission system and sends an instruction for adjusting the supply and demand balance to a second and a third information transmission means 2, 3. The second information transmission means 2, being located in a transformer station 11 for power distribution, monitors the amount of power generation, the amount of power consumption, etc., of a distributed power supply in each group based on the instruction received from the first information transmission means 1 and then outputs to the third information transmission means 3 the appropriate information and control signals which are obtained from the instruction of the first information transmission means 1 and the relation among the amount of power generation, the amount of power consumption, etc., of each distributed power supply. By this method, the relation between the amount of power generation and the amount of power consumption of the power system can be optimized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises an electric power system having an AC power source composed of power generation means such as thermal power generation, and a power generation means such as photovoltaic power generation provided in a consumer or the like and connected to the electric power system. The present invention relates to a system interconnection system that is composed of distributed power sources and is suitable for controlling the distributed power sources according to the situation such as the amount of power generation of the AC power source to control the power flow to equalize the power generation capacity of the AC power source.

[0002]

2. Description of the Related Art In recent years, power sources using solar power generation, fuel cell power generation, etc. have been developed.

However, the output of solar power generation is easily affected by the weather, and it is difficult to generate power at night. Further, in the fuel cell power generation, since there is a suspension period for inspection, there is a problem in that it is impossible to supply a stable power to the customer if these power sources are used alone. Therefore, conventionally, a stable supply of electric power is performed by connecting the above-mentioned power generation means to a power system having an AC power source as a distributed power source for use.

In this case, the orthogonal conversion means for converting the DC voltage output from the photovoltaic power generation into the AC voltage for interconnection, and the protection device, switch and switch necessary for interconnection with the electric power system,
Electric power is supplied by an interconnection means such as a filter, which is connected to the electric power system. A similar system is described in, for example, Japanese Patent Laid-Open No. 6-14461.

[0005]

Up to now, the reverse flow from the distributed power source to the electric power system has not been possible due to regulations. However, from now on, when the power system and the distributed power source are interconnected in a normal state, the surplus power of the distributed power source can be reversely flowed to the power system and sold to the power company.

However, in the conventional system interconnection system, this reverse power flow is not taken into consideration, and when the number of distributed power sources connected to the power system increases, the power fluctuation given to the power system by the distributed power sources increases. In particular, in the case of a distributed power source using solar power generation, its output depends on the weather, so that the power fluctuation given to the power system becomes very large, which is a big problem for the power system. Therefore, it is important to control the distributed power sources connected to the power system to avoid such a problem and to level the power generation capacity of the AC power source.

An object of the present invention is to supply a stable electric power to a customer while being able to reversely flow a stable electric power corresponding to the amount of electric power generated by the electric power generating means to an electric power system of an AC power source having an electric power generating means. Another object of the present invention is to provide a system interconnection system capable of achieving the above, and optimizing the relationship between the power generation amount of the AC power supply and the power consumption amount.

[0008]

To achieve the above object, the present invention is characterized in that an electric power system having an AC power source equipped with a power generation unit and a plurality of electric power consumers each having a distributed power source. In a system interconnection system interconnected by a system interconnection means, first information transmission means for generating information about power generation of the AC power source, and information about the power generation from the first information transmission means are received. Second information transmission means for generating a control signal for controlling the power flow of the distributed power sources of the plurality of electric power consumers according to
Generating information about the power used by the plurality of power consumers and the power generation amount of the distributed power source and sending the information to the second information transmitting means;
A third information transmission means for receiving a control signal for performing the power flow control from the second information transmission means, and performing a power flow control of the distributed power source and a load factor control of a load group according to the control signal, The second information transmission means receives from the third information transmission means information regarding the electric power used by the plurality of electric power consumers and the power generation amount of the distributed power source, and sends the information to the first information transmission means. System.

[0009]

FIG. 1 shows an embodiment of the present invention.

In FIG. 1, 1 is a first information transmission means,
2 is a second information transmission means, 3 is a third information transmission means, 1
Reference numeral 0 is an AC power source including power generation means such as thermal power generation, 11 is a distribution substation, 12 is a circuit breaker, and 13 is a pole transformer.

The power generated by the AC power source 10 is distributed to the substation 1 for distribution.
The voltage is stepped down to 6.6 kV by 1 and is branched from the distribution substation 11 by the distribution system 14 and distributed to each group of group 1, group 2, ..., Group n. The branch power of each distribution system 14 is supplied to the pole transformer 13 provided in each group via the circuit breaker 12 and the distribution system 15. The power supplied to the pole transformer 13 has a voltage of 200 V or 10 at the pole transformer 13.
It is stepped down to 0V and supplied to the customers 20 and the like.

Numeral 21 is a solar cell installed in each of the customers A20 and B20 as a distributed power source, 22 is an orthogonal converter for converting the DC voltage output from the solar cell 21 into an AC voltage, and 30 is an AC voltage. It is a load group such as air conditioners, lights, and refrigerators that operate. When the electric power supplied from the solar cell 21 to the load group 30 is not sufficient, the reference numeral 23 makes it possible to supply the electric power from the electric power system to the load group 30, and a protection device 24 for detecting an electric power system abnormality, an electric power system abnormality. Switch 25 for disconnecting the dispersed power source of the solar cell 21 at times
It is a system interconnection device configured by.

Further, in addition to the distributed power source including the solar cells 21 installed in the customers A and B, the storage battery 40 having a power storage function is used as a distributed power source, and the DC voltage output from the storage battery 40 is converted into an AC voltage. An orthogonal converter 41 for conversion and a system interconnection device 42 which is an interconnection means for connecting the distributed power source and the electric power system are installed. Here, as surrounded by the alternate long and short dash line in FIG. 1, each customer 20 connected to the distribution system 16 from the pole transformer 13 is configured as one group.

In FIG. 1, the first information transmission means 1 is located at the top of the power supply command and outputs a demand / supply adjustment command to the second information transmission means 2 and the third information transmission means 3. The lower second information transmission means 2 is located in the distribution substation 11, and monitors the power generation amount, the power consumption amount, etc. of the distributed power sources of each group based on the command from the first information transmission means 1, Command from the information transmission means 1 of No. 1 and the power generation amount of the distributed power source
It is executed so as to output appropriate information and control signals to the third information transmission means 3 in relation to the power consumption and the like. The third information transmitting means 3 is in charge of driving operation commands for the customers 20 and the like connected to the power distribution system 16 which is a jurisdiction power system, and is provided according to the power distribution system 16 by a plurality, that is, by the number of groups. And directly exchanges control signals with the control device 26 of the customer 20.

An embodiment of the present invention shown in FIG. 1 will be described with reference to FIGS. 2, 3 and 4. FIG. 2 shows the relationship among the first information transmitting means 1, the second information transmitting means 2 and the third information transmitting means 3. FIG. 3 is a diagram for explaining the operation of the customer 20 according to the detailed configuration of the customer 20 in the embodiment of FIG. 1 of the present invention, the information of the third information transmission means and the control device 26, and the control signal. FIG. 4 is a drawing showing the flow of processing executed in accordance with information and control signals.

As shown in FIG. 1 and FIG. 3, the third information transmission means 3 has the information from the first information transmission means 1 and the second information transmission means 2, which are superior to the control device 26 of the customer 20. Information and control signals are exchanged such that a command corresponding to the control signal is output to the control device 26, and information and control signals from the control device 26 are output to upper first and second information transmitting means. As shown in FIG. 1, an information network is constructed from the first information transmission means 1 to the control device 26 so as to control the power generation amount of the distributed power source, control the power flow, apply the load, and disconnect.

For example, when the amount of power generated by the AC power source 10 is insufficient, such as during peak summer power consumption, or when the amount of power generated is small, or conversely, the amount of power generated by the AC power source 10 is consumed by each consumer. It is larger than the quantity and may be left over. Such phenomena occur depending on the season or the time of day,
It is difficult to control the amount of power generation according to the amount of power consumption that changes moment by moment. Also, large load fluctuations in the power system are not preferable in order to level the amount of generated power. Therefore, the first information transmission unit 1, the second information transmission unit 2, and the third information transmission unit 3 are used to map the information such as the power generation amount and the power consumption amount of the distributed power sources in the group shown in FIG. According to the processing flow shown in FIG. 4, the control signal is transmitted / received, and the power generation amount of the distributed power source of the customers 20 in the group,
The power flow control and the load factor of the load group 30 are controlled. Hereinafter, FIG.
A specific operation will be described using.

In process 500, the amount of power generated by the AC power source 10 is calculated, and the amount of generated power and the power distribution system 14 after the distribution substation 11 that is sent from the second information transmission means 2 to the first information transmission means 1. Power consumption in step 501,
If the generated power amount is large, the process of step 502 is executed, and if the generated power amount is small, the process of step 507 is executed.

In process 502, it is determined whether or not the preset power generation amount has been exceeded according to the season or time, and if it exceeds, the first information transmission is performed in process 503 so as to suppress the power generation amount. A command is output to the means 1 to suppress the amount of power generated by the AC power supply 10. If the set power generation amount is not exceeded, the power generation amount of the distributed power source of the customer 20 and the power consumption amount in the load group 30 sent from the third information transmitting unit 3 to the second information transmitting unit 2 From the information, the amount of power purchased by the power system from each customer 20 in the group is calculated in process 504, and it is determined in process 505 whether the amount of power purchased is greater than the contract value, and the amount of power purchased is less than the contract value. When it is small, the set power generation amount is suppressed by the process 503. When the power purchase amount is larger than the contract value, a command from the second information transmission means 2 is output to the control device 26 via the third transmission means 3,
As shown in process 506, the power generation amount of the distributed power source with a large power sale amount is controlled or disconnected by the customers in the group whose power purchase amount is larger than the contract value, and power flow control is performed. By executing such a processing flow, it becomes possible to optimize the power generation amount and the power consumption amount of the power system.

Here, a specific method of disconnecting the distributed power sources and controlling the power flow will be described later. For example, as shown in FIG. 3, the protection device 24 of the grid interconnection device 23 is replaced by the control device 26.
It is possible to realize it by controlling with the switch and opening the switch 25. Further, the power generation amount of the distributed power source can be realized by controlling the orthogonal transformer 22 according to a command from the control device 26.

On the other hand, if the amount of power consumption is large and the amount of power generated by the AC power source 10 is insufficient, then step 507 is executed.
That is, the amount of power set in advance for each group is compared with the amount of power consumption of the group, and for a group with a large amount of power consumption, the amount of power shortage is calculated in step 510, and the load is taken in step 511 according to the magnitude. Of the load is determined, and if it is possible, a command to disconnect the load is output to the third information transmission means 3, and the load group 30 is required by the control signal from the control device 26 according to the priority order. The load of the load group 30 is disconnected and the load factor is controlled until the amount of electric power becomes appropriate. Load group 30
The loads 1, ..., N of the load train are prioritized in advance and the switches 32, 33, and 34 are opened by a control signal from the control device 26 as shown in FIG. Low loads can be released in sequence. However, depending on the situation, if the load group 30 cannot be disconnected, or if the power is insufficient even if the load at the limit that can be disconnected is insufficient, the controller 2 is requested to supply power as shown in process 513.
6 to the third information transmission means 3. On the other hand, in the case of the group in which the power consumption amount in the group is small and the power is surplus in the process 507, the surplus power amount is calculated in the process 508, and the surplus power is reversely flowed to the power system in the process 509 to purchase the power. . Also, this surplus power can be supplied to the group requesting the power. As a result, it becomes possible to optimize the amount of power generated and the amount of power consumed in the power system by adjusting the supply and demand of electric power between the groups. Here, power purchase means that the power company purchases power.

According to the present embodiment described above, the control unit 26 controls the power generation amount and power flow of the distributed power sources in each group connected to the AC power source 10, and the load factor of the load group 30 to control the power of the grid. It is possible to suppress fluctuations and to flow stable power corresponding to the amount of power generated by the power generation means in the reverse direction to the power system, and to supply stable power to consumers.
Furthermore, it becomes possible to adjust the supply and demand of electric power between the groups, and it is possible to supply stable electric power to customers. Therefore, AC power supply 1
Since the relationship with the amount of power consumed by the distribution system 14 can be optimized according to the amount of generated power of 0, there is an effect that the amount of generated power of the AC power supply 10 can be leveled.

Another embodiment of the present invention will be described with reference to FIGS. 5, 6 and 7.

In the present embodiment, the processing 509 shown in FIG. 4 is changed according to the situation of the customers in the group. For example, group 1 has a small amount of power consumption and surplus power, and can flow backward to the power system. On the other hand, the group 2 is processed by the process 513 from the control device 26 to the third information control means 3
Suppose you are requesting a power supply to. In this case, the process is changed as shown in FIG. 5 depending on whether or not the power system needs the surplus power from the customer 20.

That is, when the power system needs the surplus power of the group 1, the reverse flow is directly performed to the power system as shown in process 515. On the other hand, if the power system does not need it or does not need it anymore, the process 5
In 16 it is determined whether there is a power-deficient customer in the group, and if there is a customer consuming a large amount of power and having a shortage of power, as indicated by the solid line in FIG. Supply the surplus electricity to the shortage customers. That is, as shown in FIG. 6, for example, when the customer A has a power shortage and the customer B has surplus power, the surplus portion is a loop shown by a solid arrow, and the customer B has a power shortage and the customer A has a surplus power. If there is, the surplus power is supplied by a loop indicated by a two-dot chain line arrow, and the power is exchanged between the customers in the group. In addition, when there is no customer who lacks power, or when surplus power is supplied and there is still power, reverse power flow is performed in the power system and that power is provided in the same group as shown by the solid line in FIG. It is supplied to a common storage battery 40 having a power storage function and stored. Therefore, when the power supply from the power system is insufficient, the DC power of the storage battery 40 is converted into AC by the orthogonal converter 41 as indicated by the chain double-dashed line, and the consumers 20 in the group are connected via the grid interconnection device 42. Supply to. In this way, by adjusting the power supply and demand between the customers in the group and the storage battery 40 having the power storage function, it becomes possible to optimize the generated power amount and power consumption amount of the power system.

According to another embodiment of the present invention described above, the controller 26 controls the power generation amount of the distributed power sources in each group connected to the AC power source 10, the power flow control, and the load factor of the load group 30. As a result, it is possible to suppress power fluctuations in the grid and to supply a stable power corresponding to the amount of power generated by the power generation means to the power grid in the reverse direction, and to supply a stable power to the customer. In addition, surplus power can be exchanged between customers in each group connected to the AC power supply 10, and power can be supplied from the storage battery 40 that stores surplus power when power is insufficient. It becomes possible to adjust the power supply and demand by exchanging electric power within the group. Therefore, in order to control the power supply from the power grid,
Since the power consumption amount can be optimized according to the power generation amount of the AC power source 10, there is an effect that the power generation amount of the AC power source 10 can be leveled.

FIG. 8 shows a concrete method for realizing the power flow control of the distributed power source.

In FIG. 8, a signal logic circuit 27 is provided for inputting a control signal from the third information transmitting means 3 and a control signal from the control device 26, logically multiplying these control signals and outputting the control signal. There is. That is, the signal logic circuit 27
Takes in the control signal from the third information transmission means 3 and the signal encoding the operating condition of the distributed power source or the power generation amount from the control device 26, and obtains the logical product of both signals to obtain the condition By opening and closing the switch 25 of the grid interconnection device 23 by the control signal output when they match, the power flow control of the distributed power source can be performed.

As shown in FIG. 3, the control signal from the third information transmitting means 3 is directly taken into the consumer's control unit 26, and the control signal and the operating condition of the distributed power source or the amount of power generation are set in the control unit 26. A control signal corresponding to the situation is output from the control device 26 to the grid interconnection device 23 by taking a logical product with a signal obtained by encoding
By opening and closing the switch 25, the power flow of the distributed power source can be controlled. Further, although control of the power generation amount of the distributed power source is omitted in the figure, the output of the orthogonal transformer 22 is detected,
This is possible by controlling the output with the control device 26.

Further, by operating the quadrature converter 22 shown in FIG. 3 with, for example, an active filter function and a reactive power compensation function, it is possible to prevent harmonic outflow to the power system and improve the stability of the power system. . Therefore, it is possible to open / close the distributed power sources according to the command from the power system to control the power flow, and to control the power generation amount of the distributed power sources, and the power fluctuations when the distributed power sources are connected to or disconnected from the power system. And deterioration of power quality can be prevented.

[0031]

According to the present invention, according to the control signal from the upper information transmission means for monitoring the power generation amount of the AC power source, the power generation amount of the distributed power source connected to the AC power source, the power flow control, and the load group. By controlling the load factor by the control device of the customers in each group, it is possible to suppress fluctuations in the power of the grid and to flow a stable amount of power in the reverse direction to the grid, corresponding to the amount of power generated by the power generation means. Can be adjusted, and stable power can be supplied to customers. Therefore,
The relationship with the amount of power consumed by the distribution system can be optimized according to the amount of power generated by the AC power supply, and there is the effect that the power generated by the AC power supply can be leveled.

Furthermore, by controlling the load factor of the power generation amount, the power flow control and the load group of the distributed power sources in each group connected to the AC power source by the control device, the demand in each group connected to the AC power source. Excessive power can be shared between households, and it is possible to store excess power in a storage battery that has a power storage function, so that when a customer lacks power, power is supplied from the storage battery that stores excess power. You can In this way, it becomes possible to adjust the supply and demand of electric power within the group, and it becomes possible to accommodate electric power within the group. Therefore, the power supply from the power system can be controlled, and the power consumption amount can be optimized according to the power generation amount of the AC power supply, so that the power generation of the AC power supply can be leveled.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation of the embodiment in FIG.

FIG. 3 is a diagram for explaining the operation of the embodiment in FIG.

FIG. 4 is a drawing for explaining the operation of the embodiment in FIG.

FIG. 5 is a diagram for explaining the operation of another embodiment of the present invention.

FIG. 6 is a diagram illustrating the operation of another embodiment of the present invention.

FIG. 7 is a diagram for explaining the operation of another embodiment of the present invention.

FIG. 8 is a drawing for explaining the operation of the embodiment of the present invention.

[Explanation of symbols]

1 ... 1st information transmission means, 2 ... 2nd information transmission means, 3
... Third information transmission means, 10 ... AC power supply, 11 ... Distribution substation, 12 ... Breaker, 13 ... Pole transformer, 14,1
5, 16 ... power distribution system, 20 ... consumer, 21 ... solar cell,
22, 41 ... Orthogonal transformer, 23, 42 ... System interconnection device,
24 ... Protective device, 25 ... Switch, 26 ... Control device, 27
... Signal logic circuit, 30 ... Load group, 31, 32, 33, 3
4 ... Switch, 35 ... Distribution board.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuaki Suzuki 7-1-1, Omika-cho, Hitachi-shi, Ibaraki Hitachi Ltd. Hitachi Research Laboratory (72) Inventor Hideyasu Umezu 3-chome, Saiwai-cho, Hitachi, Ibaraki No. 1 Stock company Hitachi Ltd. Hitachi factory (72) Inventor Tsutomu Inayama 3-2-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Engineering Co., Ltd.

Claims (5)

[Claims] 1. A system interconnection system in which an electric power system having an AC power source having a power generation unit and a plurality of electric power consumers each having a distributed power source are interconnected by a system interconnection unit, the power generation of the AC power source. And a control signal for receiving the information about the power generation from the first information transmission means and controlling the power flow of the distributed power sources of the plurality of power consumers according to the information. A second information transmitting means for generating, and generating and transmitting to the second information transmitting means information relating to the electric power used by the plurality of electric power consumers and the power generation amount of the distributed power source.
A third information transmission means for receiving a control signal for performing the power flow control from the second information transmission means, and performing a power flow control of the distributed power source and a load factor control of a load group according to the control signal, The second information transmitting means may receive information on the electric power used by the plurality of electric power consumers and the power generation amount of the distributed power source from the third information transmitting means, and may send the information to the first information transmitting means. A characteristic grid interconnection system. 2. The system interconnection system according to claim 1, wherein the distributed power source includes a power generation unit having a power storage function and a power generation unit such as a solar cell or a fuel cell. 3. The information transmission means according to claim 1, wherein the first information transmission means is the AC power source, the second information transmission means is a distribution substation facility, and the first information transmission means is for each of the plurality of electric power consumers. A system interconnection system characterized in that it is provided corresponding to each transformer provided. 4. In claim 1, when the electric power of the AC power supply is insufficient, the loads of the plurality of electric power consumers are disconnected, or the surplus electric power of the plurality of electric power consumers is reversed to the electric power system. A system interconnection system characterized by controlling the power flow of the distributed power sources so as to allow the power flow. 5. The opening / closing means of the distributed power source for realizing the power flow control of the distributed power source according to the power generation amount of the AC power source according to claim 1, wherein the control signal from the third information transmission means and the distributed power source A system interconnection system characterized by being opened and closed by a signal obtained by taking a logical product with a control signal from a control device.