CN209844563U - Electric energy quality dynamic regulator for micro-grid - Google Patents
Electric energy quality dynamic regulator for micro-grid Download PDFInfo
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- CN209844563U CN209844563U CN201920979638.2U CN201920979638U CN209844563U CN 209844563 U CN209844563 U CN 209844563U CN 201920979638 U CN201920979638 U CN 201920979638U CN 209844563 U CN209844563 U CN 209844563U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/70—Wind energy
- Y02E10/76—Power conversion electric or electronic aspects
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
Abstract
The utility model relates to a microgrid power quality adjusts technical field, provides a power quality dynamic adjustment ware for microgrid, respectively with the microgrid, join in marriage net, load connection, the microgrid includes photovoltaic power generation system, wind power generation system, energy storage system, include: the system comprises a power quality monitoring module, a power quality dynamic controller and an inverter; the power quality monitoring module is used for detecting the power quality of a distribution network and a load; the power monitoring module is used for detecting active power and reactive power output by the microgrid. When the microgrid produced the electric energy quality problem, the utility model discloses an electric energy quality dynamic control ware synthesizes in the microgrid power supply side and the power balance condition of power consumption side, the control condition of dc-to-ac converter, energy storage system's running state, reachs electric energy quality dynamic adjustment instruction, adjusts each distributed power source's control strategy, and then reaches power balance and electric energy quality optimal in making the microgrid.
Description
Technical Field
The utility model relates to a microgrid power quality adjusts technical field, in particular to a power quality dynamic adjustment ware for microgrid.
Background
The microgrid is also called a microgrid, and refers to a small-sized power generation and distribution system composed of a distributed power supply, an energy storage device, an energy conversion device, a load, a monitoring and protection device and the like.
The microgrid is generally positioned at the tail end of a distribution network, and can form a power supply and utilization network which can be operated in a grid-connected mode and can be operated independently in an off-grid mode by distributed power supplies such as a photovoltaic power generation system and a wind power generation system. In the operation process of the microgrid, the quality of electric energy such as voltage, frequency, harmonic waves and the like of the microgrid can be influenced by the electric power supply side, such as the fluctuation of the voltage of a power grid; and may also be affected by the user side, such as various nonlinear loads and three-phase unbalanced loads incorporated into the microgrid by the user. Meanwhile, the output power of new energy power generation systems such as a photovoltaic power generation system and the like in the micro-grid can be influenced by factors such as weather and the like, and volatility and intermittence are presented. Power fluctuations in a microgrid may cause power imbalance between a power supply side and a power utilization side in the microgrid, particularly in an island microgrid, including imbalance of active power and imbalance of reactive power, which may cause fluctuations in voltage and frequency of the microgrid.
In summary, the power quality in the microgrid may be affected by the common effect of the power supply side and the user side, and may also be affected by the environmental factors of the distributed power sources of the microgrid itself, so that the power quality problem in the microgrid is complex and changes in real time along with the operating state of the microgrid. The optimal control effect is difficult to achieve by adopting the independent inverter for control, and the centralized monitoring and control are carried out by adopting the microgrid central controller, so that the system is more complex and the safety is reduced.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to improve the not enough that exists among the prior art, provide an electric energy quality dynamic adjustment ware for microgrid, make in the microgrid power supply side and power consumption side reach power balance and electric energy quality optimum.
In order to realize the purpose of the utility model, the embodiment of the utility model provides a following technical scheme:
the utility model provides an electric energy quality dynamic adjustment ware for microgrid, respectively with the microgrid, join in marriage net, load and the microgrid, join in net, load all insert the microgrid and exchange the generating line, the microgrid includes photovoltaic power generation system, wind power generation system, energy storage system, includes:
the power quality monitoring module is used for detecting the power quality of the distribution network and the load;
the power monitoring module is used for detecting active power and reactive power output by the microgrid;
the electric energy quality dynamic controller is respectively connected with the electric energy quality monitoring module and the power monitoring module and is used for adjusting the output voltage and the power of the microgrid;
the photovoltaic power generation system, the wind power generation system and the energy storage system are respectively connected with inverters, and the inverters are all connected with the electric energy quality dynamic controller.
Still further, in order to preferably implement the present invention, the mobile terminal further includes a peripheral auxiliary module, the peripheral auxiliary module includes:
the power supply circuit is respectively connected with the power quality monitoring module, the power monitoring module and the power quality dynamic controller;
the microgrid, the distribution network, the load, the inverter, the electric energy quality monitoring module, the power monitoring module and the electric energy quality dynamic controller are connected with a communication bus for communication.
Still further, in order to realize more optimally the utility model discloses, power quality monitoring module includes:
the first voltage sensor and the first current sensor are arranged at a common coupling point of the distribution network and the microgrid;
the second voltage sensor and the second current sensor are installed at the connecting point of the load merging microgrid alternating current bus;
the first voltage sensor, the first current sensor, the second voltage sensor and the second current sensor are all connected with the electric energy quality dynamic controller through communication buses.
Still further, in order to preferably implement the present invention, the power monitoring module includes:
the third voltage sensor and the third current sensor are arranged at the output port of the photovoltaic power generation system;
the fourth voltage sensor and the fourth current sensor are arranged at the output port of the wind power generation system;
the fifth voltage sensor and the fifth current sensor are arranged at the output port of the energy storage system;
and the third voltage sensor, the third current sensor, the fourth voltage sensor, the fourth current sensor, the fifth voltage sensor and the fifth current sensor are all connected with the electric energy quality dynamic controller through communication buses.
Furthermore, in order to realize the present invention more preferably, the power quality dynamic controller includes a microcontroller connected to the inverter and a peripheral circuit thereof, and the peripheral circuit includes a reset circuit, a clock circuit, and a memory.
Furthermore, in order to realize the utility model discloses more optimally, communication bus is RS 485.
Furthermore, in order to realize more optimally the utility model discloses, still include the microgrid central controller who is connected through communication bus and electric energy quality dynamic control platform.
Furthermore, in order to realize the utility model discloses more optimally, still include the touch-sensitive screen of being connected with electric energy quality dynamic control ware.
Compared with the prior art, the beneficial effects of the utility model are that:
the utility model discloses a two-way communication of each distributed power source in electric energy quality dynamic control ware and the microgrid, when the microgrid produced the electric energy quality problem, the power balance condition of side of supplying power and power consumption side in the electric energy quality dynamic control ware comprehensive microgrid, the control condition of distributed power source dc-to-ac converter, energy storage system's running state reachs electric energy quality dynamic adjustment instruction, adjust each distributed power source and energy storage system's control strategy, and then reach power balance and electric energy quality optimal in making the microgrid. The dynamic controller of the electric energy quality is arranged between the inverter of the microgrid and the central control system of the microgrid, the dynamic controller of the electric energy quality is in two-way communication with each inverter and load in the microgrid, and the dynamic controller of the electric energy quality is in one-way communication with the central control system of the microgrid, thus realizing dynamic adjustment of the electric energy quality and simultaneously ensuring the reliability and safety of the operation of the microgrid. Just the utility model discloses a device is simple reliable, the cost is low, can cooperate existing microgrid central control system to use, is applicable to the occasion that various electric energy quality adjusted in the microgrid.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
Fig. 1 is a block diagram of a module structure of the dynamic regulator for power quality according to the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiment of the present invention, all other embodiments obtained by the person skilled in the art without creative work belong to the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Also, in the description of the present invention, the terms "first," "second," and the like are used solely for distinguishing between the descriptions and not necessarily for indicating or implying any actual such relationship or order between such entities or operations.
Example 1:
the utility model discloses a following technical scheme realizes, as shown in fig. 1, an electric energy quality dynamic adjustment ware for microgrid, respectively with the microgrid, join in marriage net, load and be connected, and the microgrid, join in net, load and all insert the microgrid and exchange the generating line, the microgrid includes photovoltaic power generation system, wind power generation system, energy storage system, including electric energy quality monitoring module, power monitoring module, electric energy quality dynamic control ware, a plurality of dc-to-ac converter, electric energy quality monitoring module, power monitoring module are connected with electric energy quality dynamic control ware respectively, photovoltaic power generation system, wind power generation system, energy storage system are connected with one respectively the dc-to-ac converter, these dc-to-ac converters all are connected with electric energy quality dynamic control ware. The power quality monitoring module is used for detecting the power quality of a distribution network and a load; the power monitoring module is used for detecting active power and reactive power output by the microgrid; the electric energy quality dynamic controller is used for receiving the electric energy quality of the distribution network and the load detected by the electric energy quality monitoring module, and the electric energy quality of the microgrid and the output active power and reactive power detected by the power monitoring module, comprises the charge and discharge information of the energy storage system, and carries out calculation analysis on the electric energy quality and power conditions of the microgrid to generate corresponding instruction signals, and controls each inverter connected with the microgrid to adjust the voltage and power output by the microgrid, so that the cooperative work of the distributed power supply and the load is coordinated.
The dynamic power quality regulator also comprises a power circuit for respectively supplying power to the power quality monitoring module, the power monitoring module and the dynamic power quality controller, and a communication bus for connecting and communicating the microgrid, the distribution network, the load, the inverter, the power quality monitoring module, the power monitoring module and the dynamic power quality controller.
In the present embodiment, the photovoltaic power generation system, the wind power generation system, and the energy storage power generation system constitute a distributed power source on the power supply side, and the load is the power consumption side. The distributed power supply refers to a small and medium power supply system distributed around the power utilization side in the microgrid, and is not limited to a photovoltaic power generation system, a wind power generation system and an energy storage system.
Furthermore, the power quality monitoring module comprises a first voltage sensor, a first current sensor, a second voltage sensor and a second current sensor, wherein the first voltage sensor and the first current sensor are installed at a common coupling point of the distribution network and the microgrid and are used for detecting the power quality of the microgrid connected to the distribution network; the second voltage sensor and the second current sensor are arranged at a connecting point of a load merging microgrid alternating current bus and used for detecting the quality of electric energy at the position where the load is connected into the microgrid; and the first voltage sensor, the first current sensor, the second voltage sensor and the second current sensor are connected with the dynamic controller of the electric energy quality through communication buses, and the detected information of the electric energy quality is uploaded to the dynamic controller of the electric energy quality in real time.
The power monitoring module comprises a third voltage sensor, a third current sensor, a fourth voltage sensor, a fourth current sensor, a fifth voltage sensor and a fifth current sensor; the third voltage sensor and the third current sensor are arranged at the output port of the photovoltaic power generation system; the four voltage sensors and the fourth current sensor are arranged at the output port of the wind power generation system; the fifth voltage sensor and the fifth current sensor are arranged at the output port of the energy storage system; and the third voltage sensor, the third current sensor, the fourth voltage sensor, the fourth current sensor, the fifth voltage sensor and the fifth current sensor are all connected with the electric energy quality dynamic controller through communication buses.
The first to fifth voltage sensors and the first to fifth current sensors are all Hall sensors.
It should be noted that the distribution network is also called a distribution network, and is close to the power utilization side, and the general voltage level of the power system for distributing power energy to the power utilization side is lower. Usually, a microgrid with a low voltage level is connected with a power utilization side, so that the microgrid is connected to a certain node of a distribution network, a point where the microgrid is connected with the distribution network is called a common coupling point, and an alternating current switch is arranged at the common coupling point, in other words, the position of the alternating current switch is the common coupling point. When the alternating current switch is closed, the microgrid and the distribution network supply power for the load together, the working mode is called a grid-connected operation mode, and in the working mode, the voltage of the microgrid alternating current bus is clamped by the voltage of the distribution network, namely the voltage of the distribution network determines the voltage of the microgrid alternating current bus; if a fault occurs in the distribution network, the alternating current switch is disconnected, the photovoltaic power generation system, the wind power generation system and the energy storage system in the microgrid supply power for loads together, the working mode is called an off-grid running mode, in the working mode, the inverter connected with the energy storage system controls the voltage of the microgrid alternating current bus, and the power of the microgrid alternating current bus is balanced by controlling the electric energy sent by the energy storage system, so that the power between the power supply side and the power utilization side is balanced.
The quality of the electric energy is used for measuring quality indexes of the provided electric energy when a power grid (including a distribution network, a micro-grid and the like) supplies power to a load, and the indexes comprise three-phase voltage unbalance, voltage deviation, frequency deviation and harmonic wave.
The three-phase voltage balance refers to that three-phase alternating voltage in a power grid is standard three-phase sine wave when balanced, the phases are different from each other by 120 degrees, the amplitudes are the same, and if the conditions are not met, the three-phase voltage balance is called three-phase voltage unbalance. When the three-phase voltage is unbalanced, the three-phase voltage can be decomposed into a positive sequence component, a negative sequence component and a zero sequence component, and when the three-phase voltage is balanced, the three-phase voltage cannot be decomposed into the negative sequence component and the zero sequence component. Therefore, when the quality of the electric energy is detected, whether the three-phase voltage has a negative sequence component or not is detected, and whether the three-phase voltage is balanced or not can be judged.
Sum frequency of voltage deviationThe rate deviation refers to the deviation of the amplitude and frequency of the voltage supplied by the power grid from the amplitude and frequency ratings of the voltage. For example, a three-phase voltage of 380V has a voltage amplitude rating ofThe frequency rating is 50 Hz.
The harmonic wave refers to a standard sine wave form of voltage and current in a power grid if the voltage and the current are normal, if the sine wave form of the voltage or the current may be distorted under the influence of some factors, such as the influence of a load or an inverter in a microgrid, the fourier series is used for calculation and decomposition, the distorted sine wave form can be decomposed into components of multiple frequencies, for example, a 50Hz distorted sine wave can be respectively a 50Hz standard sine wave superimposed with a 150Hz standard sine wave, and a 250Hz standard sine wave is further superimposed, when such a set of standard sine waves is superimposed, the 50Hz standard sine wave is called a fundamental wave, and sine waves of other frequencies are called harmonic waves.
In this embodiment, the electric energy quality of the ac bus of the microgrid is affected by a plurality of aspects, including the influences of the distribution network, the photovoltaic power generation system, the wind power generation system, the energy storage system, and the load, that is, the influences of the distribution network side, the distributed power supply side, and the power consumption side, and there is also an interactive influence therebetween.
Furthermore, on the one hand, if the inverter connected to the energy storage system is not properly controlled, a power quality problem may occur; on the other hand, when the microgrid runs off-grid, the generated power of the photovoltaic power generation system and the wind power generation system is easy to convert and fluctuate, so that the power consumption power of the power consumption side fluctuates, and when the power of the power supply side and the power consumption side is unbalanced, the voltage amplitude and the frequency of the alternating current bus of the microgrid fluctuate and deviate.
Therefore, in the embodiment, the power quality monitoring module is adopted to monitor the power quality of the public coupling point of the microgrid and the distribution network and the power quality of the load connected to the alternating current bus of the microgrid, and the power quality is uploaded to the power quality dynamic controller through the communication bus to analyze and evaluate the degree of the power quality; the power monitoring module is adopted to monitor active power and reactive power of output ports of the photovoltaic power generation system, the wind power generation system and the energy storage system, the output ports are uploaded to the electric energy quality dynamic controller through a communication bus to be further calculated, and when the power is unbalanced, the adjustment is carried out, so that the influence on electricity consumption experience of an electricity consumption side is avoided.
The electric energy quality dynamic controller acquires data of signals transmitted by the communication bus, calculates and analyzes the data, obtains a specific control strategy according to calculation and analysis results of electric energy quality and power data, sends the control strategy to an inverter connected with a photovoltaic power generation system, an inverter connected with a wind power generation system and an inverter connected with an energy storage system which correspond to the microgrid, and dynamically adjusts the electric energy quality of the microgrid by adjusting parameters of the inverters so as to improve the electric energy quality; or the generated energy of the distributed power supply in the microgrid and the power consumption of the load are adjusted, so that the power balance between the power supply side and the power consumption side is realized.
It should be noted that the parameters of the inverter include parameters such as a power threshold, an electric energy quality index, and the like of the distributed power source corresponding to the inverter. The photovoltaic power generation system generates direct current, and the direct current is converted into alternating current to enter the micro-grid alternating current bus after passing through the inverter which is connected with the photovoltaic power generation system in a matched mode. The wind power generation system converts alternating current generated by the fan into direct current after rectification, and then the direct current is converted into alternating current through the inverter which is connected with the wind power generation system in a matching mode and enters the micro-grid alternating current bus. The storage battery in the energy storage system needs to be charged and discharged, external alternating current needs to be rectified and converted into direct current during charging, and direct current generated by the storage battery needs to be inverted into alternating current during discharging, so that the inverter connected with the energy storage system in a matching mode is a bidirectional converter. When the parameters of the inverter are adjusted, the instruction of the current or the output power output by the inverter can be set, so that the current and the power output by the distributed power supply are adjusted, namely the power generation amount of the distributed power supply is adjusted.
Still further, the power quality dynamic controller comprises a microcontroller connected with the inverter and peripheral circuits thereof, wherein the peripheral circuits comprise a reset circuit, a clock circuit, a memory and a plurality of comparator circuits. The comparator circuit is composed of an integrated operational amplifier, is respectively connected with the microcontroller, and is used for carrying out logic operation and arrangement on the detected current and voltage signals, and then uploading the signals to the electric energy quality dynamic controller. The electric energy quality dynamic controller is connected with a touch screen, and the touch screen is used for outputting parameters in the electric energy quality dynamic regulator and displaying the running state.
The electric energy quality dynamic controller is connected with a micro-grid central control system, and the micro-grid central control system is a system which is arranged in the micro-grid and used for monitoring and controlling the running state of the micro-grid. The system is generally composed of an upper computer and a corresponding system, and the monitoring of the microgrid generally refers to the generated energy of a photovoltaic power generation system and a wind power generation system, the state of an energy storage system, the connection state with a distribution network, the power utilization condition of a load and the like. When unbalance or power quality problems occur, a certain power supply side in the distributed power supply is directly selected to be cut off through the micro-grid central control system, or redundant electric quantity is directly unloaded and the like. Under the condition that sets up that does not change original microgrid central control system, use the utility model discloses can realize remedying the defect that microgrid central control system can not carry out the independent adjustment to the adjustment of electric energy quality and power, also can regard as the indirectness to upgrade microgrid central control system. More importantly, the utility model discloses a power quality dynamic control ware is unidirectional with microgrid central control system's communication connection direction, only allows power quality dynamic control ware to send information to microgrid central control system promptly, does not allow microgrid central control system to send information to power quality dynamic control ware, can guarantee whole power quality dynamic control ware's security like this.
It should be noted that, because the upper computer of the microgrid central control system is generally networked with the outside world to transmit data, if the microgrid central control system carefully controls each power generation device and power consumption unit in the microgrid, when the microgrid central control system is controlled by a virus, the breakdown of the microgrid power supply and power consumption system may be caused. Therefore, adopt the utility model provides an independent electric energy quality dynamic adjustment ware carries out careful control to the power supply side in the microgrid and with the electric side, and this regulator does not need the networking, and microgrid central control system only refers to the data that the regulator uploaded, nevertheless does not control it, can improve the security of microgrid.
To sum up, the utility model discloses a two-way communication of each distributed generator in electric energy quality dynamic control ware and the microgrid, when the microgrid produced the electric energy quality problem, the power balance condition of side of supplying power and power consumption side, the control condition of distributed generator dc-to-ac converter, energy storage system's running state in the electric energy quality dynamic control ware comprehensive microgrid reachs electric energy quality dynamic adjustment instruction, adjusts each distributed generator and energy storage system's control strategy, and then reaches power balance and electric energy quality optimal in making the microgrid. The dynamic controller of the electric energy quality is arranged between the inverter of the microgrid and the central control system of the microgrid, the dynamic controller of the electric energy quality is in two-way communication with each inverter and load in the microgrid, and the dynamic controller of the electric energy quality is in one-way communication with the central control system of the microgrid, thus realizing the dynamic adjustment of the electric energy quality and simultaneously ensuring the reliability and the safety of the regulator. Just the utility model discloses a device is simple reliable, the cost is low, can cooperate existing microgrid central control system to use, is applicable to the occasion that various electric energy quality adjusted in the microgrid.
Example 2:
the embodiment is further optimized on the basis of the embodiment 1, as shown in fig. 1, the power quality dynamic controller monitors the power generation power of each distributed power source and the power consumption power of the load in the microgrid in real time, when the power generation power of each distributed power source is higher than the power consumption power of the load, the power quality dynamic controller judges the depth of discharge of the energy storage system through voltage and current signals of the energy storage system, and when the depth of discharge of the energy storage system is higher than a preset first threshold, the power quality dynamic controller sends out a command for charging the energy storage system, and at this time, the energy storage system is controlled to be in a charging state; if the energy storage system is charged completely or the depth of discharge of the energy storage system is lower than a first threshold value, monitoring the state of a temperature regulation load in the microgrid, and controlling the temperature regulation load to operate to absorb the redundant power generation power of the distributed power supply when the temperature regulation load can work; and if the temperature regulation load works in the optimal state, the redundant energy of the distributed power supply is merged into the distribution network, or part of the distributed power supply is cut off.
When the power generation power of the distributed power supply is lower than the power consumption power of the load and the microgrid is in an off-grid operation mode, the microgrid of the electric energy quality dynamic controller sends a discharge instruction and a power reference value to control the energy storage system to operate in a complementary mode with the microgrid, and the power supply to the load is maintained.
Through the control, the power of the power supply side and the power utilization side of the microgrid can be stabilized in a balanced state, the voltage and the frequency of the microgrid cannot fluctuate greatly, and the adjustment of the electric energy quality is preliminarily realized through the power balance control of the distributed power supply and the load.
The depth of discharge of the energy storage system refers to the degree of discharge of the stored electric quantity of the storage battery in the energy storage system, and the depth of discharge is related to the service life of the storage battery, so the depth of discharge of the storage battery is monitored and controlled. In the depth of discharge detection, the state of charge of the battery is usually detected, or the port voltage of the battery is monitored, and the port voltage has a positive linear relationship with the depth of discharge. The preset first threshold of the depth of discharge is a value that the storage battery is insufficient in stored electric quantity and needs to be charged, and is equivalent to a port voltage value of the storage battery.
When the micro-grid runs, the comprehensive evaluation result of the micro-grid electric energy quality can be obtained after data acquisition, calculation and analysis are carried out on voltage and current signals of a public coupling point of the micro-grid and a distribution network of the electric energy quality dynamic controller and a load at a micro-grid alternating current bus. When the electric energy quality evaluation result of the microgrid exceeds an electric energy quality index, firstly, the active power balance state and the reactive power balance state of the power supply side and the power utilization side in the microgrid are evaluated, whether the power generation power of the distributed power supply is higher than or lower than the power utilization power of the load is judged, and then the power balance is controlled by using the above mode. Meanwhile, the power quality dynamic controller generates a control strategy of each inverter according to the severity of each index in the power quality of the microgrid.
For example, when the microgrid is in an off-grid operation mode and the three-phase voltage of the alternating-current bus of the microgrid is unbalanced seriously, the dynamic controller of the electric energy quality sends an instruction and a negative sequence voltage reference value to an inverter which is used for stably controlling the voltage in the microgrid, so that the inverter adjusts the control structure and adds a negative sequence voltage control link, namely, the three-phase voltage balance of the alternating-current bus of the microgrid is maintained through the control of the negative sequence voltage. Similarly, when the voltage amplitude or the frequency of the microgrid alternating-current bus in the off-grid operation mode deviates from a rated value, the power quality dynamic controller sends a control instruction to enable the inverter to adjust the control strategy, so that the voltage and the frequency of the microgrid alternating-current bus are maintained at the rated value.
When the microgrid is in a grid-connected operation mode and the three-phase voltage of the AC bus of the microgrid is unbalanced due to the fact that a large number of loads with unbalanced three-phase voltages are incorporated into the microgrid, the dynamic electric energy quality controller monitors the negative sequence component in the load current and obtains a negative sequence current value to be compensated for once, and the negative sequence current value to be compensated is distributed to each distributed power source and the energy storage system according to the capacity proportion of each distributed power source and the energy storage system in the microgrid, namely, each distributed power source and the energy storage system are controlled to send out negative sequence compensation current, and the three-phase voltage balance of the AC bus of the microgrid is recovered.
When the microgrid is ready to be switched to a grid-connected operation mode from an off-grid operation mode, in order to ensure the instantaneous electric energy quality of the state switching of the microgrid, an electric energy quality dynamic controller detects information such as voltage amplitude, phase and the like of a power supply side and takes the information as a reference value to be sent to an inverter in the microgrid, the voltage of an output port of the inverter is controlled to be gradually adjusted, the voltage gradually approaches the voltage of a distribution network according to the alternating current bus of the microgrid, when the voltage of the microgrid is completely synchronous with the voltage of the distribution network, the electric energy quality dynamic controller sends a closed instruction signal to an alternating current switch at a public coupling point of the microgrid and the distribution network to close the alternating current switch, so that the microgrid is successfully switched to the grid-connected operation mode from the off-grid operation mode, the impact of instantaneous voltage and.
When the dynamic controller for the electric energy quality dynamically adjusts the electric energy quality of the microgrid, monitored data and running instructions are also uploaded to the central control system of the microgrid through the communication bus, but the communication is one-way communication at the moment, so that the reliability and the safety of the regulator are ensured, and the complexity of the system is reduced.
Other parts of the embodiment are the same as those of the above embodiment, and thus are not described again.
The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. The utility model provides an electric energy quality dynamic adjustment ware for microgrid, respectively with the microgrid, join in marriage net, load and be connected, and the microgrid, join in net, load and all insert the microgrid and exchange the generating line, the microgrid includes photovoltaic power generation system, wind power generation system, energy storage system, its characterized in that: the method comprises the following steps:
the power quality monitoring module is used for detecting the power quality of the distribution network and the load;
the power monitoring module is used for detecting active power and reactive power output by the microgrid;
the electric energy quality dynamic controller is respectively connected with the electric energy quality monitoring module and the power monitoring module and is used for adjusting the output voltage and the power of the microgrid;
the photovoltaic power generation system, the wind power generation system and the energy storage system are respectively connected with inverters, and the inverters are all connected with the electric energy quality dynamic controller.
2. The dynamic power quality regulator for microgrid according to claim 1, characterized in that: further comprising a peripheral assist module, the peripheral assist module comprising:
the power supply circuit is respectively connected with the power quality monitoring module, the power monitoring module and the power quality dynamic controller;
the microgrid, the distribution network, the load, the inverter, the electric energy quality monitoring module, the power monitoring module and the electric energy quality dynamic controller are connected with a communication bus for communication.
3. The dynamic power quality regulator for microgrid according to claim 2, characterized in that: the power quality monitoring module comprises:
the first voltage sensor and the first current sensor are arranged at a common coupling point of the distribution network and the microgrid;
the second voltage sensor and the second current sensor are installed at the connecting point of the load merging microgrid alternating current bus;
the first voltage sensor, the first current sensor, the second voltage sensor and the second current sensor are all connected with the electric energy quality dynamic controller through communication buses.
4. The dynamic power quality regulator for microgrid according to claim 2, characterized in that: the power monitoring module includes:
the third voltage sensor and the third current sensor are arranged at the output port of the photovoltaic power generation system;
the fourth voltage sensor and the fourth current sensor are arranged at the output port of the wind power generation system;
the fifth voltage sensor and the fifth current sensor are arranged at the output port of the energy storage system;
and the third voltage sensor, the third current sensor, the fourth voltage sensor, the fourth current sensor, the fifth voltage sensor and the fifth current sensor are all connected with the electric energy quality dynamic controller through communication buses.
5. The dynamic power quality regulator for microgrid according to claim 1, characterized in that: the power quality dynamic controller comprises a microcontroller and a peripheral circuit thereof, wherein the microcontroller is connected with the inverter, and the peripheral circuit comprises a reset circuit, a clock circuit and a memory.
6. The dynamic power quality regulator for microgrid according to claim 2, characterized in that: the communication bus is RS 485.
7. The dynamic power quality regulator for microgrid according to claim 2, characterized in that: the micro-grid central controller is connected with the power quality dynamic control platform through a communication bus.
8. The dynamic regulator of electric energy quality for microgrid according to any one of claims 1 to 7, characterized in that: the system also comprises a touch screen connected with the dynamic controller of the power quality.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111541305A (en) * | 2020-05-01 | 2020-08-14 | 河南龙翔电力研究院股份有限公司 | Micro-grid platform based on data detection system |
| CN112510737A (en) * | 2020-11-25 | 2021-03-16 | 国网湖南省电力有限公司 | Grid-connected and off-grid cooperative control method and system for photovoltaic energy storage charging station |
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2019
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111541305A (en) * | 2020-05-01 | 2020-08-14 | 河南龙翔电力研究院股份有限公司 | Micro-grid platform based on data detection system |
| CN112510737A (en) * | 2020-11-25 | 2021-03-16 | 国网湖南省电力有限公司 | Grid-connected and off-grid cooperative control method and system for photovoltaic energy storage charging station |
| CN112510737B (en) * | 2020-11-25 | 2023-05-23 | 国网湖南省电力有限公司 | Photovoltaic energy storage charging station grid-connected and off-grid cooperative control method and system |
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