A grid-connected point voltage active support strategy and system coordinated with energy storage and master control

Abstract

The application discloses a kind of energy storage and wind power master control coordinated grid-connected point voltage active support strategy and system, real-time monitoring grid-connected point voltage by power scheduling system, and according to the different implementation of different control strategies of grid-connected point voltage, the power compensation value needed by energy storage and wind farm combined system is calculated, and it is distributed to wind farm and energy storage.AC-DC hybrid power grid system includes AC power grid and HVDC receiving end;By the application, different voltage control strategies can be used according to the real-time observation value of grid-connected point voltage, and the output capacity of the combined system is fully utilized to provide corresponding power compensation for the grid-connected point, maintain the stability of the grid-connected point voltage, improve the power factor, solve the problem that the existing technology does not consider effectively improving the power factor of the grid-connected point, and implement different control strategies according to whether the grid-connected point voltage is out of limit, thereby adjusting the grid-connected point voltage.

Description

Technical Field

[0001] This invention relates to the field of voltage regulation technology, and in particular to an active voltage support strategy and system for grid connection point that coordinates energy storage and main control. Background Technology

[0002] The integration of clean energy into the power grid has a significant impact on the safe and stable operation of the grid, often causing voltage fluctuations or even exceeding limits at the grid connection point. Therefore, grid-connected clean energy power plants are required to have high-precision voltage regulation capabilities.

[0003] Chinese patent CN112803429A discloses a method for coordinated voltage control of energy storage and wind turbine units, which fully utilizes the reactive power regulation capabilities of energy storage and clean energy power plants and provides reactive power deficit to the grid connection point through a reasonable reactive power allocation strategy, thereby maintaining the stability of the grid connection point voltage. However, the above patent has the following problems: This type of solution does not take into account the issue of effectively improving the power factor at the grid connection point, nor the issue of implementing different control strategies based on whether the grid connection point voltage exceeds the limit, thereby adjusting the grid connection point voltage in a targeted manner. Therefore, it is necessary to design an active grid connection point voltage support strategy and system that coordinates energy storage and main control to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a strategy and system for actively supporting grid connection point voltage in coordination of energy storage and main control. This solution solves the problem that existing technologies cannot implement different control strategies based on whether the grid connection point voltage exceeds the limit. It has the characteristics of being able to make full use of the output capacity of the combined system to provide corresponding power compensation for the grid connection point, maintain the stability of the grid connection point voltage, and improve the power factor.

[0005] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A grid connection point voltage active support strategy that coordinates energy storage and main control includes the following steps: S1, the power dispatch system detects the voltage and current of the grid connection point PCC of the wind farm and energy storage, as well as the voltage and current of the terminal B point of the wind farm and energy storage, and determines whether the grid connection point voltage exceeds the limit at this time; based on the determination result, the power compensation method is divided into two categories: when the grid connection point voltage does not exceed the limit, proceed to step S2; when the grid connection point voltage exceeds the limit, proceed to step S3. S2, when the grid connection point voltage does not exceed the limit ;in and The upper and lower thresholds represent the voltage at the grid connection point. This represents the voltage of the PCC at the grid connection point at the current moment; the power compensation method at this time is as follows: S201: Detect whether the wind power is operating in MPPT mode. If it is in MPPT mode, maintain it; if the wind power is not operating in MPPT mode, control the wind power to operate in MPPT mode. S202, the energy storage control system detects the SOC(t) of each energy storage unit module in the energy storage, determines whether the SOC(t) exceeds the set threshold, and adjusts the active power output value of the AC side of the combined system at the next moment according to the judgment result; S3, when the grid connection point voltage exceeds the limit. At this point, the output power is adjusted based on the combined system output capacity and power factor as constraints. The specific power compensation method is as follows: S301, the power dispatch system obtains the voltage and current values ​​at the grid connection point and the terminal B point of the wind farm and energy storage by observing them, and calculates the active power at the grid connection point and point B. and reactive power value ; S302, Calculate the individual active power compensation value. and individual reactive power compensation value The calculation formula is as follows:

[0006] The calculation method for ΔU(t) in the formula is as follows: when hour, ; when hour, ; In the formula, and These represent the active and reactive power values ​​at the PCC point when performing single power regulation at the current moment; and These represent the active and reactive power values ​​at point B when a single power adjustment is performed at the current moment; S4, Calculate the apparent power output of the combined system under both compensation methods at the next time step. and : This is the apparent power when only active power compensation is performed, and its value is... and Apparent power; This is the apparent power when only reactive power compensation is performed, and its value is... and Apparent power; S5, with the maximum output capacity of the combined system Based on constraints, power compensation control methods can be divided into three types, among which control omission markers... The calculation method is as follows: when and hour, If the value is 1, implement control strategy 1; when and hour, If the value is 2, implement control strategy 2; when and Only one has a smaller output capacity than the combined system. At that time, The value is 3, so control strategy 3 is implemented; S6. According to the judgment conditions, execute control strategy 1, control strategy 2, or control strategy 3 in step S5 respectively. S7. The active and reactive power compensation values ​​of the combined system calculated using the above strategy are allocated to the wind farm and energy storage; the specific method is as follows: S701, the upper limit of active power output of each wind turbine is obtained from the wind power detection system. and upper limit of reactive power output ; S702, the active power allocation method is as follows: Assume the wind farm has a total of n wind turbines. For the i-th wind turbine, if... Less than Then the active power provided by the i-th wind turbine is , ;if Greater than Then the active power provided by the i-th wind turbine is , ; sequentially obtain the active power provided by n wind turbines, and obtain ,Will Allocate to energy storage; Indicates the active power of the wind farm Divide by the number of wind turbines, n, to obtain the average active power of each wind turbine. The sum of active power provided by n wind turbines; S703, the reactive power allocation method is as follows: if Less than Then the reactive power provided by the i-th wind turbine is , ;if Greater than Then the reactive power provided by the i-th wind turbine is , ; sequentially obtain the active power provided by n wind turbines, and obtain ,Will Allocate to energy storage; Indicates the reactive power of the wind farm Divide by the number of wind turbines, n, to obtain the average reactive power value per wind turbine. The sum of reactive power provided by n wind turbines.

[0007] Preferably, the specific method of step S202 is as follows: If the i-th energy storage unit module The value falls within the set threshold range. If the active power output of this energy storage unit remains unchanged, then the active power output of this unit remains unchanged. If the i-th energy storage unit module Values ​​greater than 1.1 times the upper limit of the threshold Then the active power output of this energy storage module increases to twice that of the previous moment; If the i-th energy storage unit module Value less than 0.9 times the lower limit of the threshold If this happens, the active power output of this energy storage module becomes 0. If it is not within this range, but does not exceed 10%, then it is considered... or If the active power output of this energy storage module remains in the same state as the previous moment, then the active power output of this single energy storage module will remain in the same state as the previous moment.

[0008] Preferably, the three control strategies in step S6 are as follows: S601, Control Strategy 1: This strategy aims to optimize the power factor at the PCC point. If the direction of reactive power compensation differs from the current reactive power direction, the combined system reactive power compensation value is determined based on the magnitude of the reactive power compensation and the current reactive power magnitude at the PCC point; otherwise, the current reactive power output is maintained, as detailed below: if and The signs are opposite and The absolute value is greater than The absolute value of the reactive power output of the combined system is then... for ;if and The signs are opposite and The absolute value is less than The absolute value of the reactive power output of the combined system is then... for- ;if and If the signs are the same, then the reactive power output value of the combined system is... for ; The following are the active power output values ​​of the combined system. The calculation formula, The calculation method is consistent with that in S302;

[0009] S602, Control Strategy 2: This strategy aims to reduce the voltage deviation at the grid connection point, based on the upper limit of active / reactive power compensation in the joint system. and Determine the given values ​​for active / reactive output; and The calculation method is as follows: When The upper limit of the active power compensation of the joint system when it is greater than or equal to 0 is ;when When the value is less than 0, the upper limit of the active power compensation of the joint system is ;when The upper limit of the active power compensation of the joint system when it is greater than or equal to 0 is ;when When the value is less than 0, the upper limit of the active power compensation of the joint system is The specific judgment formula is as follows:

[0010] when The absolute value is greater than When the absolute value of is reached, the active power output by the combined system is... for The output reactive power is ;when The absolute value is less than or equal to When the absolute value of is reached, the active power output by the combined system is... for The output reactive power is ; S603, Control Strategy 3: This control strategy performs either active power compensation or reactive power compensation only, as detailed below: When the apparent power required for individual active power compensation is less than the output capacity of the combined system At that time, the output active power is The reactive power remains at the output value of the previous moment. ; When the apparent power required for individual reactive power compensation is less than the output capacity Smax of the combined system, the output reactive power is: The active power remains at the output value of the previous moment. .

[0011] Preferably, a grid connection point voltage active support system that coordinates energy storage and main control includes a power dispatching system, which executes the grid connection point voltage active support strategy that coordinates energy storage and main control.

[0012] Preferably, the power dispatch system is also electrically connected to the wind turbine multi-unit system, the wind power monitor, the wind power controller, and the energy storage control system; wherein the wind power monitor is electrically connected to the input terminal of the power dispatch system; the wind turbine multi-unit system is electrically connected to the input terminal of the wind power monitor; the wind power controller is electrically connected to the input terminal of the wind turbine multi-unit system; the power dispatch system is electrically connected to the input terminals of the wind power controller and the energy storage control system; the energy storage control system is bidirectionally electrically connected to the energy storage system; the input terminal of the power dispatch system is also electrically connected to the electrical load, line impedance, and AC / DC hybrid power grid.

[0013] The beneficial effects of the above-mentioned active grid connection voltage support strategy and system that coordinates energy storage and main control are as follows: This invention can employ different voltage control strategies based on real-time observations of the grid connection point voltage, and can make full use of the output capacity of the combined system to provide corresponding power compensation for the grid connection point, maintain the stability of the grid connection point voltage, and improve the power factor. It effectively solves the problem in the prior art that it does not consider effectively improving the power factor of the grid connection point, and the problem of implementing different control strategies based on whether the grid connection point voltage exceeds the limit, thereby adjusting the grid connection point voltage in a targeted manner. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the control strategy principle structure of the present invention; Figure 2 This is a schematic diagram of the power scheduling system principle structure of the present invention; Figure 3 This is a schematic diagram of the principle structure of the energy storage control system of the present invention. Detailed Implementation

[0015] Example 1: like Figures 1-3 As shown, a grid connection point voltage active support strategy that coordinates energy storage and main control includes the following steps: S1, the power dispatch system detects the voltage and current of the grid connection point PCC of the wind farm and energy storage, as well as the voltage and current of the terminal B point of the wind farm and energy storage, and determines whether the grid connection point voltage exceeds the limit at this time; based on the determination result, the power compensation method is divided into two categories: when the grid connection point voltage does not exceed the limit, proceed to step S2; when the grid connection point voltage exceeds the limit, proceed to step S3. S2, when the grid connection point voltage does not exceed the limit ;in and The upper and lower thresholds represent the voltage at the grid connection point. This represents the voltage of the PCC at the grid connection point at the current moment; the power compensation method at this time is as follows: S201: Detect whether the wind power is operating in MPPT mode. If it is in MPPT mode, maintain it; if the wind power is not operating in MPPT mode, control the wind power to operate in MPPT mode. S202, the energy storage control system detects the SOC(t) of each energy storage unit module in the energy storage, determines whether the SOC(t) exceeds the set threshold, and adjusts the active power output value of the AC side of the combined system at the next moment according to the judgment result; S3, when the grid connection point voltage exceeds the limit. At this point, the output power is adjusted based on the combined system output capacity and power factor as constraints. The specific power compensation method is as follows: S301, the power dispatch system obtains the voltage and current values ​​at the grid connection point and the terminal B point of the wind farm and energy storage by observing them, and calculates the active power at the grid connection point and point B. and reactive power value ; S302, Calculate the individual active power compensation value. and individual reactive power compensation value The calculation formula is as follows:

[0016] The calculation method for ΔU(t) in the formula is as follows: when hour, ; when hour, ; In the formula, and These represent the active and reactive power values ​​at the PCC point when performing single power regulation at the current moment; and These represent the active and reactive power values ​​at point B when a single power adjustment is performed at the current moment; S4, Calculate the apparent power output of the combined system under both compensation methods at the next time step. and : This is the apparent power when only active power compensation is performed, and its value is... and Apparent power; This is the apparent power when only reactive power compensation is performed, and its value is... and Apparent power; S5, with the maximum output capacity of the combined system Based on constraints, power compensation control methods can be divided into three types, among which control omission markers... The calculation method is as follows: when and hour, If the value is 1, implement control strategy 1; when and hour, If the value is 2, implement control strategy 2; when and Only one has a smaller output capacity than the combined system. At that time, The value is 3, so control strategy 3 is implemented; S6. According to the judgment conditions, execute control strategy 1, control strategy 2, or control strategy 3 in step S5 respectively. S7. The active and reactive power compensation values ​​of the combined system calculated using the above strategy are allocated to the wind farm and energy storage; the specific method is as follows: S701, the upper limit of active power output of each wind turbine is obtained from the wind power detection system. and upper limit of reactive power output ; S702, the active power allocation method is as follows: Assume the wind farm has a total of n wind turbines. For the i-th wind turbine, if... Less than Then the active power provided by the i-th wind turbine is , ;if Greater than Then the active power provided by the i-th wind turbine is , ; sequentially obtain the active power provided by n wind turbines, and obtain ,Will Allocate to energy storage; Indicates the active power of the wind farm Divide by the number of wind turbines, n, to obtain the average active power of each wind turbine. The sum of active power provided by n wind turbines; S703, the reactive power allocation method is as follows: if Less than Then the reactive power provided by the i-th wind turbine is , ;if Greater than Then the reactive power provided by the i-th wind turbine is , ; sequentially obtain the active power provided by n wind turbines, and obtain ,Will Allocate to energy storage; Indicates the reactive power of the wind farm Divide by the number of wind turbines, n, to obtain the average reactive power value per wind turbine. The sum of reactive power provided by n wind turbines.

[0017] Preferably, the specific method of step S202 is as follows: If the i-th energy storage unit module The value falls within the set threshold range. If the active power output of this energy storage unit remains unchanged, then the active power output of this unit remains unchanged. If the i-th energy storage unit module Values ​​greater than 1.1 times the upper limit of the threshold Then the active power output of this energy storage module increases to twice that of the previous moment; If the i-th energy storage unit module Value less than 0.9 times the lower limit of the threshold If this happens, the active power output of this energy storage module becomes 0. If it is not within this range, but does not exceed 10%, then it is considered... or If the active power output of this energy storage module remains in the same state as the previous moment, then the active power output of this single energy storage module will remain in the same state as the previous moment.

[0018] Preferably, the three control strategies in step S6 are as follows: S601, Control Strategy 1: This strategy aims to optimize the power factor at the PCC point. If the direction of reactive power compensation differs from the current reactive power direction, the combined system reactive power compensation value is determined based on the magnitude of the reactive power compensation and the current reactive power magnitude at the PCC point; otherwise, the current reactive power output is maintained, as detailed below: if and The signs are opposite and The absolute value is greater than The absolute value of the reactive power output of the combined system is then... for ;if and The signs are opposite and The absolute value is less than The absolute value of the reactive power output of the combined system is then... for- ;if and If the signs are the same, then the reactive power output value of the combined system is... for ; The following are the active power output values ​​of the combined system. The calculation formula, The calculation method is consistent with that in S302;

[0019] S602, Control Strategy 2: This strategy aims to reduce the voltage deviation at the grid connection point, based on the upper limit of active / reactive power compensation in the joint system. and Determine the given values ​​for active / reactive output; and The calculation method is as follows: When The upper limit of the active power compensation of the joint system when it is greater than or equal to 0 is ;when When the value is less than 0, the upper limit of the active power compensation of the joint system is ;when The upper limit of the active power compensation of the joint system when it is greater than or equal to 0 is ;when When the value is less than 0, the upper limit of the active power compensation of the joint system is The specific judgment formula is as follows:

[0020] when The absolute value is greater than When the absolute value of is reached, the active power output by the combined system is... for The output reactive power is ;when The absolute value is less than or equal to When the absolute value of is reached, the active power output by the combined system is... for The output reactive power is ; S603, Control Strategy 3: This control strategy performs either active power compensation or reactive power compensation only, as detailed below: When the apparent power required for individual active power compensation is less than the output capacity of the combined system At that time, the output active power is The reactive power remains at the output value of the previous moment. ; When the apparent power required for individual reactive power compensation is less than the output capacity Smax of the combined system, the output reactive power is: The active power remains at the output value of the previous moment. .

[0021] Example 2: like Figure 1 As shown, the application objects of this invention include energy storage and wind turbine units connected to AC / DC hybrid power grids. The specific structure of the energy storage and wind turbine units connected to AC / DC hybrid power grids is as follows: Includes a multi-unit wind power system 1, used to convert wind energy into electrical energy; Wind power monitor 3 is used to monitor and calculate the upper limit of active power output Pi and the upper limit of reactive power output Qi of each wind turbine in real time. Wind power controller 2 is used to control the amount of active and reactive power generated by each wind turbine; The power dispatch system 4 is used to observe the voltage and current values ​​at the grid connection point. Based on the different voltage values ​​at the grid connection point, different control strategies are adopted to calculate the active power and reactive power compensation values ​​output by the energy storage and wind farm joint system, and to allocate them reasonably to the wind farm and energy storage. The energy storage control system 5 is used to monitor and calculate the SOC value of each energy storage unit module in real time and to reasonably allocate the output power of each energy storage unit module. Energy storage 6, used to convert chemical energy into electrical energy; Electrical load 7, line impedance 8 and AC / DC hybrid power grid 17 are used to convert low-voltage electricity to high-voltage electricity; In the figure, 12, 13, 14, 15, 16 and 18 represent signal transmission paths, in which the wind power monitor 3 is electrically connected to the input terminal of the power dispatch system 4; the wind turbine multi-machine system 1 is electrically connected to the input terminal of the wind power monitor; the wind controller 2 is electrically connected to the input terminal of the wind turbine multi-machine system 1; the power dispatch system 4 is electrically connected to the input terminals of the wind controller 2 and the energy storage control system 5; and the energy storage control system 5 is bidirectionally electrically connected to the energy storage 6.

[0022] Furthermore, such as Figure 2 The diagram shown is a flowchart of the power dispatching system 4. The specific process is as follows: (1) The power dispatch system 4 observes the voltage and current values ​​of the grid connection point PCC and terminal B. When the voltage of the grid connection point PCC does not exceed the limit, it transmits a signal to the wind power controller 2 to control the wind power to be in MPPT mode, and at the same time transmits a signal to the energy storage control system 5. (2) After observing the SOC value of the energy storage unit module, the energy storage control system 5 adjusts the output power of each energy storage unit module reasonably according to its value; when the voltage of the grid connection point PCC exceeds the limit, the apparent power output of the combined system at the next moment under the two compensation methods is calculated. , ; (3) Based on the combined system output capacity as a constraint, the power compensation control mode is divided into four types, and the corresponding active and reactive power compensation values ​​of the combined energy storage and wind farm system output are calculated. and Then, the wind power detector 3 obtains the upper limit of active power output Pi and the upper limit of reactive power output Qi of each wind power and transmits them to the power dispatch system 4. (4) For the i-th wind power in an n-wind power plant, if Less than Then the active power provided by the i-th wind turbine is , ;if Greater than Then the active power provided by the i-th wind turbine is , The active power provided by n wind turbines is obtained sequentially and transmitted to wind turbine controller 2. Wind turbine controller 2 controls each wind turbine to output the corresponding active power, and Pa = is obtained. The Pa is transmitted to the energy storage control system 5; (5) The energy storage control system 5 rationally allocates Pa to each energy storage unit module; the reactive power allocation method is similar to the active power allocation method, if Less than Then the reactive power provided by the i-th wind turbine is , ;if Greater than Then the reactive power provided by the i-th wind turbine is , The active power provided by n wind turbines is obtained sequentially and transmitted to wind turbine controller 2. Wind turbine controller 2 then controls each wind turbine to output the corresponding reactive power; and Qa = ,Will The data is transmitted to the energy storage control system 5, which then allocates Qa appropriately to each individual energy storage module.

[0023] Furthermore, such as Figure 3 The diagram shown is a flowchart of the energy storage control system. The specific process is as follows: When the voltage is within limits, the energy storage control system detects the SOC(t) of each energy storage module in the energy storage system. If the SOC(t) of the i-th energy storage module is within limits... The value falls within the set threshold range. If the active power output of this energy storage unit remains unchanged, then the active power output of this unit remains unchanged. If the i-th energy storage unit module Values ​​greater than 1.1 times the upper limit of the threshold Then the active power output of this energy storage module increases to twice that of the previous moment; If the i-th energy storage unit module Value less than 0.9 times the lower limit of the threshold If this happens, the active power output of this energy storage module becomes 0. If it is not within this range, but does not exceed 10%, then it is considered... or If the voltage exceeds the limit, the active power output of this energy storage module will remain at the previous output state; if the voltage exceeds the limit, the active and reactive power required by the energy storage to be output will be received from the power dispatch system 4. and It is then distributed equally to each individual energy storage module.

[0024] The above embodiments are merely preferred technical solutions of the present invention and should not be considered as limitations on the present invention. The embodiments and features described in these embodiments can be arbitrarily combined without conflict. The scope of protection of the present invention should be limited to the technical solutions described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. A grid connection point voltage active support strategy that coordinates energy storage and main control, characterized in that, Includes the following steps: S1, the power dispatch system detects the voltage and current of the grid connection point PCC of the wind farm and energy storage, as well as the voltage and current of the terminal B point of the wind farm and energy storage, and determines whether the grid connection point voltage exceeds the limit at this time; based on the determination result, the power compensation method is divided into two categories: when the grid connection point voltage does not exceed the limit, proceed to step S2; when the grid connection point voltage exceeds the limit, proceed to step S3. S2, when the grid connection point voltage does not exceed the limit ;in and The upper and lower thresholds represent the voltage at the grid connection point. This represents the voltage of the PCC at the grid connection point at the current moment; the power compensation method at this time is as follows: S201: Detect whether the wind power is operating in MPPT mode. If it is in MPPT mode, maintain it; if the wind power is not operating in MPPT mode, control the wind power to operate in MPPT mode. S202, the energy storage control system detects the SOC(t) of each energy storage unit module in the energy storage, determines whether the SOC(t) exceeds the set threshold, and adjusts the active power output value of the AC side of the combined system at the next moment according to the judgment result; S3, when the grid connection point voltage exceeds the limit. At this point, the output power is adjusted based on the combined system output capacity and power factor as constraints. The specific power compensation method is as follows: S301, the power dispatch system obtains the voltage and current values ​​at the grid connection point and the terminal B point of the wind farm and energy storage by observing them, and calculates the active power at the grid connection point and point B. and reactive power value ; S302, Calculate the individual active power compensation value. and individual reactive power compensation value The calculation formula is as follows: The calculation method for ΔU(t) in the formula is as follows: when hour, ; when hour, ; In the formula, and These represent the active and reactive power values ​​at the PCC point when performing single power regulation at the current moment; and These represent the active and reactive power values ​​at point B when a single power adjustment is performed at the current moment; S4, Calculate the apparent power output of the combined system under both compensation methods at the next time step. and : This is the apparent power when only active power compensation is performed, and its value is... and Apparent power; This is the apparent power when only reactive power compensation is performed, and its value is... and Apparent power; S5, with the maximum output capacity of the combined system Based on constraints, power compensation control methods can be divided into three types, among which control omission markers... The calculation method is as follows: when and hour, If the value is 1, implement control strategy 1 to optimize the power factor of the PCC point; when and hour, With a value of 2, implement control strategy 2 to reduce the voltage deviation at the grid connection point; when and Only one has a smaller output capacity than the combined system. At that time, The value is 3, so control strategy 3 is implemented, which only performs active power compensation or only performs reactive power compensation. S6. According to the judgment conditions, execute control strategy 1, control strategy 2, or control strategy 3 in step S5 respectively. S7, the active and reactive power compensation values ​​of the combined system calculated by the above strategy are allocated to the wind farm and energy storage.

2. The grid connection point voltage active support strategy for energy storage and main control coordination according to claim 1, characterized in that: The specific method for step S202 is as follows: If the i-th energy storage unit module The value falls within the set threshold range. If the active power output of this energy storage unit remains unchanged, then the active power output of this unit remains unchanged. If the i-th energy storage unit module Values ​​greater than 1.1 times the upper limit of the threshold Then the active power output of this energy storage module increases to twice that of the previous moment; If the i-th energy storage unit module Value less than 0.9 times the lower limit of the threshold If this happens, the active power output of this energy storage module becomes 0. If it is not within this range, but does not exceed 10%, then it is considered... or If the active power output of this energy storage module remains in the same state as the previous moment, then the active power output of this single energy storage module will remain in the same state as the previous moment.

3. The grid connection point voltage active support strategy for energy storage and main control coordination according to claim 1, characterized in that: The three control strategies in step S6 are as follows: S601, Control Strategy 1: This strategy aims to optimize the power factor at the PCC point. If the direction of reactive power compensation differs from the current reactive power direction, the combined system reactive power compensation value is determined based on the magnitude of the reactive power compensation and the current reactive power magnitude at the PCC point; otherwise, the current reactive power output is maintained, as detailed below: if and The signs are opposite and The absolute value is greater than The absolute value of the reactive power output of the combined system is then... for ;if and The signs are opposite and The absolute value is less than The absolute value of the reactive power output of the combined system is then... for- ;if and If the signs are the same, then the reactive power output value of the combined system is... for ; The following are the active power output values ​​of the combined system. The calculation formula, The calculation method is consistent with that in S302; S602, Control Strategy 2: This strategy aims to reduce the voltage deviation at the grid connection point, based on the upper limit of active / reactive power compensation in the joint system. and Determine the given values ​​for active / reactive output; and The calculation method is as follows: When The upper limit of the active power compensation of the joint system when it is greater than or equal to 0 is ;when When the value is less than 0, the upper limit of the active power compensation of the joint system is ;when The upper limit of the active power compensation of the joint system when it is greater than or equal to 0 is ;when When the value is less than 0, the upper limit of the active power compensation of the joint system is The specific judgment formula is as follows: when The absolute value is greater than When the absolute value of is reached, the active power output by the combined system is... for The output reactive power is ;when The absolute value is less than or equal to When the absolute value of is reached, the active power output by the combined system is... for The output reactive power is ; S603, Control Strategy 3: This control strategy performs either active power compensation or reactive power compensation only, as detailed below: When the apparent power required for individual active power compensation is less than the output capacity of the combined system At that time, the output active power is The reactive power remains at the output value of the previous moment. ; When the apparent power required for individual reactive power compensation is less than the output capacity Smax of the combined system, the output reactive power is: The active power remains at the output value of the previous moment. .

4. The grid connection point voltage active support strategy for energy storage and main control coordination according to claim 1, characterized in that: The specific method for step S7 is as follows: S701, the upper limit of active power output of each wind turbine is obtained from the wind power detection system. and upper limit of reactive power output ; S702, the active power allocation method is as follows: Assume the wind farm has a total of n wind turbines. For the i-th wind turbine, if... Less than Then the active power provided by the i-th wind turbine is , ;if Greater than Then the active power provided by the i-th wind turbine is , ; sequentially obtain the active power provided by n wind turbines, and obtain ,Will Allocate to energy storage; Indicates the active power of the wind farm Divide by the number of wind turbines, n, to obtain the average active power of each wind turbine. The sum of active power provided by n wind turbines; S703, the reactive power allocation method is as follows: if Less than Then the reactive power provided by the i-th wind turbine is , ;if Greater than Then the reactive power provided by the i-th wind turbine is , ; sequentially obtain the active power provided by n wind turbines, and obtain ,Will Allocate to energy storage; Indicates the reactive power of the wind farm Divide by the number of wind turbines, n, to obtain the average reactive power value per wind turbine. The sum of reactive power provided by n wind turbines.

5. A grid connection point voltage active support system that coordinates energy storage and main control, characterized in that: It includes a power dispatching system that executes the grid connection point voltage active support strategy that coordinates energy storage and main control as described in any one of claims 1 to 4.

6. The grid connection point voltage active support system for energy storage and main control coordination according to claim 5, characterized in that: The power dispatch system is also electrically connected to the wind turbine multi-unit system, wind power monitor, wind power controller, and energy storage control system. Among them, the wind power monitor is electrically connected to the input terminal of the power dispatch system; the wind turbine multi-unit system is electrically connected to the input terminal of the wind power monitor; the wind power controller is electrically connected to the input terminal of the wind turbine multi-unit system; the power dispatch system is electrically connected to the input terminals of the wind power controller and the energy storage control system; the energy storage control system is bidirectionally electrically connected to the energy storage system; the input terminal of the power dispatch system is also electrically connected to the electrical load, line impedance, and AC / DC hybrid power grid.

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