Power grid transient voltage coordination control method under distributed optical storage high permeability working condition

Abstract

The invention discloses a power grid transient voltage coordination control method under a distributed photovoltaic storage high permeability working condition, and the method comprises the steps: detecting the voltage change condition of a grid-connected point where a distributed photovoltaic power station is located, and combining the short-circuit ratio of the grid-connected point where the distributed photovoltaic power station is located to a collection point; carrying out pre-estimation calculation on the reactive compensation amount required near the grid-connected point where the key point is located; and through optical storage cooperative control and consideration of different photovoltaic reactive power margin conditions, the reactive power compensation capability of the photovoltaic inverter is developed, smooth processing of the output power of the photovoltaic inverter is realized, and the transient voltage stability of a grid-connected point is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of power systems, and more specifically, relates to a method for coordinated control of transient voltage of a power grid under conditions of high penetration of distributed photovoltaic storage. Background Art

[0002] In recent years, the development of distributed photovoltaics has shown a trend of large-scale contiguous development and cluster grid-connected. As the penetration rate of distributed photovoltaics continues to increase, the randomness and volatility of its output will have a significant impact on the safe and stable operation of the power grid. Especially when a power grid fails, if distributed photovoltaics are unplannedly disconnected from the grid, it will further aggravate the energy imbalance of the main power grid and may even cause voltage collapse.

[0003] Traditional distributed photovoltaic-storage coordinated control of transient voltage usually adopts local control strategies, such as droop control or power factor control, and mainly relies on local information of photovoltaic systems and energy storage devices for voltage regulation. However, the coordination between photovoltaic and energy storage devices is poor, which may lead to non-optimal resource scheduling or conflict with each other, reducing the overall efficiency of the system. In this technical context, the energy storage system can not only smooth the fluctuations of photovoltaic power generation, but also play an important role in voltage regulation to compensate for the randomness of photovoltaic power generation. At the same time, distributed photovoltaic-storage coordinated control can achieve dynamic and stable regulation of regional power grids by combining local control with global optimization, thereby enhancing the safety and stability of the power grid. Therefore, distributed photovoltaic-storage coordinated control voltage regulation technology has become an important direction for the development of modern power grid technology, which can not only improve the acceptance capacity of distributed power generation systems, but also enhance the adaptability of power grids to uncertainty and volatility. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for coordinated control of transient voltage of a power grid under conditions of high penetration of distributed photovoltaic energy storage. By combining a distributed photovoltaic power generation system with an energy storage device, the voltage and power balance are jointly adjusted by utilizing the improved reactive compensation capability of the distributed photovoltaic inverter and the rapid response capability of the energy storage system.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for coordinated control of transient voltage of a power grid under high penetration rate of distributed photovoltaic storage, which is characterized by comprising the following steps:

[0006] (1) Collect environmental parameters of each distributed photovoltaic power station, including temperature T i , light intensity L i , i=1,2,…,n, n is the number of photovoltaic power stations;

[0007] (2) Select key points in distributed photovoltaic power stations and group each distributed photovoltaic power station according to key points and environmental parameters;

[0008] (3) Prioritize the photovoltaic power plants in each group after grouping;

[0009] (4) Calculate the total amount of reactive power required to maintain voltage stability at key points when the grid is in a transient state;

[0010] (5) According to the total reactive power demand, the reactive power compensation mode of each photovoltaic station is switched in the order of GP1, GP2, GP3, and GP4;

[0011] (6) The active power of each photovoltaic power station is compensated through the energy storage system, thereby stabilizing the grid voltage.

[0012] The object of the invention of the present invention is achieved in this way:

[0013] The present invention discloses a method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage. The method detects voltage change of grid connection point where distributed photovoltaic power station is located, combines short-circuit ratio of grid connection point and collection point where distributed photovoltaic power station is located, and estimates reactive power compensation required near grid connection point at key point. Then, through coordinated control of photovoltaic storage and considering different reactive power margin conditions of photovoltaic, the reactive power compensation capability of photovoltaic inverter is developed and smooth processing of its output power is realized, so as to improve transient voltage stability of grid connection point.

[0014] At the same time, the method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage in the present invention also has the following beneficial effects:

[0015] (1) When a power grid failure causes a voltage drop at a renewable energy grid connection point, each distributed photovoltaic power station outputs reactive power compensation through priority grouping as the main means of voltage regulation to achieve high voltage control efficiency and reduce unnecessary photovoltaic power fluctuations.

[0016] (2) Energy storage coordination control is added when the photovoltaic inverter switches its working mode. On the one hand, it makes the power at the grid connection point smoother and reduces voltage fluctuations. On the other hand, the active power output by the energy storage is used as an indirect means of voltage regulation to increase the voltage stability on the load side and better serve the user side.

[0017] (3) After the voltage stability of the grid-connected point of the distributed photovoltaic power station is improved, the DC transient voltage stability can be further improved through interactive coupling between the distributed photovoltaic power station and the DC cross-voltage level. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart of a method for coordinated control of transient voltage of a power grid under high penetration rate of distributed photovoltaic storage in the present invention;

[0019] Figure 2This is a topological diagram of a power grid containing distributed photovoltaic storage according to an embodiment of the present application;

[0020] Figure 3 It is a comparison diagram of the key nodes of the example provided in the embodiment of the present application and the results before and after the DC bus voltage regulation; DETAILED DESCRIPTION

[0021] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0022] Example

[0023] In this embodiment, if Figure 2 As shown in the figure, the power grid system with distributed photovoltaic storage mainly includes DC bus, AC grid, photovoltaic unit, energy storage unit and related inverter. Figure 2 In the power grid shown, photovoltaics are mostly connected to the end of the network, and the energy storage configuration node is usually the same as the photovoltaic installation node. The relevant parameters are shown in Table 1 below:

[0024]

[0025] Before the specific implementation, the photovoltaic operating environment conditions are simulated in sunny, cloudy and rainy conditions, and random short time periods are selected to verify the transient voltage of the photovoltaic storage coordinated control.

[0026] Next we combine Figure 2 A method for coordinated control of transient voltage of a power grid under high penetration rate of distributed photovoltaic storage is described in detail. Figure 1 As shown, the specific steps include:

[0027] (1) Collect parameters of each distributed photovoltaic power station;

[0028] Collect environmental data of each distributed photovoltaic power station, including temperature T i , light intensity L i , i=1,2,…,n, n is the number of photovoltaic power stations;

[0029] In this embodiment, if Figure 2 As shown, the nodes containing photovoltaic power stations and energy storage are: 2, 3, 5, 6, 7, 10, 12, 13. The collected environmental data are shown in Table 1:

[0030]

[0031]

[0032] Table 1

[0033] (2) Grouping each distributed photovoltaic power station;

[0034] According to the inherent differences in the photovoltaic reactive capacity of different photovoltaic power stations and the time-varying nature caused by the external environment, the reactive compensation capabilities of different photovoltaic power stations are ranked and grouped as follows:

[0035] (2.1) Traverse the environmental data of each distributed photovoltaic power station and convert the light intensity L i Meet 800W / m 2 ≤L i ≤1000W / m 2 , and the temperature T i Meet 15℃≤T i PV plants with a temperature of ≤30°C are marked as the priority group, and the remaining PV plants are marked as the alternative group;

[0036] In this embodiment, the priority groups are: 6, 7, 10, 12, 13; the alternative groups are: 2, 3, 5.

[0037] (2.2) Add random disturbance to the grid connection point where the distributed photovoltaic power station is located, and select the grid connection point with the largest voltage fluctuation as the key point j. In this embodiment, node 2 is selected as the key point at the current moment;

[0038] The photovoltaic power stations 1 to j-1 between the key point j and the collection point O are classified as upstream units, and the photovoltaic power stations j to n between the key point j and the end of the line are classified as downstream units;

[0039] (2.3) Taking into account the inherent differences and environmental time-variability of different photovoltaic power stations, the photovoltaic power station in the downstream unit and in the priority group is marked as GP1; the photovoltaic power station in the upstream unit and in the priority group is marked as GP2; the photovoltaic power station in the downstream unit and in the alternative group is marked as GP3; the photovoltaic power station in the upstream unit and in the alternative group is marked as GP4;

[0040] In this embodiment, at the current moment, the nodes are grouped into: GP1 (6, 7, 10, 12, 13), GP2, GP3 (2, 3, 5), GP4.

[0041] (3) Prioritize the photovoltaic power plants in each group;

[0042] (3.1) Calculate the voltage sensitivity S between the grid connection point i and the key point j of each photovoltaic power station in each group ij ;

[0043]

[0044] Among them, U j Represents the transformer output voltage of the photovoltaic power station at the key point j when the power grid is in a steady state; R 1,i , X 1,i Respectively represent the line resistance and line reactance between the first grid connection point and the i-th grid connection point; R 1,j , R 1,j They represent the line resistance and line reactance between the first grid connection point and the key point j respectively;

[0045] In this embodiment, assuming that the unit line impedance is (0.602+j0.232)Ω / km, according to the above formula, the voltage sensitivity moments of each node are respectively:

[0046] S 32 =[0.26378 0.13179]

[0047] S 52 =[0.28779 0.13067]

[0048] S 62 =[0.32473 0.13096]

[0049] S 72 =[0.34853 0.13432]

[0050] S 102 =[0.52107 0.14377]

[0051] S 122 =[0.77369 0.15594]

[0052] S 132 =[0.78534 0.15766]

[0053] (3.2), set the priority of the photovoltaic power station corresponding to the key point j to be the highest, and note that the photovoltaic power station corresponding to node 2 has the highest priority;

[0054] According to the voltage sensitivity, the higher the voltage sensitivity in the same group, the higher the priority, that is, the higher the priority of the inverter reactive power compensation function. Therefore, we classify the photovoltaic power stations in each group according to the voltage sensitivity S. ij Arrange in descending order, and finally get the priority ranking of all PV power stations.

[0055] In this embodiment, the photovoltaic nodes in the example are prioritized as follows: 2, 13, 12, 7, 6, 10, 5, 3.

[0056] (4) Calculate the total amount of reactive power required to maintain voltage stability at key point j when the grid is in a transient state;

[0057] (4.1) Calculate the reactive power impact factor K of key point j on the grid connection point i of each distributed photovoltaic power station Q,ji ;

[0058]

[0059] Among them, x io represents the line reactance between the grid connection point i and the collection point O, x jo Indicates the line reactance from the key point j to the collection point O; ΔU i Indicates the voltage fluctuation value at the grid connection point i when the grid is in a transient state, ΔU j It represents the voltage fluctuation value at the key point j when the power grid is in transient state;

[0060] (4.2), calculate the short-circuit ratio SCR at the key point j and the collection point O j 、SCR O :

[0061]

[0062] Among them, S ac,j represents the short-circuit capacity at the key point j, S ac,O represents the short-circuit capacity at the collection point O, Q j Represents the reactive power output by the photovoltaic power station at the key point j;

[0063] (4.3) Calculate the total amount of reactive power required to maintain voltage stability at key point j when the grid is in transient state;

[0064]

[0065] Among them, U N is the nominal voltage; E is the potential of the power grid system; It represents the transformer output voltage of the photovoltaic power station at the key point j when the power grid is in a transient state;

[0066] In this embodiment, as the voltage exceeds the limit, when the voltage drops to 0.9 pu, the total reactive power required for the key node 2 to maintain voltage stability is:

[0067]

[0068] (5) According to the reactive power demand value required when the voltage fluctuates, the reactive power compensation mode of each photovoltaic power station is switched in the order of GP1, GP2, GP3, and GP4, i.e., 2, 13, 12, 7, 6, 10, 5, and 3;

[0069] (5.1) First, the working modes of each photovoltaic power station in GP1 are switched according to the priority order;

[0070] (5.1.1) The PV power station ranked first in GP1 is numbered as i;

[0071] (5.1.2) When the power grid is in a transient state, the reactive output range of the photovoltaic inverter of photovoltaic power station i in the MPPT working mode is calculated as:

[0072]

[0073] Among them, S N is the rated apparent power of the photovoltaic inverter of each photovoltaic power station, P i , Q i is the active power and reactive power output by the photovoltaic inverter of photovoltaic power station i;

[0074] Take the maximum reactive power value Q output by the photovoltaic inverter within the reactive output range i,max , if Q i,max >Q' j , then the photovoltaic inverter of photovoltaic power station i provides reactive power to the photovoltaic inverter of photovoltaic power station at key point j, and then enters step (6.1); if Q i,max ≤Q' j , then proceed to step (5.1.3);

[0075] (5.1.3) Switch the PV inverter of PV power station i to work in 1.1 times rated apparent power mode, and then calculate the reactive output range of the PV inverter of PV power station i when the grid is in transient state:

[0076]

[0077] Take the maximum reactive power value Q output by the photovoltaic inverter within the reactive output range i,max , if Q i,max >Q' j , then the photovoltaic inverter of photovoltaic power station i provides reactive power to the photovoltaic inverter of photovoltaic power station at key point j, and then enters step (6.1); if Q i,max ≤Q' j , then go to step (5.1.4);

[0078] (5.1.4) Switch the PV inverter of PV power station i to work in active power reduction mode, and then calculate the reactive power output range of the PV inverter of PV power station i when the grid is in transient state:

[0079]

[0080] Where ΔP i Indicates the active power reduction value of the photovoltaic inverter of photovoltaic power station i;

[0081] Take the maximum reactive power value Q output by the photovoltaic inverter within the reactive output range i,max , if Q i,max >Q' j , then the photovoltaic inverter of photovoltaic power station i provides reactive power to the photovoltaic inverter of photovoltaic power station at key point j, and then enters step (6.2); if Q i,max ≤Q' j , then the maximum reactive power value Q output by the photovoltaic inverter of photovoltaic power station i i,max Provided to the photovoltaic inverter of the photovoltaic power station at the key point j, and then enter step (5.2);

[0082] (5.2) Calculate the total amount of reactive power Q required to maintain voltage stability at key point j after PV power station i provides reactive power to key point j” j =Q' j -Q i,max ;

[0083] (5.3) Taking the total reactive power Q” j Based on the above, the working modes of the photovoltaic power stations in GP1, GP2, GP3 and GP4 are switched in order of priority according to step (5.1);

[0084] In this embodiment, the photovoltaic power station where the key node 2 is located is first dispatched. If the maximum reactive power provided by the key node 2 cannot stabilize the power grid (that is, the maximum reactive power is less than the total reactive power required for the stability of the power grid), the 13th node with the highest priority in GP1 is used to provide reactive power to the key node 2 first, and then the same process is repeated. Finally, reactive power is provided to the key node 2 in the order of priority 2, 13, 12, 7, 6, 10, 5, and 3.

[0085] (6) Provide active power compensation for each photovoltaic power station through the energy storage system;

[0086] (6.1), in MPPT working mode and 1.1 times rated apparent power mode, calculate the line loss P when PV station i provides reactive power to key point j. line,i ;

[0087]

[0088] in, It represents the transformer output voltage of the photovoltaic power station at location i of the photovoltaic power station when the power grid is in a transient state;

[0089] (6.2) In the active power reduction mode, calculate the line loss P when the photovoltaic power station i provides reactive power to the key point j. line,i ;

[0090]

[0091] (6.3) The energy storage system provides line loss P to the photovoltaic inverter of photovoltaic power station i. line,i Equivalent active power compensation.

[0092] In summary, this method is not only applicable to the improvement of transient voltage at renewable energy grid-connected points, but also can further improve the stability of transient voltage at DC voltage busbars through interactive coupling between renewable energy and DC voltage levels: the improvement of voltage stability at distributed renewable energy grid-connected points has a positive impact on transient voltage at upper-level high-voltage DC busbars, mainly in terms of reducing voltage fluctuations, accelerating system recovery, reducing voltage drops and overvoltage risks, reducing harmonics and oscillations, and suppressing chain reactions. This helps to improve the overall voltage stability and reliability of the power grid.

[0093] After implementing the above-mentioned coordinated control method for transient voltage of the power grid under the condition of high penetration of distributed photovoltaic storage, a three-phase short circuit fault occurred in the 220kV DC near area of ​​the power system, causing a voltage drop, and the transient voltage of key nodes was observed under different external conditions. Figure 3 The transient voltage comparison diagram of the selected key node 2 and 220kV DC bus voltage before and after the grid transient voltage coordinated control method under the condition of distributed photovoltaic storage with high penetration rate is shown in Table 2. Two moments P1 and P2 are randomly selected as the analysis and research time nodes, and the control method and traditional control are compared. In the case of P1, the DC bus voltage at 220kV is further tested. The relevant calculation results of the P1 case are shown in Table 2. At this time, the system short-circuit ratio is 2.472.

[0094] Depend on Figure 3 It can be seen that, P1: Under the control of this method, the grid connection point voltage of key node 2 did not experience transient overvoltage during the recovery process. The recovery of 220kV DC bus voltage was faster and smoother overall; P2: Under the control of this method, the voltage fluctuation amplitude of key node 2 was smaller than that of the traditional control method, and its transient overvoltage peak was lower; Table 2: Calculation results of the present invention and the traditional control method when the short circuit ratio was 2.472.

[0095]

[0096] The results show that after the voltage of the key grid-connected point under coordinated control is subjected to voltage shock, the degree of transient overvoltage can be reduced by combining the relevant photovoltaic storage regulation capability, thereby reducing the impact on the upper high-voltage DC bus voltage, helping to reduce the transient voltage fluctuation time of the DC bus, improving the dynamic response performance of the system, and reducing the voltage overshoot phenomenon during the transient period.

[0097] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage, characterized in that: The following steps are involved: (1) Collect environmental parameters of each distributed photovoltaic power station, including temperature T i , light intensity L i , i=1,2,…,n, n is the number of photovoltaic power stations; (2) Select key points in distributed photovoltaic power stations and group each distributed photovoltaic power station according to key points and environmental parameters; (3) Prioritize the photovoltaic power plants in each group after grouping; (4) Calculate the total amount of reactive power required to maintain voltage stability at key points when the grid is in a transient state; (5) According to the total reactive power demand, the reactive power compensation mode of each photovoltaic station is switched in the order of GP1, GP2, GP3, and GP4; (6) The active power of each photovoltaic power station is compensated through the energy storage system, thereby stabilizing the grid voltage.

2. According to claim 1, a method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage, characterized in that: The method for grouping distributed photovoltaic power stations is as follows: (2.1) Traverse the environmental data of each distributed photovoltaic power station and convert the light intensity L i Meet 800W / m 2 ≤L i ≤1000W / m 2 , and the temperature T i Meet 15℃≤T i PV plants with a temperature of ≤30°C are marked as the priority group, and the remaining PV plants are marked as the alternative group; (2.2) Add random disturbances to the grid connection point where the distributed photovoltaic power station is located, and select the grid connection point with the largest voltage fluctuation as the key point j; The photovoltaic power stations 1 to j-1 between the key point j and the collection point O are classified as upstream units, and the photovoltaic power stations j to n between the key point j and the end of the line are classified as downstream units; (2.3) The photovoltaic power station in the downstream unit and in the priority group is marked as GP1; the photovoltaic power station in the upstream unit and in the priority group is marked as GP2; the photovoltaic power station in the downstream unit and in the alternative group is marked as GP3; the photovoltaic power station in the upstream unit and in the alternative group is marked as GP4.

3. According to claim 1, a method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage, characterized in that: The method for prioritizing the photovoltaic power station is as follows: (3.1) Calculate the voltage sensitivity S between the grid connection point i and the key point j of each photovoltaic power station in each group ij ; Among them, U j Represents the transformer output voltage of the photovoltaic power station at the key point j when the power grid is in a steady state; R 1,i , X 1,i Respectively represent the line resistance and line reactance between the first grid connection point and the i-th grid connection point; R 1,j , R 1,j They represent the line resistance and line reactance between the first grid connection point and the key point j respectively; (3.2) Set the priority of the photovoltaic power station corresponding to the key point j to be the highest, and the photovoltaic power stations in each group are classified according to the voltage sensitivity S ij Arrange in descending order, and finally get the priority ranking of all PV power stations.

4. According to claim 1, a method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage, characterized in that: The method for calculating the total amount of reactive power required to maintain voltage stability at the key point is: (4.1) Calculate the reactive power impact factor K of key point j on the grid connection point i of each distributed photovoltaic power station Q,ji ; Among them, x io represents the line reactance between the grid connection point i and the collection point O, x jo Indicates the line reactance from the key point j to the collection point O; ΔU i Indicates the voltage fluctuation value at the grid connection point i when the grid is in a transient state, ΔU j It represents the voltage fluctuation value at the key point j when the power grid is in transient state; (4.2), calculate the short-circuit ratio SCR at the key point j and the collection point O j 、SCR O : Among them, S ac,j represents the short-circuit capacity at the key point j, S ac,O represents the short-circuit capacity at the collection point O, Q j Represents the reactive power output by the photovoltaic power station at the key point j; (4.3) Calculate the total amount of reactive power required to maintain voltage stability at key point j when the grid is in transient state; Among them, U N is the nominal voltage; E is the potential of the power grid system; It represents the transformer output voltage of the photovoltaic power station at the key point j when the power grid is in a transient state.

5. The method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage according to claim 1 is characterized in that: The process of switching the reactive power compensation mode in step (5) is as follows: (5.1) First, the working modes of each photovoltaic power station in GP1 are switched according to the priority order; (5.1.1) The PV power station ranked first in GP1 is numbered as i; (5.1.2) When the power grid is in a transient state, the reactive output range of the photovoltaic inverter of photovoltaic power station i in the MPPT working mode is calculated as: Among them, S N is the rated apparent power of the photovoltaic inverter of each photovoltaic power station, P i , Q i is the active power and reactive power output by the photovoltaic inverter of photovoltaic power station i; Take the maximum reactive power value Q output by the photovoltaic inverter within the reactive output range i,max , if Q i,max >Q' j , then the photovoltaic inverter of photovoltaic power station i provides reactive power to the photovoltaic inverter of photovoltaic power station at key point j, and then enters step (6.1); if Q i,max ≤Q' j , then proceed to step (5.1.3); (5.1.3) Switch the PV inverter of PV power station i to work in 1.1 times rated apparent power mode, and then calculate the reactive output range of the PV inverter of PV power station i when the grid is in transient state: Take the maximum reactive power value Q output by the photovoltaic inverter within the reactive output range i,max , if Q i,max >Q' j , then the photovoltaic inverter of photovoltaic power station i provides reactive power to the photovoltaic inverter of photovoltaic power station at key point j, and then enters step (6.1); if Q i,max ≤Q' j , then go to step (5.1.4); (5.1.4) Switch the PV inverter of PV power station i to work in active power reduction mode, and then calculate the reactive power output range of the PV inverter of PV power station i when the grid is in transient state: Where ΔP i Indicates the active power reduction value of the photovoltaic inverter of photovoltaic power station i; Take the maximum reactive power value Q output by the photovoltaic inverter within the reactive output range i,max , if Q i,max >Q' j , then the photovoltaic inverter of photovoltaic power station i provides reactive power to the photovoltaic inverter of photovoltaic power station at key point j, and then enters step (6.2); if Q i,max ≤Q' j , then the maximum reactive power value Q output by the photovoltaic inverter of photovoltaic power station i i,max Provided to the photovoltaic inverter of the photovoltaic power station at the key point j, and then enter step (5.2); (5.2) Calculate the total reactive power Q' required to maintain voltage stability at key point j after PV power station i provides reactive power to key point j. j '=Q' j -Q i,max ; (5.3), with the total reactive power Q' j ' is used as a benchmark, and the working modes of the photovoltaic power stations in GP1, GP2, GP3, and GP4 are switched in order of priority according to step (5.1).

6. The method for coordinated control of transient voltage of power grid under high penetration rate of distributed photovoltaic storage according to claim 1 is characterized in that: The method for the energy storage system to perform active power compensation on each photovoltaic power station is: (6.1), in MPPT working mode and 1.1 times rated apparent power mode, calculate the line loss P when PV station i provides reactive power to key point j. line,i ; in, It represents the transformer output voltage of the photovoltaic power station at location i of the photovoltaic power station when the power grid is in a transient state; (6.2) In the active power reduction mode, calculate the line loss P when the photovoltaic power station i provides reactive power to the key point j. line,i ; (6.3) The energy storage system provides line loss P to the photovoltaic inverter of photovoltaic power station i. line,i Equivalent active power compensation.

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