Power system voltage coordination control method based on photovoltaic voltage regulation capacity distribution

Abstract

The invention discloses a power system voltage coordination control method based on photovoltaic voltage regulation capacity distribution, and belongs to the technical field of power system voltage control, and the method comprises the steps: S1, determining a photovoltaic reactive power output threshold value based on photovoltaic reactive power output constraint factors, and obtaining a photovoltaic reactive power output margin based on photovoltaic operation parameters and the photovoltaic reactive power output threshold value; s2, obtaining photovoltaic pre-distributed reactive power based on the photovoltaic reactive power output margin and the reactive power vacancy of the power grid; and S3, obtaining a photovoltaic voltage regulating variable based on the photovoltaic pre-distributed reactive power, and regulating the voltage of the power system based on the photovoltaic voltage regulating variable. The problem that voltage control is not coordinated due to the fact that photovoltaic residual reactive power is not reasonably distributed is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power system voltage control, and in particular to a power system voltage coordination control method based on photovoltaic voltage regulation capacity allocation. Background Art

[0002] With the vigorous development of photovoltaic power generation, the installed capacity of power generation continues to grow year by year. The access of large-scale photovoltaic power stations will have an impact on the voltage of the power system and may even cause voltage stability problems. For example, a multi-time scale distribution network voltage optimization method considering photovoltaic multi-state regulation is disclosed in Patent No. CN113224769B, which includes: establishing a distributed photovoltaic multi-operation state model according to the regulation ability of distributed photovoltaics under different operating states; establishing a multi-time scale distribution network reactive voltage coordination optimization model based on the distributed photovoltaic multi-operation state model and conventional reactive voltage regulation equipment; solving the optimization model of each stage by using an improved particle swarm algorithm, taking the objective function as the particle fitness function, and formulating output action plans for the reactive control equipment and distributed photovoltaics at each node according to the optimization results of the reactive control equipment and distributed photovoltaic multi-state output. The above scheme formulates a reactive voltage optimization scheme based on the characteristics of reactive regulation equipment with different characteristics and the characteristics of distributed photovoltaic multi-state regulation capabilities, improves the operating voltage of each node at each time of the distribution network, and reduces the system voltage offset and fluctuation problems, but the above scheme does not reasonably distribute the residual reactive power of photovoltaics, resulting in the problem of uncoordinated voltage control. Summary of the invention

[0003] In view of the problem of uncoordinated voltage control caused by the failure to reasonably allocate the surplus reactive power of photovoltaics in the prior art, the present invention provides a method for coordinated voltage control of a power system based on the allocation of photovoltaic voltage regulation capacity, which accurately obtains the reactive output margin of photovoltaics through the operating parameters of photovoltaics and the reactive output threshold, and then accurately obtains the pre-allocated reactive power of photovoltaics based on the reactive output margin of photovoltaics and the reactive power shortage of the power grid, thereby solving the problem of uncoordinated voltage control caused by the failure to reasonably allocate the surplus reactive power of photovoltaics. By formulating a reasonable photovoltaic pre-allocation reactive power plan, the accuracy and coordination of voltage control are improved, ensuring that the photovoltaic system can provide an appropriate amount of reactive power according to the actual needs of the power grid, avoiding excess or shortage of reactive power, and improving the utilization rate of photovoltaic resources.

[0004] In order to solve the above technical problems, the present invention provides a method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation, comprising the following steps: S1: Determine the reactive output threshold of photovoltaic based on the reactive output constraint factor of photovoltaic, and obtain the reactive output margin of photovoltaic based on the operating parameters of photovoltaic and the reactive output threshold of photovoltaic; S2: Obtain the pre-allocated reactive power of the photovoltaic system based on the reactive power margin of the photovoltaic system and the reactive power shortage of the power grid; S3: Obtain the photovoltaic voltage regulation amount based on the pre-allocated photovoltaic reactive power, and adjust the voltage of the power system based on the photovoltaic voltage regulation amount.

[0005] After adopting the above technical solution, the present invention has the following advantages: The reactive output capacity of photovoltaics fluctuates with the changes in the operating parameters of photovoltaics. The reactive output threshold is set according to factors such as the physical characteristics of photovoltaics and the capacity limit of the inverter, representing the maximum reactive power that photovoltaics can stably output under certain conditions. At the same time, since the reactive output margin of photovoltaics reflects the additional reactive power that photovoltaics can provide under current conditions, the reactive output margin of photovoltaics is obtained based on the operating parameters of photovoltaics and the reactive output threshold of photovoltaics. Then, the pre-allocated reactive power of photovoltaics is accurately obtained based on the reactive output margin of photovoltaics and the reactive power shortage of the power grid. By formulating a reasonable pre-allocated reactive power plan for photovoltaics, the accuracy and coordination of voltage control are improved. The reactive power deficit of the power grid refers to the reactive power required for the normal operation of all loads and equipment in the power grid due to the fact that the reactive power resources actually available in the power grid are insufficient. Therefore, by accurately obtaining the pre-allocated reactive power of the photovoltaic system based on the reactive output margin of the photovoltaic system and the reactive power deficit of the power grid, it is ensured that the photovoltaic system can provide an appropriate amount of reactive power according to the actual needs of the power grid, avoiding excess or shortage of reactive power and improving the utilization rate of photovoltaic resources. The problem of uncoordinated voltage control caused by the unreasonable distribution of the remaining reactive power of photovoltaics is solved.

[0006] Preferably, in S1, determining the photovoltaic reactive output threshold based on the photovoltaic reactive output constraint factor includes: setting a power factor threshold according to an operation strategy of the photovoltaic power station, and obtaining a rated capacity of an inverter; Calculate the active power of photovoltaics within a preset time period based on the light intensity and the photovoltaic array efficiency of the photovoltaics; The reactive output threshold of photovoltaic is determined based on the power factor threshold, the rated capacity of the inverter and the active power of photovoltaic in the preset time period. By setting the power factor threshold and considering the rated capacity of the inverter, it is ensured that the photovoltaic can maximize the active power output while maintaining a high power factor, thereby improving the overall operation efficiency of photovoltaic.

[0007] Preferably, determining the photovoltaic reactive output threshold based on the power factor threshold, the rated capacity of the inverter and the photovoltaic active power within a preset time period includes: Photovoltaic reactive power output threshold Where S is the rated capacity of the inverter, PF is the power factor threshold, and P is the active power of the photovoltaic in the preset time period.

[0008] Preferably, in S1, obtaining the photovoltaic reactive power margin based on the photovoltaic operating parameters and the photovoltaic reactive power threshold comprises: It is determined whether the photovoltaic operation parameters and the photovoltaic reactive output threshold meet the first condition. If the first condition is met, the first formula is used to obtain the photovoltaic reactive output margin. If the first condition is not met, it is determined whether the photovoltaic operation parameters and the photovoltaic reactive output threshold meet the second condition. If the second condition is met, the second formula is used to obtain the photovoltaic reactive output margin. If the second condition is not met, the photovoltaic reactive output margin is the preset reactive output margin. The operating parameters of the photovoltaic system will change with time and environmental conditions. By designing multiple conditions and corresponding formulas, different operating scenarios can be more flexibly responded to, making the obtained reactive output margin more accurate, and being able to more accurately reflect the reactive output margin of photovoltaics under current operating conditions, thereby enhancing the accuracy of the calculation and improving the flexibility and applicability of the calculation.

[0009] Preferably, the first condition is The first formula is The first condition and the first formula Q A are the reactive power generated by the photovoltaic power plant at the last moment, P G The active power of photovoltaic power in the preset time period. are the reactive power output thresholds of photovoltaics, S N is the rated capacity of the inverter. By considering multiple factors such as the reactive power generated by the photovoltaic power plant at the last moment, the active power of the photovoltaic power plant in the preset time period, and the reactive power output threshold of the photovoltaic power plant, the reactive power output margin of the photovoltaic power plant at the current moment can be calculated more accurately, thereby improving the calculation accuracy.

[0010] Preferably, the second condition is The second formula is

[0011] Preferably, S2 further includes: Calculate the total reactive power of the power system based on the effective value of voltage and current in the power system; The reactive power deficit of the power grid is obtained based on the first difference between the total reactive power of the power system and the reactive power generated by the photovoltaic at the last moment. The reactive power deficit of the power grid refers to the difference between the reactive power required in the power grid and the reactive power currently available. By comparing the total reactive power of the power system and the reactive power generated by the photovoltaic at the last moment, the current reactive power deficit of the power grid is calculated, so as to carry out targeted reactive power allocation later, thus saving reactive power resources.

[0012] Preferably, S2 includes: Reactive power pre-allocated by the i-th photovoltaic Where ΔP is the reactive power shortage of the power grid, Q R，i is the reactive power margin of the i-th photovoltaic unit; The total reactive power margin of photovoltaic power is calculated. If the second difference between the total reactive power margin of photovoltaic power and the reactive power shortage of the power grid is greater than the preset difference, the pre-allocated reactive power of the energy storage unit is obtained based on the second difference and the preset difference. The preset difference is set to cope with sudden changes in the reactive power demand of the power grid or the uncertainty of the reactive power of photovoltaic power. When the difference between the total reactive power margin of photovoltaic power and the reactive power shortage of the power grid is greater than the preset difference, it means that the reactive power margin of photovoltaic power is far from meeting the reactive power demand of the power system. Therefore, the pre-allocated reactive power of the energy storage unit is obtained based on the second difference and the preset difference. By starting the reactive power pre-allocation of the energy storage unit, the risk of voltage fluctuation is reduced and the stability and reliability of the system are improved.

[0013] Preferably, S3 includes: S31: obtaining a reactive power allocation value based on the pre-allocated reactive power of photovoltaic power generation, and calculating a third difference between the pre-allocated reactive power of photovoltaic power generation and the reactive power allocation value; S32: Calculate a voltage adjustment value based on the third difference, and adjust the voltage of the power system based on the voltage adjustment value. Through accurate reactive power distribution and voltage adjustment based on the difference, the voltage stability of the power system can be significantly improved, which helps to reduce the impact of voltage fluctuations on power equipment and users, and improves the power supply quality.

[0014] Preferably, in S32, calculating the voltage adjustment value based on the third difference includes: The voltage regulation value ΔV=m*ΔW, where m is the droop coefficient, and ΔW is the third difference between the pre-allocated reactive power of photovoltaics and the reactive allocation value.

[0015] The beneficial effects of this program: The reactive output capacity of photovoltaics fluctuates with the changes in the operating parameters of photovoltaics. The reactive output threshold is set according to factors such as the physical characteristics of photovoltaics and the capacity limit of the inverter, representing the maximum reactive power that photovoltaics can stably output under certain conditions. At the same time, since the reactive output margin of photovoltaics reflects the additional reactive power that photovoltaics can provide under current conditions, the reactive output margin of photovoltaics is obtained based on the operating parameters of photovoltaics and the reactive output threshold of photovoltaics. Then, the pre-allocated reactive power of photovoltaics is accurately obtained based on the reactive output margin of photovoltaics and the reactive power shortage of the power grid. By formulating a reasonable pre-allocated reactive power plan for photovoltaics, the accuracy and coordination of voltage control are improved. The reactive power deficit of the power grid refers to the reactive power required for the normal operation of all loads and equipment in the power grid due to the fact that the reactive power resources actually available in the power grid are insufficient. Therefore, by accurately obtaining the pre-allocated reactive power of the photovoltaic system based on the reactive output margin of the photovoltaic system and the reactive power deficit of the power grid, it is ensured that the photovoltaic system can provide an appropriate amount of reactive power according to the actual needs of the power grid, avoiding excess or shortage of reactive power and improving the utilization rate of photovoltaic resources. The operating parameters of photovoltaic power generation will change with time and environmental conditions. By designing multiple conditions and corresponding formulas, different operating scenarios can be handled more flexibly, making the obtained reactive power margin more accurate and more accurately reflecting the reactive power margin of photovoltaic power generation under the current operating conditions, thus enhancing the accuracy of calculation and improving the flexibility and applicability of calculation. The problem of uncoordinated voltage control caused by the unreasonable distribution of the remaining reactive power of photovoltaics is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings. The drawings are only for the purpose of illustrating preferred embodiments and are not to be considered as limiting the present invention. Also, the same reference symbols are used throughout the drawings to represent the same parts.

[0017] Figure 1 It is a flow chart of a method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to the present invention; Figure 2 It is a structure diagram of a power simulation system of a power system voltage coordination control method based on photovoltaic voltage regulation capacity allocation of the present invention; Figure 3 It is a system voltage simulation diagram corresponding to the load increase in the power system voltage coordination control method based on photovoltaic voltage regulation capacity allocation of the present invention; Figure 4 It is a system voltage simulation diagram corresponding to load reduction in the power system voltage coordination control method based on photovoltaic voltage regulation capacity allocation of the present invention. DETAILED DESCRIPTION

[0018] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific implementation method described herein is only an optimal embodiment of the present invention, which is only used to explain the present invention and does not limit the scope of protection of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow charts describe the operations (or steps) as sequential processes, many of the operations (or steps) therein can be implemented in parallel, concurrently, or simultaneously. In addition, the order of the operations can be rearranged. The process can be terminated when its operation is completed, but can also have additional steps not included in the drawings; the process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0020] Embodiment 1: like Figure 1 As shown, the power system voltage coordination control method based on photovoltaic voltage regulation capacity allocation includes the following steps: S1: Determine the reactive output threshold of photovoltaics based on the reactive output constraint factors of photovoltaics, and obtain the reactive output margin of photovoltaics based on the operating parameters of photovoltaics and the reactive output threshold of photovoltaics.

[0021] In S1, the determination of the photovoltaic reactive output threshold based on the photovoltaic reactive output constraint factor includes: Set the power factor threshold according to the operation strategy of the photovoltaic power station and obtain the rated capacity of the inverter; Calculate the active power of photovoltaics within a preset time period based on the light intensity and the photovoltaic array efficiency of the photovoltaics; The reactive power output threshold of photovoltaic is determined based on the power factor threshold, the rated capacity of the inverter and the active power of photovoltaic in a preset time period.

[0022] The reactive power output threshold of photovoltaic is determined based on the power factor threshold, the rated capacity of the inverter and the active power of photovoltaic in the preset time period, including: Photovoltaic reactive power output threshold Where S is the rated capacity of the inverter, PF is the power factor threshold, and P is the active power of the photovoltaic in the preset time period.

[0023] In S1, the method of obtaining the photovoltaic reactive output margin based on the photovoltaic operating parameters and the photovoltaic reactive output threshold includes: judging whether the photovoltaic operating parameters and the photovoltaic reactive output threshold meet a first condition; if the first condition is met, obtaining the photovoltaic reactive output margin using a first formula; if the first condition is not met, judging whether the photovoltaic operating parameters and the photovoltaic reactive output threshold meet a second condition; if the second condition is met, obtaining the photovoltaic reactive output margin using a second formula; if the second condition is not met, the photovoltaic reactive output margin is a preset reactive output margin.

[0024] The first condition is The first formula is The first condition and the first formula Q Aare the reactive power generated by the photovoltaic power plant at the last moment, P G The active power of photovoltaic power in the preset time period. are the reactive power output thresholds of photovoltaics, S N is the rated capacity of the inverter.

[0025] The second condition is The second formula is

[0026] The reactive power output constraints of photovoltaics include the active power of photovoltaics, the rated capacity of the inverter, and the power factor threshold within the preset time period. The preset reactive output margin is 0. The power factor threshold is an indicator to measure the efficiency of the equipment. It represents the proportional relationship between the active power of photovoltaics and the rated capacity of the inverter within the preset time period. When it is in the peak power consumption period, the set power factor threshold is close to 1. If there is a reactive compensation device, such as an SVG static reactive generator, the power factor threshold can also be set to 1. When it is in the low-peak power consumption period, the set power factor threshold is less than the power factor threshold set during the peak power consumption period. The light intensity is the average light intensity within the preset time period, and the photovoltaic array efficiency is the average efficiency within the preset time period. If the rated power of the photovoltaic array is 100kW, the average light intensity within the preset time period is 800W / m 2 , and the photovoltaic array efficiency calculated by the average light intensity in the preset time period is 15%. In order to calculate the active power of photovoltaics in the preset time period, the instantaneous power generated by the photovoltaic array under the current light intensity is obtained. Where P rated is the rated power of the photovoltaic array, I is the average light intensity in the preset time period, and I STC is the light intensity under standard test conditions, η is the efficiency of the photovoltaic array, the instantaneous power is 12kW, the product of the instantaneous power and the preset time period is the active power of the photovoltaic power in the preset time period, and the reactive power output threshold of the photovoltaic power is obtained after obtaining the active power of the photovoltaic power in the preset time period. The reactive output margin is calculated by combining the reactive output threshold of photovoltaic power generation with the operating parameters of photovoltaic power generation. If the reactive power Q generated by photovoltaic power generation at the last moment is A The active power P of the photovoltaic power generation in the preset time period is 25kW. G The reactive power output threshold of photovoltaic is 50kW. The inverter rated capacity is 30kW. N 300kW, It is approximately equal to 29kW. It is approximately equal to 46kW, so the first condition is met at this time, so the reactive power margin of photovoltaic is approximately 4kW. The operating parameters of photovoltaic will change with time and environmental conditions. By designing multiple conditions and corresponding formulas, it is possible to respond to different operating scenarios more flexibly, making the obtained reactive power margin more accurate, and more accurately reflecting the reactive power margin of photovoltaic under the current operating conditions, enhancing the accuracy of the calculation, while improving the flexibility and applicability of the calculation.

[0027] S2: Obtain the pre-allocated reactive power of photovoltaics based on the reactive power margin of photovoltaics and the reactive power shortage of the power grid.

[0028] The S2 further includes: Calculate the total reactive power of the power system based on the effective value of voltage and current in the power system; The reactive power deficit of the power grid is obtained based on a first difference between the total reactive power of the power system and the reactive power generated by the photovoltaic power system at a previous moment.

[0029] The S2 includes: Reactive power pre-allocated by the i-th photovoltaic Where ΔP is the reactive power shortage of the power grid, Q R，i is the reactive power margin of the i-th photovoltaic unit; The total reactive power margin of photovoltaic power generation is calculated. If the second difference between the total reactive power margin of photovoltaic power generation and the reactive power shortage of the power grid is greater than the preset difference, the pre-allocated reactive power of the energy storage unit is obtained based on the second difference and the preset difference.

[0030] In this embodiment, the total reactive power of the power system P1 = V1I1sinθ, where V1 is the effective value of voltage, I1 is the effective value of current, and θ is the phase difference between voltage and current. At this time, the reactive power shortage of the power grid ΔQ grid =P1-Q1, where Q1 is the reactive power generated by the photovoltaic power plant at the last moment. By comparing the total reactive power of the power system with the reactive power generated by the photovoltaic power plant at the last moment, the current reactive power shortage of the power grid is calculated, so that targeted reactive power allocation can be carried out later, saving reactive power resources.

[0031] S3: Obtain the photovoltaic voltage regulation amount based on the pre-allocated photovoltaic reactive power, and adjust the voltage of the power system based on the photovoltaic voltage regulation amount.

[0032] The S3 includes: S31: obtaining a reactive power allocation value based on the pre-allocated reactive power of photovoltaic power generation, and calculating a third difference between the pre-allocated reactive power of photovoltaic power generation and the reactive power allocation value; S32: Calculate a voltage adjustment value based on the third difference, and adjust the voltage of the power system based on the voltage adjustment value.

[0033] In S32, calculating the voltage adjustment value based on the third difference includes: The voltage regulation value ΔV=m*ΔW, where m is the droop coefficient, and ΔW is the third difference between the pre-allocated reactive power of photovoltaics and the reactive allocation value.

[0034] According to the reactive power of each photovoltaic, the expected output value of each photovoltaic storage unit is obtained, the voltage control of each photovoltaic storage unit is allocated, and the day-ahead robust optimization model, intraday rolling optimization model and real-time feedback correction model are established in combination with the multi-time scale optimization algorithm. When establishing the day-ahead robust optimization model, the static VAR compensator SVC is considered to enhance the reactive compensation capability, and the corresponding objective function and constraints are determined; when the intraday rolling optimization model is established, the minimum power system operation cost is taken as the objective function, and the optimization is performed under the relevant constraints; when establishing the real-time feedback correction model, the minimum power adjustment amount at the current moment is selected as the objective function, and real-time feedback and correction are performed, in which the slow-motion equipment maintains the day-ahead robust scheduling plan, and the power scheduling instructions of the adjustable resources are given by the intraday rolling optimization stage. The voltage regulation value is obtained through the above model, and the voltage regulation value is input into each photovoltaic storage unit as the compensation value of the secondary control, so that the voltage of each photovoltaic unit in the system is finally restored to the expected value under various working conditions, thereby achieving the purpose of coordinated voltage control of the power system. Through precise reactive power distribution and differential-based voltage regulation, the voltage stability of the power system can be significantly improved, which helps reduce the impact of voltage fluctuations on power equipment and users and improves the power supply quality.

[0035] In this embodiment, photovoltaic refers to photovoltaic units, and also includes establishing an aggregated control architecture for the power system based on photovoltaic, energy storage and other multi-form reactive resources. Based on the reactive-voltage droop control principle, a power system voltage control model is established to form a voltage control model that can respond to system changes. The constructed multi-form reactive resource aggregated control architecture comprehensively considers the coordination of reactive equipment with different response speeds and the steady-state and dynamic reactive control requirements, and comprehensively covers a variety of key factors affecting system operation, such as system voltage level, power configuration capacity, system load power requirements, etc. It is highly comprehensive and scientific, and includes the following two steps: 1. Comprehensively consider factors such as power system voltage level, power configuration capacity, and load power requirements. Analyze the topological structure of the DC / AC inverter commonly used for photovoltaic storage units to access the AC bus, and build a power simulation system containing photovoltaics, such as Figure 2As shown, there are 3 photovoltaic units and 1 energy storage unit. The 3 photovoltaic units are PV1, PV2 and PV3, and the 1 energy storage unit is ES2. Q is a switch, and each distributed unit in the power system adopts droop control. 2. Study the control method of the photovoltaic storage unit and the grid-connected converter of the power system, so that the photovoltaic unit can play a corresponding role in different scenarios of the power system operation and maintain the stable operation of the system. On the basis of establishing a power simulation system, the droop control method is used to control each photovoltaic storage unit.

[0036] According to the photovoltaic-containing power simulation system built above, corresponding voltage, power and other parameters are set in the droop control of each photovoltaic unit. The relevant data are shown in Table 1: Table 1 Parameters of each photovoltaic unit in the power simulation system The pre-allocated reactive power of photovoltaic is obtained by combining the parameters of each photovoltaic unit in the above power system with the reactive output margin, and the voltage regulation value is obtained through the above model. The voltage regulation value is input into each photovoltaic storage unit as the compensation value of the secondary control, and finally the voltage of each photovoltaic unit in the system is restored to the expected value under various working conditions, and finally the voltage of each photovoltaic unit in the system is restored to the expected value when the load changes, so as to achieve the purpose of coordinated voltage control. For example, Figure 3 As shown in Figure 2, when t=3s, the power system load increases and the photovoltaic unit performs droop control to increase power. When t=3.1s, the inverter control starts, and each photovoltaic storage unit coordinates to restore the voltage according to its own voltage regulation value, as shown in Figure 2. Figure 4 As shown, when t=3s, the load of the AC subgrid decreases, and the photovoltaic storage unit performs droop control to reduce power. When t=3.1s, the inverter control starts, and each photovoltaic storage unit coordinates to restore the voltage according to its own voltage regulation value.

[0037] The specific implementation described above is a preferred implementation of the power system voltage coordination control method based on photovoltaic voltage regulation capacity allocation of the present invention, and is not intended to limit the specific implementation scope of the present invention. The scope of the present invention includes but is not limited to this specific implementation. All equivalent changes made in accordance with the shape and structure of the present invention are within the protection scope of the present invention.

Claims

1. A method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation, characterized in that: The following steps are involved: S1: Determine the reactive output threshold of photovoltaic based on the reactive output constraint factor of photovoltaic, and obtain the reactive output margin of photovoltaic based on the operating parameters of photovoltaic and the reactive output threshold of photovoltaic; S2: Obtain the pre-allocated reactive power of the photovoltaic system based on the reactive power margin of the photovoltaic system and the reactive power shortage of the power grid; S3: Obtain the photovoltaic voltage regulation amount based on the pre-allocated photovoltaic reactive power, and adjust the voltage of the power system based on the photovoltaic voltage regulation amount.

2. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 1, characterized in that: In S1, the determination of the photovoltaic reactive output threshold based on the photovoltaic reactive output constraint factor includes: Set the power factor threshold according to the operation strategy of the photovoltaic power station and obtain the rated capacity of the inverter; Calculate the active power of photovoltaics within a preset time period based on the light intensity and the photovoltaic array efficiency of the photovoltaics; The reactive power output threshold of photovoltaic is determined based on the power factor threshold, the rated capacity of the inverter and the active power of photovoltaic in a preset time period.

3. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 2, characterized in that: The reactive power output threshold of photovoltaic is determined based on the power factor threshold, the rated capacity of the inverter and the active power of photovoltaic in the preset time period, including: Photovoltaic reactive power output threshold Where S is the rated capacity of the inverter, PF is the power factor threshold, and P is the active power of the photovoltaic power plant within the preset time period.

4. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 2, characterized in that: In S1, the photovoltaic reactive power margin is obtained based on the photovoltaic operation parameters and the photovoltaic reactive power threshold, including: It is determined whether the photovoltaic operating parameters and the photovoltaic reactive output threshold meet the first condition. If the first condition is met, the first formula is used to obtain the photovoltaic reactive output margin. If the first condition is not met, it is determined whether the photovoltaic operating parameters and the photovoltaic reactive output threshold meet the second condition. If the second condition is met, the second formula is used to obtain the photovoltaic reactive output margin. If the second condition is not met, the photovoltaic reactive output margin is the preset reactive output margin.

5. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 4 is characterized in that: The first condition is The first formula is The first condition and the first formula Q A are the reactive power generated by the photovoltaic power plant at the last moment, P G The active power of photovoltaic power in the preset time period. are the reactive power output thresholds of photovoltaics, S N is the rated capacity of the inverter.

6. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 5, characterized in that: The second condition is The second formula is 7. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 5, characterized in that: The S2 further includes: Calculate the total reactive power of the power system based on the effective value of voltage and current in the power system; The reactive power deficit of the power grid is obtained based on a first difference between the total reactive power of the power system and the reactive power generated by the photovoltaic power system at a previous moment.

8. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 1, characterized in that: The S2 includes: Reactive power pre-allocated by the i-th photovoltaic Where ΔP is the reactive power shortage of the power grid, Q R，i is the reactive power margin of the i-th photovoltaic unit; The total reactive power margin of photovoltaic power generation is calculated. If the second difference between the total reactive power margin of photovoltaic power generation and the reactive power shortage of the power grid is greater than the preset difference, the pre-allocated reactive power of the energy storage unit is obtained based on the second difference and the preset difference.

9. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 1, characterized in that: The S3 includes: S31: obtaining a reactive power allocation value based on the pre-allocated reactive power of photovoltaic power generation, and calculating a third difference between the pre-allocated reactive power of photovoltaic power generation and the reactive power allocation value; S32: Calculate a voltage adjustment value based on the third difference, and adjust the voltage of the power system based on the voltage adjustment value.

10. The method for coordinated voltage control of a power system based on photovoltaic voltage regulation capacity allocation according to claim 9, characterized in that: In S32, calculating the voltage adjustment value based on the third difference includes: The voltage regulation value ΔV=m*ΔW, where m is the droop coefficient, and ΔW is the third difference between the pre-allocated reactive power of photovoltaics and the reactive allocation value.

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