Configuration Optimization Method and System for Dynamic Reactive Power Compensation Device of New Energy Sending-End Power Grid

Abstract

The present invention relates to the technical field of power grid equipment, and discloses a configuration optimization method and system for a dynamic reactive power compensation device in a new energy sending-end power grid. This method determines the switching situation of the static reactive power of the dynamic reactive power compensation device through the operating power corresponding to multiple reference operating points of the sending-end power grid, determines the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located, and determines the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amount, thereby suppressing large-scale fluctuations in the power of the sending-end power grid, realizing the coordinated control between the dynamic reactive power and the static reactive power considering the large-scale fluctuations of new energy, improving the configuration accuracy of the dynamic reactive power compensation device, realizing the voltage stability brought by the active power output fluctuations accompanied by the strong randomness and volatility of new energy, and effectively controlling the voltage of the sending-end power grid.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid equipment, and particularly relates to a method and system for optimizing the configuration of a dynamic reactive power compensation device for a new energy sending-end power grid. Background Art

[0002] Due to the characteristics of the reverse distribution of energy and load, most new energy requires flexible DC transmission systems for long-distance and large-scale centralized external transmission. At the initial stage of operation of large-scale new energy external transmission bases in Shagehuang, the sending-end power grid usually has no conventional power source support. The power grid characteristics are basically dominated by power electronic devices, and the voltage of the sending-end power grid is completely determined by the flexible DC converter station. Compared with traditional synchronous machine power systems, in a power system dominated by 100% power electronic devices, the imbalance of active and reactive power in the AC power grid will be uniformly reflected as system voltage changes (voltage collapse, excessive voltage fluctuations, overvoltage, etc.). Voltage distribution and disturbance response have become the core issues of system operation characteristics.

[0003] As the electrical distance between the sending-end converter station and the new energy power station becomes farther and farther, the voltage control range of the sending-end rectifier station for the new energy sending-end power grid is limited. The new energy power stations at the far end are often in a weak voltage support state. The weak voltage support intensity at the connection point of the new energy power station may cause stability problems in the sending-end power grid. In addition, compared with the strong randomness and volatility of traditional power grids, the strong randomness of new energy brings power disturbances that may cause large-scale changes in system power flow, and then cause large-scale voltage fluctuations in the system. Therefore, the voltage control of a high-proportion new energy sending-end power grid mainly includes two aspects of requirements: one is that the static voltage stability margin is sufficient under various working conditions; the other is that after various operating conditions and power disturbances, the voltage fluctuation is less than 5% during the normal operation power ramp and random fluctuation of the system.

[0004] Dynamic reactive power compensation devices represented by SVG (Static Var Generator, high-voltage dynamic reactive power compensation device) have the characteristics of fast adjustment speed and flexible control, etc. They can effectively support the voltage of the sending-end power grid, and can effectively solve the voltage stability problems caused by the active power output fluctuations accompanied by the strong randomness and volatility of new energy while improving the stability margin of the sending-end power grid.

[0005] The configuration of dynamic reactive power compensation devices is the main key technology to improve the voltage support ability of the wide-area new energy sending-end power grid and at the same time solve the voltage stability problems caused by the active power output fluctuations of new energy. However, the current configuration accuracy of dynamic reactive power compensation devices is poor, resulting in poor voltage stability caused by the active power output fluctuations accompanied by the strong randomness and volatility of new energy, and it is difficult to effectively control the voltage of the sending-end power grid. Summary of the Invention

[0006] In view of this, the present invention provides a method and system for optimizing the configuration of a dynamic reactive power compensation device for a new energy sending-end power grid, which solves the technical problems that the current configuration accuracy of the dynamic reactive power compensation device is poor, resulting in poor voltage stability caused by the active power fluctuations accompanied by the strong randomness and volatility of new energy, and it is difficult to effectively control the voltage of the sending-end power grid.

[0007] The first aspect of the present invention provides a method for optimizing the configuration of a dynamic reactive power compensation device for a new energy sending-end power grid, including:

[0008] Determine the switching situation of the static reactive power of the dynamic reactive power compensation device corresponding to each of the benchmark operating points according to the operating power corresponding to multiple benchmark operating points of the sending-end power grid, wherein the benchmark operating point is a node in the sending-end power grid with an operating power below the rated power;

[0009] For each steady-state operation mode point, when the power of the sending-end power grid fluctuates greatly, determine the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located, wherein the steady-state operation mode point is the benchmark operating point operating in the switching situation of the static reactive power of the dynamic reactive power compensation device;

[0010] Determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts of the voltage clamping control buses corresponding to multiple steady-state operation mode points.

[0011] Preferably, the determining the switching situation of the static reactive power of the dynamic reactive power compensation device corresponding to each of the benchmark operating points according to the operating power corresponding to multiple benchmark operating points of the sending-end power grid includes:

[0012] Normalize the operating power of the new energy power station with the rated power of the new energy power station, and equally divide the normalized operating power into multiple power per-unit value components;

[0013] Determine multiple benchmark operating points of the sending-end power grid according to multiple power per-unit value components;

[0014] Perform power flow calculation on the sending-end power grid according to the power per-unit values corresponding to multiple benchmark operating points, and obtain the switching situation of the static reactive power of the dynamic reactive power compensation device corresponding to each benchmark operating point, and the switching situation includes the static reactive power switching capacity and the number of static reactive power switching groups.

[0015] Preferably, the method further includes:

[0016] Determine the voltage stiffness index according to the voltage modulus value after the installation position of each dynamic reactive power compensation device is connected to the grid-connected bus;

[0017] Select the grid-connected bus connected to the installation location where the voltage stiffness index is less than the preset stiffness threshold as the voltage clamping control bus of the dynamic reactive power compensation device.

[0018] Preferably, the calculation method of the voltage stiffness index is as follows:

[0019]

[0020] In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the i-th installation location, is the no-load voltage before the dynamic reactive power compensation device at the i-th installation location is connected to the grid connection point, is the voltage after the dynamic reactive power compensation device at the i-th installation location is connected to the grid connection point, is the impedance of the dynamic reactive power compensation device at the i-th installation location, is the Thevenin equivalent impedance of the dynamic reactive power compensation device at the i-th installation location, is the impedance angle of the dynamic reactive power compensation device at the i-th installation location, is the impedance angle of the sending-end power grid at the i-th installation location, is the short-circuit ratio representing the dynamic reactive power compensation device at the i-th installation location.

[0021] Preferably, the method further includes:

[0022] Determine the historical power peak and historical power valley according to the historical power data of the new energy power station in the sending-end power grid;

[0023] Perform summation processing on the operating power of each of the reference operating points according to the historical power peak and the historical power valley respectively, and determine the upper bound and lower bound of the power fluctuation of each of the reference operating points;

[0024] For each of the reference operating points, when the operating power of the reference operating point exceeds the upper bound or the lower bound of the power fluctuation within one action cycle of the dynamic reactive power compensation device, it is determined that a large-scale power fluctuation has occurred in the sending-end power grid.

[0025] Preferably, the step of determining the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located when a large-scale power fluctuation occurs in the sending-end power grid for each steady-state operation mode point includes:

[0026] For each steady-state operation mode point, when a large-scale power fluctuation occurs in the sending-end power grid, use the voltage clamping control bus where the dynamic reactive power compensation device is located as the PV bus;

[0027] Perform a power flow calculation on the dynamic reactive power compensation devices that are at the upper or lower bounds of the power fluctuation for the steady-state operation mode points according to the PV busbars, and determine the reactive power compensation amount of each dynamic reactive power compensation device.

[0028] Preferably, the step of determining the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts of the voltage clamping control busbars corresponding to multiple steady-state operation mode points includes:

[0029] Determine the maximum value of the reactive power compensation amounts according to the reactive power compensation amounts of the voltage clamping control busbars corresponding to multiple steady-state operation mode points;

[0030] Determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts and a preset stability margin coefficient.

[0031] In a second aspect, the present invention further provides a configuration optimization system for a dynamic reactive power compensation device of a new energy sending-end power grid, including:

[0032] A static reactive power determination module, configured to determine the switching situation of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operation point according to the operating power corresponding to multiple reference operation points of the sending-end power grid, where the reference operation point is a node in the sending-end power grid with an operating power below the rated power;

[0033] A reactive power compensation module, configured to determine, for each steady-state operation mode point, the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control busbar where it is located when the power of the sending-end power grid fluctuates greatly, where the steady-state operation mode point is the reference operation point for the switching situation of the static reactive power of the dynamic reactive power compensation device;

[0034] A dynamic reactive power determination module, configured to determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts of the voltage clamping control busbars corresponding to multiple steady-state operation mode points.

[0035] In a third aspect, the present invention further provides an electronic device, where the electronic device includes a memory and a processor, and a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the configuration optimization method for the dynamic reactive power compensation device of the new energy sending-end power grid as described in the first aspect.

[0036] In a fourth aspect, the present invention further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed, the steps of the configuration optimization method for the dynamic reactive power compensation device of the new energy sending-end power grid as described in the first aspect are implemented.

[0037] As can be seen from the above technical solutions, the present invention determines the switching situation of the static reactive power of the dynamic reactive power compensation device according to the operating power corresponding to multiple reference operating points of the sending-end power grid, determines the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located, and determines the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amount, so as to suppress large-scale fluctuations in the power of the sending-end power grid, thereby considering the impact of large-scale changes in the active power of the sending-end power grid accompanied by the strong randomness and volatility of new energy on reactive power, and realizing the coordinated control between dynamic reactive power and static reactive power considering large-scale fluctuations of new energy, improving the configuration accuracy of the dynamic reactive power compensation device, realizing the voltage stability brought by the fluctuation of the active power output accompanied by the strong randomness and volatility of new energy, and effectively controlling the voltage of the sending-end power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is an application environment diagram of a method for optimizing the configuration of a dynamic reactive power compensation device for a new energy sending-end power grid provided by an embodiment of the present invention;

[0039] Figure 2 It is a flowchart of a method for optimizing the configuration of a dynamic reactive power compensation device for a new energy sending-end power grid provided by an embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of a new energy sending-end power grid in the area to be planned provided by an embodiment of the present invention;

[0041] FIG. 4(a) is a frequency distribution histogram of the photovoltaic output power fluctuation of a typical new energy power station in the area to be planned provided by an embodiment of the present invention;

[0042] FIG. 4(b) is a frequency distribution histogram of the photovoltaic output power fluctuation at the 0-0.2 output level of a typical new energy power station in the area to be planned provided by an embodiment of the present invention;

[0043] FIG. 4(c) is a frequency distribution histogram of the photovoltaic output power fluctuation at the 0.2-0.4 output level of a typical new energy power station in the area to be planned provided by an embodiment of the present invention;

[0044] FIG. 4(d) is a frequency distribution histogram of the photovoltaic output power fluctuation at the 0.4-0.6 output level of a typical new energy power station in the area to be planned provided by an embodiment of the present invention;

[0045] FIG. 4(e) is a frequency distribution histogram of the photovoltaic output power fluctuation at the 0.6-0.8 output level of a typical new energy power station in the area to be planned provided by an embodiment of the present invention;

[0046] Figure 4(f) is a frequency distribution histogram of the photovoltaic output power fluctuation at the 0.8 - 1.0 output level of a typical new - energy power station in the area to be planned provided by the embodiment of the present invention;

[0047] Figure 5 It is a graph showing the change trend of the photovoltaic output power of a typical day for inspection provided by the embodiment of the present invention;

[0048] Figure 6 It is the voltage fluctuation condition of the 525 KV sub - station for inspection provided by the embodiment of the present invention;

[0049] Figure 7 It is a schematic structural diagram of a configuration optimization system for a dynamic reactive power compensation device in a new - energy sending - end power grid provided by the embodiment of the present invention;

[0050] Figure 8 It is a schematic structural diagram of an electronic device provided by the embodiment of the present invention. Detailed implementation manners

[0051] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0052] A configuration optimization method for a dynamic reactive power compensation device in a new - energy sending - end power grid provided by the embodiments of the present application can be applied to an application environment as Figure 1 shown. Among them, each node of the new - energy sending - end power grid communicates with the server 102 through a network. The new - energy sending - end power grid is transmitted by new - energy power stations, and the new - energy power stations are photovoltaic, wind power, energy storage, etc. The data storage system can store the data that the server 102 needs to process. The data storage system can be integrated on the server 102, or placed in the cloud or other network servers. The server 102 can be an independent physical server, or a server cluster or distributed system composed of multiple physical servers, or a cloud server providing cloud computing services.

[0053] As Figure 2 shown, a configuration optimization method for a dynamic reactive power compensation device in a new - energy sending - end power grid provided by the embodiments of the present application is described by taking the method applied to the Figure 1 server 102 as an example, and includes the following steps S1 to S3. Among them:

[0054] Step S1. Determine the switching status of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point according to the operating power corresponding to multiple reference operating points of the sending-end power grid, where the reference operating point is a node in the sending-end power grid with an operating power below the rated power.

[0055] Among them, the reference operating point can be any node in the sending-end power grid with an operating power below the rated power. When the operating power of the nodes in the sending-end power grid is below the rated power and the static reactive power has been input, the system operating state is such that the reactive power of the whole network is basically balanced. This state can be achieved by the AVC (Automatic Voltage Control) equipment of the power grid, simulating the steady-state situation where the static reactive power demand of the whole network during normal operation of the system is met by the dynamic reactive power compensation device.

[0056] Specifically, the process of determining the switching status of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point according to the operating power corresponding to multiple reference operating points of the sending-end power grid in Step S1 includes Steps S101 to S103. Among them:

[0057] Step S101. Normalize the operating power of the new energy power station with the rated power of the new energy power station, and equally divide the normalized operating power into multiple power per-unit value components.

[0058] Step S102. Determine multiple reference operating points of the sending-end power grid according to multiple power per-unit value components.

[0059] Among them, set multiple reference operating points of the sending-end power grid according to the new energy output level. Normalize the operating power of the new energy power station with the rated power P N of the new energy power station as the reference value, and divide it into N equal parts, which is used as the power set of multiple reference operating points of the new energy power station. The power set of multiple reference operating points is: , where , , , .

[0060] Step S103. Perform power flow calculations on the sending-end power grid according to the power per-unit values corresponding to multiple reference operating points, and obtain the switching status of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point. The switching status includes the static reactive power switching capacity and the number of static reactive power switching groups.

[0061] Among them, for each of the power sets of multiple reference operating points, the voltage, current, and power distribution of the system are respectively obtained through power flow calculations. According to the results of the power flow calculations, the optimal switching conditions of the dynamic reactive power compensation device at each reference operating point are determined, including the reactive power capacity and number of groups to be invested.

[0062] When determining the optimal switching conditions of the dynamic reactive power compensation device at each reference operating point, a multi-objective optimization problem can be used. Its optimization objectives include improving voltage stability, reducing network losses, and ensuring the safe and reliable operation of the system, and the multi-objective optimization problem is optimized to obtain the optimal switching conditions.

[0063] Step S2: For each steady-state operation mode point, when the power of the sending-end power grid fluctuates greatly, determine the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located. Among them, the steady-state operation mode point is the reference operating point for the switching conditions of the static reactive power of the dynamic reactive power compensation device.

[0064] Among them, the steady-state operation mode point is the reference operating point for the switching conditions of the static reactive power of the dynamic reactive power compensation device. In general examples, the number of steady-state operation mode points is the same as the number of reference operating points.

[0065] For the large-scale fluctuation of the power of the sending-end power grid, the upper and lower bounds of the new energy power station output at each reference operating point can be obtained through the analysis of the historical output data of the new energy power station, that is, the new energy power station can change to the maximum degree of output point within a short time (within one action cycle of AVC) based on historical data under the current power operation state.

[0066] Specifically, the process of judging whether the power of the sending-end power grid fluctuates greatly includes steps S21~S23. Among them:

[0067] Step S21: Determine the historical power peak and historical power valley according to the historical power data of the new energy power station in the sending-end power grid.

[0068] Among them, the historical period of the historical power data can be the previous year, the previous two years, etc. of the current period, and there is no limit here.

[0069] The maximum power and minimum power in the historical power data can be determined through the historical power data of the new energy power station as the historical power peak and historical power valley respectively.

[0070] Step S22: Perform summation processing on the operating power of each reference operating point according to the historical power peak and historical power valley respectively, and determine the upper bound and lower bound of the power fluctuation of each reference operating point.

[0071] Among them, the upper bound set and the lower bound set of the power fluctuations of multiple reference operating points are respectively defined as:

[0072]

[0073]

[0074] In the formula, and are respectively the upper bound set and the lower bound set of the power fluctuations. represents the historical power peak value of the nth reference operating point, represents the historical power valley value of the nth reference operating point.

[0075] Step S23: For each reference operating point, when the operating power of the reference operating point exceeds the upper bound or the lower bound of the power fluctuations within one action period of the dynamic reactive power compensation device, it is determined that large-scale fluctuations occur in the power of the sending-end power grid.

[0076] It can be understood that when the operating power of the reference operating point exceeds the upper bound or the lower bound of the power fluctuations within one action period of the dynamic reactive power compensation device, it indicates that large-scale fluctuations have occurred in the operating power of the reference operating point in a short period of time.

[0077] In some embodiments, the process of determining the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located in step S2 includes steps S201 to S202. Among them:

[0078] Step S201: For each steady-state operation mode point, when large-scale fluctuations occur in the power of the sending-end power grid, the voltage clamping control bus where the dynamic reactive power compensation device is located is taken as the PV bus.

[0079] Step S202: Perform power flow calculation on the dynamic reactive power compensation devices under the upper bound or the lower bound of the power fluctuations of the steady-state operation mode point according to the PV bus, and determine the reactive power compensation amount of each dynamic reactive power compensation device.

[0080] Among them, in the power flow data of different steady-state operation mode points, and taking the voltage clamping control bus where the dynamic reactive power compensation device is located as the PV bus and setting it as the PV bus, by means of power flow calculation, scan the magnitude of the reactive power generated by the dynamic reactive power compensation device when the new energy station fluctuates from each reference operating point to the upper and lower bounds of the new energy station output. Perform scanning calculations for different steady-state operation mode points respectively, and obtain the reactive power demand generated by the new energy output fluctuations under each steady-state operation point. The reactive power balance of the system under this basic operation mode is achieved by the control of the dynamic reactive power compensation device, and the dynamic reactive power is calculated on this basic operation mode.

[0081] Specifically, by means of power flow calculation, scan the set of the upper bounds of the power fluctuations and the set of the lower bounds of the power fluctuations of the new energy power station output, and the set composed of the reactive power magnitudes generated by m dynamic reactive power compensation devices at the j-th steady-state operation mode point:

[0082]

[0083]

[0084] In the formula, and are respectively the sets composed of the reactive power magnitudes generated by m dynamic reactive power compensation devices at the j-th steady-state operation mode point for the set of the upper bounds of the power fluctuations and the set of the lower bounds of the power fluctuations, and are respectively the reactive power magnitudes generated by m dynamic reactive power compensation devices at the j-th steady-state operation mode point.

[0085] Step S3: Determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts of the voltage clamping control buses corresponding to multiple steady-state operation mode points.

[0086] Specifically, in order to improve the system stability after reactive power compensation, in the embodiments of the present application, the maximum value is determined through the reactive power compensation amounts of the voltage clamping control buses corresponding to multiple steady-state operation mode points, and the dynamic reactive power input capacity of each dynamic reactive power compensation device is determined by using the maximum value of the reactive power compensation amounts.

[0087] Specifically, step S3 includes steps S301 to S302. Among them:

[0088] Step S301: Determine the maximum value of the reactive power compensation amounts according to the reactive power compensation amounts of the voltage clamping control buses corresponding to multiple steady-state operation mode points.

[0089] Step S302: Determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts and a preset stability margin coefficient.

[0090] Among them, the multiplication result of the maximum value of the reactive power compensation amounts and the preset stability margin coefficient is used as the dynamic reactive power input capacity of each dynamic reactive power compensation device.

[0091] Among them, the stability margin coefficient is a value greater than or equal to 1. As a preferred embodiment, the stability margin coefficient can be between 1.05 and 1.1.

[0092] It should be noted that the present invention determines the switching situation of the static reactive power of the dynamic reactive power compensation device according to the operating power corresponding to multiple reference operating points of the sending-end power grid, determines the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located, and determines the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amount, so as to suppress large-scale fluctuations in the power of the sending-end power grid, thereby considering the influence of large-scale changes in the active power of the sending-end power grid accompanied by the strong randomness and volatility of new energy on reactive power, and realizing the coordinated control between dynamic reactive power and static reactive power considering large-scale fluctuations of new energy, improving the configuration accuracy of the dynamic reactive power compensation device, realizing the voltage stability brought by the active power fluctuation accompanied by the strong randomness and volatility of new energy, and effectively controlling the voltage of the sending-end power grid.

[0093] In addition, the embodiment of the present application also selects the installation location of the additional dynamic reactive power compensation device based on the screening of the voltage stiffness index to ensure the accuracy and effectiveness of the installation of the dynamic reactive power compensation device.

[0094] In some embodiments, the method further includes steps S4 to S5. Among them:

[0095] Step S4: Determine the voltage stiffness index according to the voltage modulus value after the dynamic reactive power compensation device at each installation location is connected to the grid-connected bus.

[0096] Among them, the installation location of the dynamic reactive power compensation device is the initial installation location, generally selected as the grid connection point of each new energy power station. For a photovoltaic power station with a booster station, it is the high-voltage side bus or node of the booster station; for a photovoltaic power station without a booster station, it is the output aggregation point of the photovoltaic power station.

[0097] For the calculation method of the voltage stiffness index:

[0098]

[0099] In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the i-th installation location, is the no-load voltage before the dynamic reactive power compensation device at the i-th installation location is connected to the grid connection point, is the voltage after the dynamic reactive power compensation device at the i-th installation location is connected to the grid connection point, is the impedance of the dynamic reactive power compensation device at the i-th installation location, is the Thevenin equivalent impedance of the dynamic reactive power compensation device at the i-th installation location, is the impedance angle of the dynamic reactive power compensation device at the i-th installation location, is the impedance angle of the sending-end power grid at the i-th installation location, It represents the short-circuit ratio of the dynamic reactive power compensation device at the i-th installation location.

[0100] Step S5: Screen out the grid-connected busbars connected to the installation locations where the voltage stiffness index is less than the preset stiffness threshold as the voltage clamping control busbars of the dynamic reactive power compensation device.

[0101] Among them, the voltage clamping control busbar is the grid-connected busbar at the installation location of the dynamic reactive power compensation device.

[0102] It should be noted that the voltage stiffness index can be used to measure the ability of the new energy grid-connected equipment to maintain the stability of the grid voltage after being connected to the grid. Therefore, this method can effectively screen out the most effective installation locations of the dynamic reactive power compensation device, ensure the accuracy and effectiveness of the installation of the dynamic reactive power compensation device, and effectively address the problem of insufficient voltage support capacity of large-scale new energy bases with long-distance transmission under multiple voltage levels, and improve the voltage support intensity of new energy power stations at both far and near ends.

[0103] The following is an example calculation proposed in combination with the configuration optimization method of the dynamic reactive power compensation device for a new energy sending-end power grid provided in this application embodiment.

[0104] In this example calculation, the structure of the new energy sending-end power grid in the area to be planned is as Figure 3 shown. After several new energy power stations converge to the 220 kV converging station, they are further stepped up and converged to the 525 kV converging station, and finally sent out through a flexible DC converter.

[0105] Obtain the historical output data of the new energy power stations in the new energy sending-end power grid in the area to be planned. According to a certain photovoltaic power station, 8765 hours in a year are taken, and 12 five-minute intervals per hour, a total of 105,180 data points are used for photovoltaic output data analysis. The frequency distribution histogram of the photovoltaic output fluctuation is made as shown in Figure 4(a). Taking the rated power of the new energy power station as the reference value, the power of the new energy power station is normalized and divided into 5 equal parts to obtain the set P0 = {0, 0.2, 0.4, 0.6, 0.8, 1} of the reference operating power points of the new energy power station.

[0106] According to the historical output data of photovoltaic power, analyze the output fluctuations at different output interval levels. As can be seen from Figure 4(b), when the photovoltaic output is between 0 and 0.2, the fluctuation range is 0 to 0.8. As can be seen from Figure 4(c), when the photovoltaic output is between 0.2 and 0.4, the fluctuation range is -0.2 to 0.8. As can be seen from Figure 4(d), when the photovoltaic output is between 0.4 and 0.6, the fluctuation range is -0.4 to 0.6. As can be seen from Figure 4(e), when the photovoltaic output is between 0.6 and 0.8, the fluctuation range is -0.6 to 0.4. As can be seen from Figure 4(f), when the photovoltaic output is between 0.4 and 0.6, the fluctuation range is -0.6 to 0.2. Through the analysis of the historical output data of the new energy power station, the upper bound set P 0+ ={0.8, 1.0, 1.0, 1.0, 1.0, 1.0} of the output of the new energy power station at each reference operating point and the lower bound set P 0- ={0, 0, 0, 0, 0.2, 0.4} are obtained.

[0107] Based on several reference operating points of the selected sending-end power grid, calculate the switching situation of static reactive power at different reference operating points, and then obtain different steady-state operating mode points of the sending-end power grid as shown in Table 1.

[0108] Table 1 Different steady-state operating mode points

[0109]

[0110] Taking the 220 kV grid-connected bus of the new energy power station as the preferred installation location of the dynamic reactive power compensation device, calculate the voltage stiffness index of each preferred installation location. Set the threshold of the voltage stiffness index to 0.95, and the bus with the voltage stiffness calculation result less than 0.95 is set as the installation location of the dynamic reactive power compensation device.

[0111] In the power flow data of different initial steady-state operating mode points, and set the voltage clamping control bus as the PV bus, scan the upper bound set of the output of the new energy power station through the power flow calculation and the lower bound set to form a set of the reactive power magnitudes generated by the m dynamic reactive power compensation devices at the jth steady-state operating mode point.

[0112] Take the maximum value of the dynamic reactive power output magnitudes of each dynamic reactive power compensation device calculated at different steady-state operating mode points, and multiply it by the stability margin coefficient 1.1 to obtain the dynamic reactive power capacity configuration of the voltage clamping control bus where each dynamic reactive power compensation device is located as shown in Table 2.

[0113] Table 2 Dynamic reactive power configuration of the voltage clamping control bus where each dynamic reactive power compensation device is located

[0114]

[0115] Select 24 data points in 2 hours with large fluctuations in PV output in a certain year as an example to verify the voltage stability of the system when adopting the above dynamic reactive power capacity quota. The trend chart of PV output changing with time is as Figure 5 shown Figure 5 which shows the PV output from 10:15:00 to 12:15:00 on a certain day.

[0116] Considering that the static reactive power is switched every 15 minutes, verify whether the dynamic reactive power configuration scheme of 220 kV meets the requirements. As shown in Table 3, during the whole process, the maximum dynamic reactive power output of the 220 kV clamped bus is always less than the dynamic reactive power configuration capacity of each clamped bus, and all dynamic reactive power compensation devices do not exceed the limit.

[0117] Table 3 Maximum dynamic reactive power output of 220 kV clamped bus

[0118]

[0119] During the studied 2 hours, the voltage fluctuations of each 525 kV collection station are as Figure 6 shown. It can be seen from Figure 6 that the voltage of each collection station bus is between 0.997 p.u. and 1.012 p.u., and the system voltage is within the safe range, which proves the effectiveness of the method proposed in this application.

[0120] Based on the same inventive concept, the embodiment of this application also provides a configuration optimization system for a dynamic reactive power compensation device of a new energy sending-end power grid for implementing the configuration optimization method of the dynamic reactive power compensation device of the above-mentioned new energy sending-end power grid.

[0121] The implementation solution provided by this system to solve the problem is similar to the implementation solution described in the above method. Therefore, the specific limitations in one or more of the following configuration optimization system embodiments of the dynamic reactive power compensation device of the new energy sending-end power grid can refer to the limitations on the configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid in the above text, and will not be elaborated here.

[0122] As Figure 7 shown, the embodiment of this application also provides a configuration optimization system for a dynamic reactive power compensation device of a new energy sending-end power grid, including:

[0123] The static reactive power determination module 100 is used to determine the switching conditions of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point according to the operating power corresponding to multiple reference operating points of the sending-end power grid, where the reference operating point is a node in the sending-end power grid with an operating power below the rated power;

[0124] The reactive power compensation module 200 is used to determine the reactive power compensation amount of the dynamic reactive power compensation device for its voltage clamping control bus when the power of the sending-end power grid fluctuates greatly for each steady-state operation mode point, where the steady-state operation mode point is the reference operating point for the switching conditions of the static reactive power of the dynamic reactive power compensation device;

[0125] The dynamic reactive power determination module 300 is used to determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amounts of the voltage clamping control buses corresponding to multiple steady-state operation mode points.

[0126] In some embodiments, the static reactive power determination module 100 is further used to normalize the operating power of the new energy power station with the rated power of the new energy power station, and equally divide the normalized operating power into multiple power per-unit value components;

[0127] Determine multiple reference operating points of the sending-end power grid according to multiple power per-unit value components;

[0128] Perform power flow calculations on the sending-end power grid according to the power per-unit values corresponding to multiple reference operating points, and obtain the switching conditions of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point. The switching conditions include the static reactive power switching capacity and the static reactive power switching number of groups.

[0129] In some embodiments, the system further includes: a site selection module, which is used to determine the voltage stiffness index according to the voltage modulus value after the installation position of each dynamic reactive power compensation device is connected to the grid-connected bus; and screen out the grid-connected bus connected to the installation position with a voltage stiffness index less than the preset stiffness threshold as the voltage clamping control bus of the dynamic reactive power compensation device.

[0130] Among them, the calculation method of the voltage stiffness index is:

[0131]

[0132] In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the i-th installation position, is the no-load voltage before the dynamic reactive power compensation device at the i-th installation position is connected to the grid connection point, is the voltage after the dynamic reactive power compensation device at the i-th installation position is connected to the grid connection point, is the impedance of the dynamic reactive power compensation device at the i-th installation position, is the Thevenin equivalent impedance of the dynamic reactive power compensation device at the i-th installation location, is the impedance angle of the dynamic reactive power compensation device at the i-th installation location, is the impedance angle of the sending-end power grid at the i-th installation location, represents the short-circuit ratio of the dynamic reactive power compensation device at the i-th installation location.

[0133] In some embodiments, the system further includes: a fluctuation judgment module, configured to determine a historical power peak and a historical power valley according to historical power data of a new energy power station in the sending-end power grid; perform summation processing on the operating power of each reference operating point according to the historical power peak and the historical power valley respectively, to determine an upper power fluctuation bound and a lower power fluctuation bound of each reference operating point; for each reference operating point, when the operating power of the reference operating point exceeds the upper power fluctuation bound or the lower power fluctuation bound within an action period of the dynamic reactive power compensation device, it is determined that a large-scale power fluctuation occurs in the sending-end power grid.

[0134] In some embodiments, the reactive power compensation module 200 is configured to, for each steady-state operation mode point, when a large-scale power fluctuation occurs in the sending-end power grid, use the voltage clamping control bus where the dynamic reactive power compensation device is located as the PV bus; perform power flow calculation on the dynamic reactive power compensation device at the upper or lower power fluctuation bound of the steady-state operation mode point according to the PV bus, to determine the reactive power compensation amount of each dynamic reactive power compensation device.

[0135] In some embodiments, the dynamic reactive power determination module 300 is configured to determine the maximum value of the reactive power compensation amount according to the reactive power compensation amounts of the voltage clamping control buses respectively corresponding to multiple steady-state operation mode points; determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum value of the reactive power compensation amount and a preset stability margin coefficient.

[0136] As Figure 8 shown, the embodiment of the present application further provides an electronic device. The electronic device 10 includes a memory 20 and a processor 30. A computer program is stored in the memory 20. When the computer program is executed by the processor 30, the processor 30 is caused to execute the steps of the configuration optimization method of the dynamic reactive power compensation device for the new energy sending-end power grid in any of the above embodiments.

[0137] The embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed, the steps of the configuration optimization method of the dynamic reactive power compensation device for the new energy sending-end power grid in any of the above embodiments are implemented.

[0138] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, electronic devices, and computer storage media described above can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0139] It should be noted that the terms "first", "second", etc. in the specification, claims, and drawings of the present invention are used to distinguish similar objects and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order different from those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0140] In several embodiments provided by the present invention, it can be understood that each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code includes one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order from that marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, depending on the functions involved.

[0141] In several embodiments provided by the present invention, it should be understood that the disclosed systems, electronic devices, computer storage media, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Another point is that the displayed or discussed couplings, direct couplings, or communication connections to each other may be through some interfaces, and the indirect couplings or communication connections of devices or units may be in electrical, mechanical, or other forms.

[0142] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0143] In addition, in each embodiment of the present invention, each functional unit can be integrated into a processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0144] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods in each embodiment of the present invention. The aforementioned storage medium includes: USB flash drives, mobile hard disks, read-only memories (English full name: Read-Only Memory, English abbreviation: ROM), random access memories (English full name: Random Access Memory, English abbreviation: RAM), magnetic disks, or optical discs and other various media that can store program codes.

[0145] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A configuration optimization method for a dynamic reactive power compensation device of a new energy sending-end power grid, characterized in that: include: Determining the switching status of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point according to the operating power corresponding to each of the plurality of reference operating points of the sending-end power grid, wherein the reference operating point is a node in the sending-end power grid where the operating power is below the rated power, including: The operating power of the new energy station is normalized by the rated power of the new energy station, and the normalized operating power is equally divided into a plurality of power normalized value components; Determining a plurality of reference operating points of the sending-end power grid according to a plurality of the per-unit power value components; Performing power flow calculation on the sending-end power grid according to the power per unit values ​​corresponding to the plurality of reference operating points, to obtain the static reactive switching condition of the dynamic reactive compensation device corresponding to each reference operating point, wherein the switching condition includes the static reactive switching capacity and the number of static reactive switching groups; For each steady-state operation mode point, when the power of the sending-end power grid fluctuates over a large range, the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where the dynamic reactive power compensation device is located is determined, wherein the steady-state operation mode point is a reference operation point of the static reactive power switching condition of the dynamic reactive power compensation device; The dynamic reactive input capacity of each of the dynamic reactive compensation devices is determined according to the maximum value of the reactive compensation amount of the voltage clamp control bus corresponding to the plurality of steady-state operation mode points.

2. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 1 is characterized in that: Also includes: Determine the voltage stiffness index according to the voltage modulus value after each installation position of the dynamic reactive power compensation device is connected to the grid-connected bus; The grid-connected busbar connected to the installation location where the voltage stiffness index is less than a preset stiffness threshold is screened out as the voltage clamping control busbar of the dynamic reactive power compensation device.

3. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 2 is characterized in that: The calculation method of the voltage stiffness index is: In the formula, K vtgi is the voltage stiffness index of the dynamic reactive power compensation device at the ith installation location, U sys0i is the no-load voltage before the dynamic reactive power compensation device at the ith installation location is connected to the grid, U sysi is the voltage after the dynamic reactive power compensation device at the ith installation location is connected to the grid, Z devicei is the impedance of the dynamic reactive power compensation device at the ith installation location, Z thi is the Thevenin equivalent impedance of the dynamic reactive power compensation device at the ith installation location, is the impedance angle of the dynamic reactive power compensation device at the ith installation location, is the impedance angle of the sending-end grid at the ith installation location, λ SCRi is the short-circuit ratio of the dynamic reactive power compensation device at the ith installation location.

4. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 1 is characterized in that: Also includes: Determine the historical power peak value and the historical power valley value according to the historical power data of the new energy station of the sending-end power grid; According to the historical power peak value and the historical power valley value, the operating power of each of the reference operating points is summed up to determine the power fluctuation upper bound and the power fluctuation lower bound of each of the reference operating points; For each of the reference operating points, when the operating power of the reference operating point exceeds the power fluctuation upper limit or the power fluctuation lower limit within an action cycle of the dynamic reactive power compensation device, it is determined that the power of the sending-end power grid fluctuates over a large range.

5. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 4 is characterized in that: The step of determining the reactive power compensation amount of the voltage clamping control busbar of the dynamic reactive power compensation device for each steady-state operation mode point when the power of the sending-end power grid fluctuates widely comprises: For each steady-state operation mode point, when the power of the sending-end power grid fluctuates widely, the voltage clamping control bus where the dynamic reactive power compensation device is located is used as the PV bus; The reactive compensation amount of each of the dynamic reactive compensation devices is determined by performing flow calculation on the dynamic reactive compensation devices whose steady-state operation mode point is below the upper limit of the power fluctuation or the lower limit of the power fluctuation according to the PV bus.

6. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 1 or 5 is characterized in that: The step of determining the dynamic reactive input capacity of each of the dynamic reactive compensation devices according to the maximum value of the reactive compensation amount of the voltage clamp control bus corresponding to the plurality of steady-state operation mode points respectively comprises: Determine the maximum value of the reactive power compensation amount according to the reactive power compensation amounts of the voltage clamp control busbars respectively corresponding to the plurality of steady-state operation mode points; The dynamic reactive input capacity of each of the dynamic reactive compensation devices is determined according to the maximum value of the reactive compensation amount and a preset stability margin coefficient.

7. A configuration optimization system for a dynamic reactive power compensation device of a new energy sending-end power grid, characterized in that: include: A static reactive power determination module, used to determine the static reactive power switching of the dynamic reactive power compensation device corresponding to each reference operating point according to the operating power corresponding to each of the multiple reference operating points of the sending-end power grid, wherein the reference operating point is a node in the sending-end power grid whose operating power is below the rated power; Determining the switching status of the static reactive power of the dynamic reactive power compensation device corresponding to each reference operating point according to the operating power corresponding to each of the reference operating points of the sending-end power grid, including: The operating power of the new energy station is normalized by the rated power of the new energy station, and the normalized operating power is equally divided into a plurality of power normalized value components; Determining a plurality of reference operating points of the sending-end power grid according to a plurality of the per-unit power value components; Performing power flow calculation on the sending-end power grid according to the power per unit values ​​corresponding to the plurality of reference operating points, to obtain the static reactive switching condition of the dynamic reactive compensation device corresponding to each reference operating point, wherein the switching condition includes the static reactive switching capacity and the number of static reactive switching groups; A reactive power compensation module is used to determine, for each steady-state operation mode point, when the power of the sending-end power grid fluctuates widely, the reactive power compensation amount of the dynamic reactive power compensation device for the voltage clamping control bus where it is located, wherein the steady-state operation mode point is a reference operation point of the static reactive power switching condition of the dynamic reactive power compensation device; The dynamic reactive power determination module is used to determine the dynamic reactive power input capacity of each of the dynamic reactive power compensation devices according to the maximum value of the reactive power compensation amount of the voltage clamp control bus corresponding to the plurality of steady-state operation mode points.

8. An electronic device, characterized in that: The electronic device includes a memory and a processor, wherein a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid as described in any one of claims 1 to 6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the steps of the method for optimizing the configuration of the dynamic reactive power compensation device of the new energy sending-end power grid are implemented.

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