Configuration optimization method and system for dynamic reactive power compensation device of new energy sending end power grid

Abstract

The 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 of a new energy sending-end power grid, and the method comprises the steps: determining the static reactive power switching condition of the dynamic reactive power compensation device through the operation power corresponding to a plurality of reference operation points of the sending-end power grid; and the reactive power compensation amount of the dynamic reactive power compensation device to the voltage clamp control bus where the dynamic reactive power compensation device is located is determined, and the dynamic reactive power input capacity of each dynamic reactive power compensation device is determined according to the maximum value of the reactive power compensation amount, so that the large-range fluctuation of the power of the sending-end power grid is inhibited. Coordination control between dynamic reactive power and static reactive power considering large-range fluctuation of new energy is realized, configuration accuracy of a dynamic reactive power compensation device is improved, and voltage stability brought by active output fluctuation accompanied by strong randomness and fluctuation of the new energy and effective control of sending-end power grid voltage are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of power grid equipment, and in particular to a configuration optimization method and system for a dynamic reactive power compensation device of 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 sources require flexible DC transmission systems for long-distance, large-scale centralized transmission. In the early stage of the operation of the Shagohuang large-scale new energy transmission base, the sending-end power grid usually has no conventional power support, and the grid characteristics are basically dominated by power electronic equipment. The voltage of the sending-end grid is completely determined by the flexible DC converter station. Compared with the traditional synchronous power system, 100% of the power electronic equipment dominates the power system. The active and reactive imbalances in the AC power grid will be uniformly reflected as system voltage changes (voltage collapse, voltage fluctuations exceeding the standard, overvoltage, etc.), and voltage distribution and disturbance response become the core issues of the system operation characteristics.

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

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

[0005] The configuration of dynamic reactive power compensation devices is the main key technology to improve the voltage support capacity of the wide-area renewable energy sending-end power grid and solve the voltage stability problem caused by the active power output fluctuations of renewable energy. However, the configuration accuracy of the current dynamic reactive power compensation devices is relatively poor, resulting in poor voltage stability caused by the active power output fluctuations accompanied by the strong randomness and volatility of renewable energy, making it difficult to achieve effective control of the sending-end power grid voltage. Summary of the invention

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

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

[0008] 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 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 where the operating power is below the rated power;

[0009] 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;

[0010] 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.

[0011] Preferably, the step of determining the static reactive switching status of the dynamic reactive compensation device corresponding to each reference operating point according to the operating powers respectively corresponding to the multiple reference operating points of the sending-end power grid includes:

[0012] 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;

[0013] Determining a plurality of reference operating points of the sending-end power grid according to a plurality of the per-unit power value components;

[0014] The power flow of the sending-end power grid is calculated according to the power per unit values ​​corresponding to the multiple reference operating points, so as to obtain the static reactive switching status of the dynamic reactive compensation device corresponding to each reference operating point, wherein the switching status includes the static reactive switching capacity and the number of static reactive switching groups.

[0015] Preferably, the method further comprises:

[0016] 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;

[0017] The grid-connected busbar connected to the installation location whose 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.

[0018] Preferably, the voltage stiffness index is calculated as follows:

[0019]

[0020] In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the ith installation location, is the no-load voltage before the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the voltage after the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the impedance of the dynamic reactive power compensation device at the ith installation location, 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 power grid at the ith installation location, is the short-circuit ratio of the dynamic reactive power compensation device at the ith installation location.

[0021] Preferably, the method further comprises:

[0022] 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;

[0023] 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;

[0024] 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.

[0025] Preferably, for each steady-state operation mode point, when the power of the sending-end power grid fluctuates over a large range, 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 comprises:

[0026] 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;

[0027] 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.

[0028] Preferably, 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:

[0029] 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;

[0030] 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.

[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, comprising:

[0032] 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;

[0033] 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;

[0034] 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.

[0035] In a third aspect, the present invention further provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and 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 the first aspect.

[0036] In a fourth aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the steps of the method for optimizing the configuration of the dynamic reactive power compensation device of the new energy sending-end power grid as described in the first aspect.

[0037] It can be seen from the above technical scheme that the present invention determines the switching status of the static reactive power of the dynamic reactive compensation device through the operating power corresponding to multiple reference operating points of the sending-end power grid, and determines the reactive compensation amount of the voltage clamping control busbar of the dynamic reactive compensation device to which it is located, and determines the dynamic reactive input capacity of each dynamic reactive compensation device according to the maximum value of the reactive compensation amount, thereby suppressing the large-scale fluctuation of the power of the sending-end power grid, thereby taking into account the influence of the large-scale change of the active power of the sending-end power grid accompanied by the strong randomness and volatility of new energy on the reactive power, and realizing the coordinated control between the dynamic reactive power considering the large-scale fluctuation of new energy and the static reactive power, improving the configuration accuracy of the dynamic reactive compensation device, realizing the voltage stability brought by the active power output fluctuation accompanied by the strong randomness and volatility of new energy, and the effective control of the voltage of the sending-end power grid. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0040] Figure 3 A schematic diagram of a new energy transmission-end power grid in a region to be planned provided by an embodiment of the present invention;

[0041] FIG4 (a) is a frequency distribution histogram of photovoltaic output fluctuations of a typical new energy station in a planned area provided by an embodiment of the present invention;

[0042] FIG4 (b) is a frequency distribution histogram of photovoltaic output fluctuations at an output level of 0-0.2 of a typical new energy station in a planned area provided by an embodiment of the present invention;

[0043] FIG4 (c) is a frequency distribution histogram of photovoltaic output fluctuations at an output level of 0.2-0.4 of a typical new energy station in a planned area provided by an embodiment of the present invention;

[0044] FIG4 (d) is a frequency distribution histogram of photovoltaic output fluctuations at an output level of 0.4-0.6 of a typical new energy station in a planned area provided by an embodiment of the present invention;

[0045] FIG4 (e) is a frequency distribution histogram of photovoltaic output fluctuations at an output level of 0.6-0.8 of a typical new energy station in a planned area provided by an embodiment of the present invention;

[0046] FIG4( f ) is a frequency distribution histogram of photovoltaic output fluctuations at an output level of 0.8-1.0 of a typical new energy station in a planned area provided by an embodiment of the present invention;

[0047] Figure 5 A graph showing a trend of photovoltaic output changes on a typical day for verification provided by an embodiment of the present invention;

[0048] Figure 6 The voltage fluctuation of a 525 KV collection station on a typical day for inspection provided by an embodiment of the present invention;

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

[0050] Figure 8 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] The configuration optimization method of a dynamic reactive power compensation device of a new energy sending-end power grid provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown. Among them, each node of the new energy sending-end power grid communicates with the server 102 through the network. The new energy sending-end power grid is transmitted by the new energy station, and the new energy station is photovoltaic, wind power and energy storage. 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 it can be placed on the cloud or other network servers. The server 102 can be an independent physical server, or it can be a server cluster or distributed system composed of multiple physical servers, or it can be a cloud server that provides cloud computing services.

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

[0054] Step S1, determining the static reactive switching status of the dynamic reactive compensation device corresponding to each reference operating point according to the operating powers corresponding to 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.

[0055] Among them, the reference operating point can be any node in the sending-end power grid whose operating power is below the rated power. The operating power of the node of the sending-end power grid is below the rated power. After the static reactive power has been put into use, the system operating state of the whole network is basically balanced. This state can be achieved by the AVC (Automatic Voltage Control) equipment of the power grid, which simulates the steady-state situation in which the static reactive power demand of the whole network is met by the dynamic reactive power compensation device when the system is operating normally.

[0056] Specifically, the process of determining the static reactive switching status of the dynamic reactive 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 in step S1 includes steps S101 to S103. Among them:

[0057] Step S101: normalize the operating power of the new energy station with the rated power of the new energy station, and divide the normalized operating power into a plurality of power normalized value components.

[0058] Step S102: determining a plurality of reference operating points of the sending-end power grid according to a plurality of per-unit power value components.

[0059] Among them, multiple benchmark operation points of the sending-end power grid are set according to the output level of renewable energy, with the rated power P of the renewable energy station as the N The operating power of the new energy station is normalized as a benchmark value and divided into N equal parts to serve as the power set of multiple benchmark operating points of the new energy station. The power set of multiple benchmark operating points is: , where , , , .

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

[0061] Among them, for each benchmark operating point in the power set of multiple benchmark operating points, the voltage, current and power distribution of the system are obtained respectively by means of power flow calculation. According to the results of power flow calculation, the optimal switching condition of the dynamic reactive compensation device at each benchmark operating point is determined, including the reactive capacity and number of groups required to be invested.

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

[0063] Step S2, for each steady-state operation mode point, when the power of the sending-end power grid fluctuates over a large range, determine the reactive power compensation amount of the voltage clamping control busbar where the dynamic reactive power compensation device is located, wherein the steady-state operation mode point is a reference operation point for the static reactive power switching condition of the dynamic reactive power compensation device.

[0064] The steady-state operation mode point is a reference operation point for the switching condition of the static reactive power of the dynamic reactive power compensation device. In a general example, the number of the steady-state operation mode point is consistent with that of the reference operation point.

[0065] When the power of the sending-end power grid fluctuates widely, the upper and lower bounds of the output of the new energy station under each benchmark operating point can be obtained by analyzing the historical output data of the new energy station, that is, the maximum output point that the new energy station can reach in a short time (within one AVC action cycle) based on historical data under the current power operating state.

[0066] Specifically, the process of determining whether the power of the sending-end power grid fluctuates in a large range includes steps S21 to S23.

[0067] Step S21: 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.

[0068] The historical period of historical power data may be one year or two years before the current period, etc., and is not limited thereto.

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

[0070] Step S22: summing up the operating power of each reference operating point according to the historical power peak value and the historical power valley value, and determining the power fluctuation upper limit and the power fluctuation lower limit of each reference operating point.

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

[0072]

[0073]

[0074] In the formula, , are the power fluctuation upper bound set and the power fluctuation lower bound set respectively, represents the historical power peak value of the nth reference operating point, Indicates 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 limit of power fluctuation or the lower limit of power fluctuation within one action cycle of the dynamic reactive power compensation device, it is determined that the power of the sending-end power grid fluctuates widely.

[0076] It is understandable that when the operating power of the reference operating point exceeds the upper limit of power fluctuation or the lower limit of power fluctuation within one action cycle of the dynamic reactive power compensation device, it means that the operating power of the reference operating point has fluctuated widely in a short period of time.

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

[0078] Step S201: 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.

[0079] Step S202: Perform power flow calculation on the dynamic reactive compensation devices whose steady-state operation mode points are below the upper limit of power fluctuation or the lower limit of power fluctuation according to the PV busbar, and determine the reactive compensation amount of each dynamic reactive compensation device.

[0080] Among them, in the flow data of different steady-state operation mode points, the voltage clamp control bus where the dynamic reactive power compensation device is located is set as the PV bus, and the size of the reactive power generated by the dynamic reactive power compensation device is scanned by the flow calculation method when the new energy station fluctuates from each benchmark operation point to the upper and lower limits of the output of the new energy station. Scanning calculations are performed for different steady-state operation mode points respectively to obtain the reactive power demand generated by the fluctuation of new energy output at each steady-state operation point. The reactive 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, the power fluctuation upper bound set and the power fluctuation lower bound set of the output of the new energy station are scanned by the power flow calculation method, and the set of reactive power generated by the m dynamic reactive compensation devices at the jth steady-state operation mode point is:

[0082]

[0083]

[0084] In the formula, , The power fluctuation upper bound set and the power fluctuation lower bound set are respectively the sets of reactive power generated by the m dynamic reactive compensation devices at the jth steady-state operation mode point, , They are respectively the reactive power generated by the m dynamic reactive power compensation devices at the jth steady-state operation point.

[0085] Step S3, determining the dynamic reactive input capacity of each dynamic reactive compensation device according to the maximum value of the reactive compensation amount of the voltage clamp control bus corresponding to a plurality of steady-state operation mode points.

[0086] Specifically, in order to improve the system stability after reactive power compensation, in an embodiment of the present application, the maximum value of the reactive power compensation amount of the busbar corresponding to the voltage clamp control points of multiple steady-state operating modes is determined, and the dynamic reactive power input capacity of each dynamic reactive power compensation device is determined using the maximum value of the reactive power compensation amount.

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

[0088] Step S301, determining a maximum reactive power compensation amount according to reactive power compensation amounts of voltage clamp control buses corresponding to a plurality of steady-state operation mode points.

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

[0090] The multiplication result of the maximum value of the reactive compensation amount and the preset stability margin coefficient is used as the dynamic reactive input capacity of each dynamic reactive compensation device.

[0091] The stability margin coefficient is a value greater than 1. As a preferred embodiment, the stability margin coefficient may be between 1.05 and 1.1.

[0092] It should be noted that the present invention determines the switching status of the static reactive power of the dynamic reactive compensation device through the operating power corresponding to multiple reference operating points of the sending-end power grid, and determines the reactive compensation amount of the dynamic reactive compensation device for the voltage clamping control bus to which it is located, and determines the dynamic reactive input capacity of each dynamic reactive compensation device according to the maximum value of the reactive compensation amount, thereby suppressing the large-scale fluctuation of the power of the sending-end power grid, thereby taking into account the impact of the large-scale change of the active power of the sending-end power grid accompanied by the strong randomness and volatility of new energy on the reactive power, and realizing the coordinated control between the dynamic reactive power considering the large-scale fluctuation of new energy and the static reactive power, improving the configuration accuracy of the dynamic reactive compensation device, and realizing the voltage stability brought about by the active power output fluctuation accompanied by the strong randomness and volatility of new energy, as well as the effective control of 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.

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

[0096] Among them, the installation location of the dynamic reactive power compensation device is the initial installation location, which is generally selected as the grid connection point of each new energy 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] The calculation method for the voltage stiffness index is:

[0098]

[0099] In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the ith installation location, is the no-load voltage before the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the voltage after the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the impedance of the dynamic reactive power compensation device at the ith installation location, 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 power grid at the ith installation location, is the short-circuit ratio of the dynamic reactive power compensation device at the ith installation location.

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

[0101] The voltage clamping control bus is the access bus 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 grid to maintain stable voltage after the new energy grid-connected equipment is connected to the grid. Therefore, this method can effectively screen out the most effective installation location of the dynamic reactive power compensation device, ensure the accuracy and effectiveness of the installation of the dynamic reactive power compensation device, and effectively deal with the problem of insufficient voltage support capacity of large-scale new energy bases for long-distance transmission under multiple voltage levels, thereby improving the voltage support strength of remote new energy stations.

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

[0104] In this example, the structure of the new energy transmission grid in the planned area is as follows: Figure 3 As shown in the figure, after several new energy stations are gathered at the 220kV collection station, they are further boosted and gathered at the 525kV collection station, and finally transmitted through flexible DC conversion.

[0105] The historical output data of the new energy stations of the new energy sending-end power grid in the planned area are obtained. According to a certain photovoltaic station, 105,180 data points are taken for 8,765 hours a year and 12 five-minute data points per hour for photovoltaic output data analysis. The frequency distribution histogram of photovoltaic output fluctuation is shown in Figure 4 (a). Taking the rated power of the new energy station as the reference value, the power of the new energy station is normalized and divided into 5 equal parts to obtain the set of benchmark operating power points P of the new energy station. 0 ={0,0.2,0.4,0.6,0.8,1}

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

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

[0108] Table 1 Different steady-state operation points

[0109]

[0110] The 220 kV grid-connected busbar of the new energy station is used as the preferred placement of the dynamic reactive power compensation device, and the voltage stiffness index of each preferred installation location is calculated respectively. The threshold of the voltage stiffness index is set to 0.95, and the busbar with a 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 at different initial steady-state operation points, the voltage clamp control bus is set as the PV bus, and the upper limit set of the output of the new energy station is scanned by power flow calculation. With the lower bound set The set consisting of the reactive power generated by m dynamic reactive compensation devices at the jth steady-state operating point.

[0112] The dynamic reactive power output of each dynamic reactive power compensation device calculated under different steady-state operation modes is taken as the maximum value, and multiplied by the stability margin coefficient 1.1, and the dynamic reactive power capacity configuration of the voltage clamping control bus where each dynamic reactive power compensation device is located is obtained as shown in Table 2.

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

[0114]

[0115] A total of 24 data points were selected for two hours in a year when the photovoltaic output fluctuated greatly as an example to verify the voltage stability of the system when the above dynamic reactive power capacity quota was adopted. Figure 5 As shown, Figure 5 The photovoltaic output situation from 10:15:00 to 12:15:00 on a certain day is shown.

[0116] Considering that the static reactive power is switched every 15 minutes, it is verified whether the 220kV dynamic reactive power configuration scheme 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 are within the limit.

[0117] Table 3 Maximum dynamic reactive power output of 220 KV clamped busbar

[0118]

[0119] During the 2 hours studied, the voltage fluctuations at each 525 KV collection station are as follows: Figure 6 As shown. Figure 6 It can be seen that the voltage of the busbars of each collection station is between 0.997 pu and 1.012 pu, and the system voltage is within a safe range, which proves the effectiveness of the method proposed in this application.

[0120] Based on the same inventive concept, an embodiment of the present 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 a dynamic reactive power compensation device of a new energy sending-end power grid involved above.

[0121] The implementation solution to the problem provided by the system is similar to the implementation solution recorded in the above method. Therefore, the specific limitations in the configuration optimization system embodiments of one or more dynamic reactive compensation devices of a new energy sending-end power grid provided below can be referred to the limitations of the configuration optimization method for a dynamic reactive compensation device of a new energy sending-end power grid mentioned above, and will not be repeated here.

[0122] like Figure 7 As shown, the embodiment of the present 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 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 where the operating power is below the rated power;

[0124] The reactive power compensation module 200 is used to determine the reactive power compensation amount of the voltage clamp 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, 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;

[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 amount of the voltage clamp control bus 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 station with the rated power of the new energy station, and divide the normalized operating power into a plurality of power normalized value components;

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

[0128] The power flow of the sending-end power grid is calculated according to the power per unit values ​​corresponding to multiple benchmark operating points, and the static reactive switching situation of the dynamic reactive compensation device corresponding to each benchmark operating point is obtained, and the switching situation includes the static reactive switching capacity and the number of static reactive switching groups.

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

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

[0131]

[0132] In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the ith installation location, is the no-load voltage before the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the voltage after the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the impedance of the dynamic reactive power compensation device at the ith installation location, 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 power grid at the ith installation location, is the short-circuit ratio of the dynamic reactive power compensation device at the ith installation location.

[0133] In some embodiments, the system also includes: a fluctuation judgment module, which is used to determine the historical power peak and historical power valley values ​​based on the historical power data of the new energy station of the sending-end power grid; the operating power of each benchmark operating point is added according to the historical power peak and historical power valley values, and the power fluctuation upper limit and power fluctuation lower limit of each benchmark operating point are determined; for each benchmark operating point, when the operating power of the benchmark 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 has fluctuated over a large range.

[0134] In some embodiments, the reactive power compensation module 200 is used to use the voltage clamping control bus where the dynamic reactive power compensation device is located as the PV bus for each steady-state operating mode point when the power of the sending-end power grid fluctuates over a large range; and to perform power flow calculations on the dynamic reactive power compensation devices whose steady-state operating mode points are at the upper limit or the lower limit of the power fluctuation 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 used to determine the maximum reactive power compensation amount according to the reactive power compensation amount of the voltage clamping control bus corresponding to multiple steady-state operating mode points; and determine the dynamic reactive power input capacity of each dynamic reactive power compensation device according to the maximum reactive power compensation amount and a preset stability margin coefficient.

[0136] like Figure 8 As shown, an embodiment of the present application also provides an electronic device, the electronic device 10 includes a memory 20 and a processor 30, the memory 20 stores a computer program, and when the computer program is executed by the processor 30, the processor 30 executes the steps of the configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid as in any of the above embodiments.

[0137] An embodiment of the present application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed, implements the steps of a method for optimizing the configuration of a dynamic reactive power compensation device of a new energy sending-end power grid as in any of the above embodiments.

[0138] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, electronic device and computer storage medium can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

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

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

[0141] In the 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 only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

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

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

[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 the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for executing all or part of the steps of the various embodiments of the method of the present invention through a computer device (which can be a personal computer, a server, or a network device, etc.). The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk, etc. 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 the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments 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: 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 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 where the operating power is below the rated power; 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: The method of determining the static reactive switching status of the dynamic reactive compensation device corresponding to each reference operating point according to the operating powers respectively corresponding to the multiple reference operating points of the sending-end power grid includes: 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; The power flow of the sending-end power grid is calculated according to the power per unit values ​​corresponding to the multiple reference operating points, so as to obtain the static reactive switching status of the dynamic reactive compensation device corresponding to each reference operating point, wherein the switching status includes the static reactive switching capacity and the number of static reactive switching groups.

3. 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 whose 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.

4. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 3 is characterized in that: The calculation method of the voltage stiffness index is: In the formula, is the voltage stiffness index of the dynamic reactive power compensation device at the ith installation location, is the no-load voltage before the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the voltage after the dynamic reactive power compensation device at the ith installation location is connected to the grid, is the impedance of the dynamic reactive power compensation device at the ith installation location, 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 power grid at the ith installation location, is the short-circuit ratio of the dynamic reactive power compensation device at the ith installation location.

5. 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.

6. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 5 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.

7. The configuration optimization method of the dynamic reactive power compensation device of the new energy sending-end power grid according to claim 1 or 6 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.

8. 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; 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.

9. 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 7.

10. 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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