A power grid SVG control method, system and computer device

Abstract

This invention discloses a power grid SVG control method, system, and computer equipment. The SVG control method includes the following steps: acquiring the line voltage value and three-phase current value of the SVG at the grid connection point; calculating the short-circuit ratio of the power grid SVG control system based on the acquired line voltage value and three-phase current value; matching the short-circuit ratio data with a preset segmentation range to determine the target SVG control parameter set from multiple SVG control parameter sets; and controlling the power grid SVG using the target SVG control parameter set. The power grid SVG control method can automatically adjust the SVG control parameters according to the short-circuit ratio, enabling the SVG to operate stably and reliably even when the power grid strength changes, thus achieving adaptive SVG control.

Description

Technical Field

[0001] This invention relates to the field of electrical or electronic system control technology, and in particular to a power grid SVG control method, system and computer equipment. Background Technology

[0002] SVG stands for Static Var Generator, which includes a power converter, a grid-connected reactor, and a controller. The SVG controller controls the SVG to achieve reactive power compensation. The reactive power compensation device (SVG) has functions such as reactive power compensation and grid voltage stabilization. It is a major device for improving grid quality. The impedance characteristics of the grid will affect the stability of the SVG grid-connected system.

[0003] Current SVG control methods or systems cannot automatically adapt to application scenarios with varying grid strength, which can easily lead to instability in SVG grid-connected systems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the above-mentioned shortcomings of the prior art by providing a power grid SVG control method, system and computer equipment, so that the SVG control parameters can be automatically adjusted according to the short-circuit ratio during the reactive power compensation process, so that the SVG can still operate stably and reliably when the power grid strength changes, thereby realizing adaptive power grid SVG control.

[0005] In a first aspect, the present invention provides a power grid SVG control method, the method being applied to a power grid SVG control system, the method comprising the following steps:

[0006] S1: Collect the line voltage value and three-phase current value of the SVG grid connection point;

[0007] S2: Calculate the short-circuit ratio of the power grid SVG control system based on the collected line voltage value at the SVG grid connection point and the three-phase current value of the SVG;

[0008] S3: Based on the short-circuit ratio data, match the preset segmentation range and determine the target SVG control parameter group from multiple SVG control parameter groups;

[0009] S4: Control the power grid SVG using the target SVG control parameter set.

[0010] Furthermore, step S2 specifically includes the following steps:

[0011] Step S2 includes the following steps:

[0012] S2.1: Calculate the positive sequence voltage amplitude at the grid connection point based on the line voltage value at the SVG grid connection point;

[0013] S2.2: Calculate the reactive current amplitude at the grid connection point based on the three-phase current values ​​of the SVG;

[0014] S2.3: Store the positive sequence voltage amplitude and reactive current amplitude at set intervals;

[0015] S2.4: Calculate the voltage difference ΔV based on the current positive sequence voltage amplitude and the previous positive sequence voltage amplitude. m The current difference ΔI is calculated based on the current reactive current amplitude and the previous reactive current amplitude. q ,

[0016] The voltage difference ΔV m The calculation formula is as follows:

[0017] ΔV m =V m (k)-V m (k-dT);

[0018] Where: V m (k) represents the positive sequence voltage amplitude at the current moment, V m (k-dT) is the positive sequence voltage amplitude of the previous moment;

[0019] The current difference ΔI q The calculation formula is as follows:

[0020] ΔI q =I q (k)-I q (k-dT);

[0021] Among them: I q (k) represents the reactive current amplitude at the current moment, I q (k-dT) is the reactive current amplitude at the previous moment;

[0022] S2.5: Calculate the grid impedance based on the voltage difference and current difference, voltage impedance Z s The calculation formula is as follows:

[0023]

[0024] Where: ΔV m For voltage difference, ΔI q It is the current difference;

[0025] S2.6: Calculate the short-circuit ratio of the power grid SVG control system based on the power grid impedance.

[0026] Preferably, the positive sequence voltage amplitude of the grid connection point calculated from the line voltage value of the SVG grid connection point in step S2.1 is obtained based on the Park transform method or the discrete Fourier transform method;

[0027] In step S2.2, the reactive current amplitude at the grid connection point is calculated based on the three-phase current values ​​of the SVG, which is obtained using the Park transform method or the discrete Fourier transform method.

[0028] Preferably, in step S2.6, the short-circuit ratio of the power grid SVG control system is calculated based on the power grid impedance, specifically by: calculating the short-circuit ratio of the power grid SVG control system based on the power grid impedance Z. s SVG rated capacity Q n and the rated voltage of the power supply V s The short-circuit ratio is calculated.

[0029] The formula for calculating the short-circuit ratio (SCR) is as follows:

[0030]

[0031] Among them: Z s Q is the power grid impedance. n For the rated capacity of SVG, V s This is the rated voltage of the power supply.

[0032] Preferably, step S2.6, which calculates the short-circuit ratio of the power grid SVG control system based on the power grid impedance, further includes determining whether the short-circuit ratio SCR is valid. The specific determination method is as follows:

[0033] When the current difference |ΔI q When |≥0.1pu, the value of the short-circuit ratio (SCR) is considered valid;

[0034] When the current difference |ΔI q When | < 0.1pu, the value of the short-circuit ratio (SCR) is deemed invalid.

[0035] Preferably, step S3 specifically includes the following steps:

[0036] S3.1: Set the SVG control parameter group to three groups, namely the first parameter group, the second parameter group, and the third parameter group.

[0037] The first parameter group, the second parameter group, and the third parameter group all include the set phase-locked loop proportional coefficient, phase-locked loop integral coefficient, current loop proportional coefficient, and current loop integral coefficient.

[0038] S3.2: Based on the value of the short-circuit ratio SCR, the short-circuit ratio SCR is set to three segments: the first segment when 0 < SCR ≤ 5, the second segment when 5 < SCR ≤ 10, and the third segment when SCR > 10.

[0039] S3.3: Determine the target SVG control parameter set based on the segment range and data size of the short-circuit ratio SCR:

[0040] When 0 < SCR ≤ 5, the first parameter group is determined as the target SVG control parameter group;

[0041] When 5 < SCR ≤ 10, the second parameter group is determined as the target SVG control parameter group;

[0042] When SCR > 10, the third parameter group is determined as the target SVG control parameter group.

[0043] Preferably, step S3.2 further includes: determining the switching of the SVG control parameter group, which specifically includes:

[0044] S3.2.1: Measure the short-circuit ratio three times consecutively;

[0045] S3.2.2: Determine whether to switch the target SVG control parameter group based on the results of the three short-circuit ratios. Specifically: if the values ​​of the three short-circuit ratios all fall within the same short-circuit ratio segment range, then switch to the corresponding SVG control parameter group; if the values ​​of the three short-circuit ratios do not fall within the same SCR segment range, then do not switch the SVG control parameter group.

[0046] The present invention provides a power grid SVG control method that can calculate the short-circuit ratio in real time based on the relationship between the line voltage value of the SVG grid connection point and the three-phase current value of the SVG during the reactive power compensation process of the SVG. Then, it automatically adjusts the SVG control parameter group according to the short-circuit ratio, so that the SVG can still operate stably and reliably when the power grid strength changes. It can meet the requirements of real-time performance and high precision. It performs synchronous calculation during the normal operation of the SVG, has a fast response speed, and can follow the power grid strength changes in a timely manner, thus realizing adaptive SVG control.

[0047] In addition, compared with the active current injection perturbation method, this method has the advantages of high real-time performance, low cost, and small computational load, and there will be no injected perturbation signal to affect the grid connection quality.

[0048] Secondly, the present invention provides a power grid SVG control system, including a voltage measurement module, a current measurement module, a calculation module, and an SVG control parameter switching module.

[0049] The voltage measurement module is used to collect the line voltage value at the SVG grid connection point;

[0050] The current measurement module is used to acquire the three-phase current values ​​of the SVG;

[0051] The calculation module is connected to the voltage measurement module and the current flow module respectively, and is used to calculate the short-circuit ratio of the power grid SVG control system based on the line voltage value of the SVG grid connection point and the three-phase current value of the SVG.

[0052] The SVG control parameter determination module is connected to the calculation module and is used to determine the target SVG control parameter group from multiple SVG control parameter groups by matching a preset segmentation range based on the short-circuit ratio data.

[0053] The control module is connected to the SVG control parameter determination module and is used to control the power grid SVG according to the target SVG control parameter set.

[0054] Preferably, the segmentation range of the short-circuit ratio (SCR) is set to three segments: the first segment when 0 < SCR ≤ 5, the second segment when 5 < SCR ≤ 10, and the third segment when SCR > 10.

[0055] The SVG control parameter group is set to three groups, namely the first parameter group, the second parameter group and the third parameter group. The first parameter group, the second parameter group and the third parameter group respectively include the phase-locked loop proportional coefficient, the phase-locked loop integral coefficient, the current loop proportional coefficient and the current loop integral coefficient.

[0056] The SVG control parameter determination module determines the target SVG control parameter set from multiple SVG control parameter sets by matching the short-circuit ratio data with a preset segmentation range, specifically:

[0057] When 0 < SCR ≤ 5, the SVG control parameter determination module determines the first parameter group as the target SVG control parameter group;

[0058] When 5 < SCR ≤ 10, the SVG control parameter determination module determines the second parameter group as the target SVG control parameter group;

[0059] When SCR > 10, the SVG control parameter determination module determines the third parameter group as the target SVG control parameter group.

[0060] The power grid SVG control system provided by this invention can calculate the short-circuit ratio in real time based on the relationship between the line voltage value of the SVG grid connection point and the three-phase current value of the SVG during the reactive power compensation process. Then, it automatically adjusts the SVG control parameter group according to the short-circuit ratio, so that the SVG can still operate stably and reliably when the power grid strength changes, thus realizing adaptive SVG control.

[0061] Thirdly, the present invention provides a computer device including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described power grid SVG control method.

[0062] The computer device provided by this invention can calculate the grid impedance in real time by relating the voltage difference and reactive current difference at the grid connection point to the grid impedance during the reactive power compensation process of SVG, thereby obtaining the short-circuit ratio at the grid connection point and automatically adjusting the SVG control parameters according to the short-circuit ratio, so that the SVG can still operate stably and reliably when the grid strength changes, thus realizing grid adaptive SVG control. Attached Figure Description

[0063] Figure 1 This is a flowchart of the power grid SVG control method in an embodiment of the present invention;

[0064] Figure 2 This is a schematic diagram of SVG control during grid connection in an embodiment of the present invention;

[0065] Figure 3 This is a calculation block diagram for calculating grid impedance and short-circuit ratio in an embodiment of the present invention;

[0066] Figure 4 A schematic diagram of the SVG control parameter group;

[0067] Figure 5 This is a schematic diagram of the SVG control system in an embodiment of the present invention. Detailed Implementation

[0068] To enable those skilled in the art to better understand the technical solution of the present invention, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0069] It is understood that the specific embodiments and accompanying drawings described herein are merely for explaining the invention and are not intended to limit the invention.

[0070] It is understood that, without conflict, the various embodiments and features in the embodiments of the present invention can be combined with each other.

[0071] It is understood that, for ease of description, only the parts related to the present invention are shown in the accompanying drawings, while the parts unrelated to the present invention are not shown in the drawings.

[0072] It is understood that each unit or module involved in the embodiments of the present invention may correspond to only one entity structure, or may be composed of multiple entity structures, or multiple units or modules may be integrated into one entity structure.

[0073] It is understood that, without conflict, the functions and steps marked in the flowcharts and block diagrams of this invention may occur in a different order than that marked in the accompanying drawings.

[0074] It is understood that the flowcharts and block diagrams of this invention illustrate the possible architecture, functions, and operations of systems, apparatuses, devices, and methods according to various embodiments of this invention. Each block in the flowchart or block diagram may represent a unit, module, program segment, or code, containing executable instructions for implementing the specified function. Furthermore, each block or combination of blocks in the block diagram and flowchart can be implemented using a hardware-based system to achieve the specified function, or using a combination of hardware and computer instructions.

[0075] It is understood that the units and modules involved in the embodiments of the present invention can be implemented by software or by hardware. For example, the units and modules can be located in a processor.

[0076] To address the shortcomings of existing SVG control methods or systems, which cannot automatically adapt to varying grid strength and rely on only one set of SVG control parameters, leading to instability in SVG grid-connected systems, the inventors of this application have discovered that the short-circuit ratio (SCR) can be used to achieve stable grid operation, thus solving the aforementioned problems. Because the SCR characterizes grid strength, a higher SCR corresponds to a lower equivalent impedance, indicating a stronger grid and a more stable SVG grid-connected system. Therefore, this invention provides a grid SVG control method and system. This method or system can switch control modes by employing multiple sets of SVG control parameters based on changes in the SCR, thereby achieving adaptive dynamic performance adjustment of the SVG under different grid strengths and maintaining stable system operation.

[0077] Example 1:

[0078] This embodiment provides a power grid SVG control method, which is applied to a power grid SVG control system, such as... Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the power grid SVG control method includes steps S1 to S4:

[0079] S1: Collect the line voltage and three-phase current values ​​of the SVG grid connection point.

[0080] Specific ways to obtain it are as follows Figure 2 As shown, the SVG power conversion (which can be accomplished using an SVG power converter) employs N (N=40) H-bridge modules cascaded per phase to form a three-phase star-connected SVG (Static Var Generator) multilevel converter. The SVG (which can be implemented using an SVG controller) controls the voltage acquisition module and current acquisition module in the acquisition unit to acquire the line voltage value (V) at the SVG grid connection point. ab V bc V ca ) and SVG three-phase current value (Ia I b I c ).

[0081] S2: Calculate the short-circuit ratio of the power grid SVG control system based on the collected line voltage value at the SVG grid connection point and the SVG three-phase current value.

[0082] Specifically, such as Figure 3 As shown, the specific process for calculating the short-circuit ratio of the power grid SVG control system in S2 is as follows:

[0083] S2.1: Calculate the positive sequence voltage amplitude at the grid connection point based on the line voltage value at the SVG grid connection point;

[0084] Specifically, in S2.1, the positive-sequence voltage amplitude of the grid connection point is calculated based on the line voltage value of the SVG grid connection point, which is obtained using either the Park transform method or the Discrete Fourier Transform method. In S2.2, the reactive current amplitude of the grid connection point is calculated based on the three-phase current value of the SVG, which is also obtained using either the Park transform method or the Discrete Fourier Transform method. The Park transform, also known as the Park transformation, is used to perform coordinate transformation. The Discrete Fourier Transform (DFT) is a Fourier transform that presents a discrete form in both the time and frequency domains, transforming the sampling of a time-domain signal into a sampling in the frequency domain of the discrete-time Fourier transform.

[0085] S2.2: Calculate the reactive current amplitude at the grid connection point based on the three-phase current values ​​of the SVG;

[0086] S2.3: Store the positive sequence voltage amplitude and reactive current amplitude at set intervals;

[0087] S2.4: Calculate the voltage difference ΔV based on the current positive sequence voltage amplitude and the previous positive sequence voltage amplitude. m The current difference ΔI is calculated based on the current reactive current amplitude and the previous reactive current amplitude. q ,

[0088] The voltage difference ΔV m The calculation formula is as follows:

[0089] ΔV m =V m (k)-V m (k-dT);

[0090] Where: ΔV m For voltage difference, ΔI q For the current difference, V m (k) represents the positive sequence voltage amplitude at the current moment, V m(k-dT) is the positive sequence voltage amplitude of the previous moment;

[0091] The current difference ΔI q The calculation formula is as follows:

[0092] ΔI q =I q (k)-I q (k-dT);

[0093] Among them: I q (k) represents the reactive current amplitude at the current moment, I q (k-dT) is the reactive current amplitude at the previous moment;

[0094] S2.5: Calculate the grid impedance based on the voltage difference and current difference, voltage impedance Z s The calculation formula is as follows:

[0095]

[0096] Where: ΔV m For voltage difference, ΔI q It is the current difference;

[0097] S2.6: Calculate the short-circuit ratio of the power grid SVG control system based on the power grid impedance.

[0098] Specifically, in S2.6, it is based on the grid impedance Z. s SVG rated capacity Q n and the rated voltage of the power supply V s The short-circuit ratio is calculated.

[0099] The formula for calculating the short-circuit ratio (SCR) is as follows:

[0100]

[0101] Among them: Z s Q is the power grid impedance. n For the rated capacity of SVG, V s This is the rated voltage of the power supply.

[0102] To improve control, S2.6 also includes a method for determining the validity of the short-circuit ratio (SCR) value, as follows:

[0103] When the current difference |ΔI q When |≥0.1pu, the value of the short-circuit ratio (SCR) is considered valid;

[0104] When the current difference |ΔI q When | < 0.1pu, the value of the short-circuit ratio (SCR) is deemed invalid.

[0105] S3: Based on the short-circuit ratio data, match the preset segmentation range and determine the target SVG control parameter group from multiple SVG control parameter groups;

[0106] Specifically, S3 includes the following steps:

[0107] S3.1: Set the SVG control parameter group to three groups, namely the first parameter group, the second parameter group, and the third parameter group.

[0108] The first parameter group, the second parameter group, and the third parameter group all include the set phase-locked loop proportional coefficient, phase-locked loop integral coefficient, current loop proportional coefficient, and current loop integral coefficient.

[0109] S3.2: Based on the value of the short-circuit ratio SCR, the short-circuit ratio SCR is set to three segments: the first segment when 0 < SCR ≤ 5, the second segment when 5 < SCR ≤ 10, and the third segment when SCR > 10.

[0110] S3.3: Determine the target SVG control parameter set based on the segment range and data size of the short-circuit ratio SCR:

[0111] When 0 < SCR ≤ 5, the first parameter group is determined as the target SVG control parameter group;

[0112] When 5 < SCR ≤ 10, the second parameter group is determined as the target SVG control parameter group;

[0113] When SCR > 10, the third parameter group is determined as the target SVG control parameter group.

[0114] To avoid frequent switching of SVG control parameter groups, S3.2 also includes: determining the switching of SVG control parameter groups, which specifically includes:

[0115] S3.2.1: Measure the short-circuit ratio three times consecutively;

[0116] S3.2.2: Determine whether to switch the target SVG control parameter group based on the results of the three short-circuit ratios. Specifically: if the values ​​of the three short-circuit ratios all fall within the same short-circuit ratio segment range, then switch to the corresponding SVG control parameter group; if the values ​​of the three short-circuit ratios do not fall within the same SCR segment range, then do not switch the SVG control parameter group.

[0117] S3.3: Determine the target SVG control parameter set based on the segment range and data size of the short-circuit ratio SCR:

[0118] When 0 < SCR ≤ 5, the first parameter group is determined as the target SVG control parameter group;

[0119] When 5 < SCR ≤ 10, the second parameter group is determined as the target SVG control parameter group;

[0120] When SCR > 10, the third parameter group is determined as the target SVG control parameter group.

[0121] S4: Control the power grid SVG using the target SVG control parameter set.

[0122] The target SVG control parameter group includes parameters such as phase-locked loop proportional coefficient, phase-locked loop integral coefficient, current loop proportional coefficient, and current loop integral coefficient. The power grid SVG is controlled based on these parameters.

[0123] The power grid SVG control method in this embodiment can calculate the short-circuit ratio in real time based on the relationship between the line voltage value of the SVG grid connection point and the three-phase current value of the SVG during the reactive power compensation process. Then, it automatically adjusts the SVG control parameter group according to the short-circuit ratio, so that the SVG can still operate stably and reliably when the power grid strength changes. It can meet the requirements of real-time performance and high precision. It performs synchronous calculations during the normal operation of the SVG, has a fast response speed, and can follow the changes in power grid strength in a timely manner, thus realizing adaptive SVG control.

[0124] In addition, the method in this embodiment has advantages over the active current injection perturbation method, such as high real-time performance, low cost, and small computational load, and there is no injected perturbation signal to affect the grid connection quality.

[0125] Example 2:

[0126] This embodiment provides a power grid SVG control system, such as Figure 5 As shown, the power grid SVG control system includes a voltage measurement module, a current measurement module, a calculation module, an SVG control parameter determination module, and a control module.

[0127] The voltage measurement module is used to acquire the line voltage value at the SVG grid connection point;

[0128] The current measurement module is used to acquire the three-phase current values ​​of the SVG.

[0129] The calculation module is connected to the voltage measurement module and the current flow module respectively, and is used to calculate the short-circuit ratio of the power grid SVG control system based on the line voltage value of the SVG grid connection point and the three-phase current value of the SVG.

[0130] The SVG control parameter determination module is connected to the calculation module and is used to match the preset segmentation range based on the short-circuit ratio data to determine the target SVG control parameter set from multiple SVG control parameter sets.

[0131] The control module is connected to the SVG control parameter determination module and is used to control the power grid SVG using the target SVG control parameter set.

[0132] Specifically, such as Figure 2 and Figure 3 As shown, the positive-sequence voltage amplitude at the grid connection point is first calculated based on the line voltage value of the SVG grid connection point. Then, the reactive current amplitude at the grid connection point is calculated based on the three-phase current value of the SVG. The positive-sequence voltage amplitude and reactive current amplitude are then stored at set intervals. Finally, the voltage difference ΔV is calculated based on the current positive-sequence voltage amplitude and the positive-sequence voltage amplitude from the previous moment. m The current difference ΔI is calculated based on the current reactive current amplitude and the previous reactive current amplitude. q The grid connection point voltage measurement module and grid connection current measurement module can reuse the PT (voltage transformer) and CT (current transformer) hardware in the current SVG system without increasing costs or affecting the grid connection operation of the current SVG system.

[0133] Working principle as follows Figure 2 As shown, the SVG system uses PWM pulse width modulation control technology to achieve rapid dynamic regulation of reactive power through power conversion, specifically by adjusting the line voltage and three-phase current values ​​at the SVG grid connection point. The specific working process is as follows: Figure 5 As shown, firstly, the voltage measurement module collects the line voltage value at the SVG grid connection point, and the current measurement module collects the three-phase current value of the SVG. Then, the calculation module calculates the short-circuit ratio of the power grid SVG control system based on the line voltage value at the SVG grid connection point and the three-phase current value of the SVG. Next, the SVG control parameter determination module matches the short-circuit ratio data with a preset segmentation range and determines the target SVG control parameter set from multiple SVG control parameter sets. Finally, the control module connects with the SVG control parameter determination module to control the power grid SVG using the target SVG control parameter set.

[0134] Voltage difference ΔV m The calculation formula is as follows:

[0135] ΔV m =V m (k)-V m (k-dT);

[0136] Where: ΔV m For voltage difference, ΔI q For the current difference, V m (k) represents the positive sequence voltage amplitude at the current moment, V m (k-dT) is the positive sequence voltage amplitude of the previous moment;

[0137] Current difference ΔI q The calculation formula is as follows:

[0138] ΔI q =I q(k)-I q (k-dT);

[0139] Among them: I q (k) represents the reactive current amplitude at the current moment, I q (k-dT) represents the reactive current amplitude at the previous moment:

[0140] The grid impedance is then calculated based on the voltage and current differences, specifically the voltage impedance Z. s The calculation formula is as follows:

[0141]

[0142] Where: ΔV m For voltage difference, ΔI q It is the current difference;

[0143] Finally, the short-circuit ratio (SCR) of the power grid SVG control system is calculated based on the power grid impedance. The formula for calculating the short-circuit ratio (SCR) is as follows:

[0144]

[0145] Among them: Z s Q is the power grid impedance. n For the rated capacity of SVG, V s This is the rated voltage of the power supply.

[0146] Note: The parts that are the same as in Example 1 are not described in detail.

[0147] In this embodiment, there are multiple SVG control parameter groups, specifically, such as... Figure 4 As shown, the SVG control parameter group is set to three groups, namely the first parameter group, the second parameter group and the third parameter group. The first parameter group, the second parameter group and the third parameter group respectively include the phase-locked loop proportional coefficient, the phase-locked loop integral coefficient, the current loop proportional coefficient and the current loop integral coefficient.

[0148] The segmentation range of the short-circuit ratio (SCR) is also set to three segments: the first segment when 0 < SCR ≤ 5, the second segment when 5 < SCR ≤ 10, and the third segment when SCR > 10.

[0149] The SVG control parameter determination module matches a preset segmentation range with the short-circuit ratio data and determines the target SVG control parameter set from multiple SVG control parameter sets, specifically:

[0150] When 0 < SCR ≤ 5, the SVG control parameter determination module selects the first parameter group as the target SVG control parameter group;

[0151] When 5 < SCR ≤ 10, the SVG control parameter determination module selects the second parameter group as the target SVG control parameter group.

[0152] When SCR > 10, the SVG control parameter determination module selects the third parameter group as the target SVG control parameter group.

[0153] In this embodiment, the power grid SVG control system can calculate the short-circuit ratio in real time based on the relationship between the line voltage value of the SVG grid connection point and the three-phase current value of the SVG during the reactive power compensation process. Then, it automatically adjusts the SVG control parameter group according to the short-circuit ratio, so that the SVG can still operate stably and reliably when the power grid strength changes, thus realizing adaptive SVG control.

[0154] Example 3:

[0155] This embodiment provides a computer device, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps of the above-described power grid SVG control method.

[0156] The computer equipment provided in this embodiment can calculate the grid impedance in real time by relating the voltage difference and reactive current difference at the grid connection point to the grid impedance during the reactive power compensation process of SVG, thereby obtaining the short-circuit ratio at the grid connection point and automatically adjusting the SVG control parameters according to the short-circuit ratio, so that the SVG can still operate stably and reliably when the grid strength changes, thus realizing grid adaptive SVG control.

[0157] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A power grid SVG control method, the method is applied to a power grid SVG control system, characterized in that, The method includes the following steps: S1: Collect the line voltage value and three-phase current value of the SVG grid connection point; S2: Calculate the short-circuit ratio of the power grid SVG control system based on the collected line voltage value at the SVG grid connection point and the three-phase current value of the SVG; S2 includes the following steps: S2.1: Calculate the positive sequence voltage amplitude at the grid connection point based on the line voltage value at the SVG grid connection point; S2.2: Calculate the reactive current amplitude at the grid connection point based on the three-phase current values ​​of the SVG; S2.3: Store the positive sequence voltage amplitude and reactive current amplitude at set intervals; S2.4: Calculate the voltage difference based on the current positive-sequence voltage amplitude and the previous positive-sequence voltage amplitude. The current difference is calculated based on the current reactive current amplitude and the previous reactive current amplitude. , The voltage difference The calculation formula is as follows: ； in: For voltage difference, For current difference, This represents the positive sequence voltage amplitude at the current moment. This represents the positive sequence voltage amplitude from the previous moment. The current difference The calculation formula is as follows: ； in: The reactive current amplitude at the current moment. This represents the reactive current amplitude at the previous moment. S2.5: Calculate the grid impedance based on the voltage difference and current difference, voltage impedance The calculation formula is as follows: in: For voltage difference, It is the current difference; S2.6: Calculate the short-circuit ratio of the power grid SVG control system based on the power grid impedance; S3: Based on the short-circuit ratio data, match the preset segmentation range and determine the target SVG control parameter group from multiple SVG control parameter groups; S3 specifically includes the following steps: S3.1: Set the SVG control parameter group to three groups: the first parameter group, the second parameter group, and the third parameter group. The first parameter group, the second parameter group, and the third parameter group all include the set phase-locked loop proportional coefficient, phase-locked loop integral coefficient, current loop proportional coefficient, and current loop integral coefficient. S3.2: Based on the value of the short-circuit ratio (SCR), the short-circuit ratio (SCR) is set to three segments, namely... The first paragraph of time The second paragraph of time, The third paragraph; S3.3: Determine the target SVG control parameter set based on the segment range and data size of the short-circuit ratio SCR: when At that time, the first parameter group is determined as the target SVG control parameter group; when At that time, the second parameter group is determined as the target SVG control parameter group; when At that time, the third parameter group is determined as the target SVG control parameter group; S4: Control the power grid SVG using the target SVG control parameter set.

2. The power grid SVG control method according to claim 1, characterized in that, The positive sequence voltage amplitude of the grid connection point calculated from the line voltage value of the SVG grid connection point in S2.1 is obtained based on the Park transform method or the discrete Fourier transform method; The reactive current amplitude at the grid connection point calculated based on the three-phase current values ​​of the SVG in S2.2 is obtained using the Park transform method or the discrete Fourier transform method.

3. The power grid SVG control method according to claim 1, characterized in that, In step S2.6, the short-circuit ratio of the power grid SVG control system is calculated based on the power grid impedance. Specifically, this is done by calculating the short-circuit ratio based on the power grid impedance. SVG rated capacity and rated voltage of power supply The short-circuit ratio is calculated. The formula for calculating the short-circuit ratio (SCR) is as follows: in: For grid impedance, For SVG rated capacity, This is the rated voltage of the power supply.

4. The power grid SVG control method according to claim 1, characterized in that, S2.6 further includes: determining whether the short-circuit ratio (SCR) value is valid, the determination method being as follows: when When the short-circuit ratio (SCR) is determined to be valid, the value of the SCR is considered valid. When the current difference When this happens, the value of the short-circuit ratio (SCR) is deemed invalid.

5. The power grid SVG control method according to claim 1, characterized in that, S3.2 further includes: determining the switching of the SVG control parameter group, which specifically includes: S3.2.1: Measure the short-circuit ratio three times consecutively; S3.2.2: Determine whether to switch the target SVG control parameter group based on the results of the three short-circuit ratios. Specifically: if the values ​​of the three short-circuit ratios all fall within the same short-circuit ratio segment range, then switch to the corresponding SVG control parameter group; if the values ​​of the three short-circuit ratios do not fall within the same SCR segment range, then do not switch the SVG control parameter group.

6. A power grid SVG control system, characterized in that, It includes a voltage measurement module, a current measurement module, a calculation module, an SVG control parameter determination module, and a control module. The voltage measurement module is used to collect the line voltage value at the SVG grid connection point; The current measurement module is used to acquire the three-phase current values ​​of the SVG; The calculation module is connected to the voltage measurement module and the current measurement module respectively, and is used to calculate the short-circuit ratio of the power grid SVG control system based on the line voltage value of the SVG grid connection point and the three-phase current value of the SVG. The short-circuit ratio of the power grid SVG control system is calculated based on the collected line voltage and three-phase current values ​​of the SVG grid connection point, specifically including: The positive sequence voltage amplitude of the grid connection point is calculated based on the line voltage value of the SVG grid connection point; The reactive current amplitude at the grid connection point is calculated based on the three-phase current values ​​of the SVG. The positive sequence voltage amplitude and reactive current amplitude are stored at set intervals. The voltage difference is calculated based on the current positive-sequence voltage amplitude and the previous positive-sequence voltage amplitude. The current difference is calculated based on the current reactive current amplitude and the previous reactive current amplitude. , The voltage difference The calculation formula is as follows: ； in: For voltage difference, For current difference, This represents the positive sequence voltage amplitude at the current moment. This represents the positive sequence voltage amplitude from the previous moment. The current difference The calculation formula is as follows: ； in: The reactive current amplitude at the current moment. This represents the reactive current amplitude at the previous moment. Calculate the grid impedance based on the voltage difference and current difference, voltage impedance. The calculation formula is as follows: in: For voltage difference, It is the current difference; The short-circuit ratio of the power grid SVG control system is calculated based on the power grid impedance. The SVG control parameter determination module is connected to the calculation module and is used to determine the target SVG control parameter group from multiple SVG control parameter groups by matching a preset segmentation range based on the short-circuit ratio data. The control module is connected to the SVG control parameter determination module and is used to control the power grid SVG according to the target SVG control parameter set; The short-circuit ratio (SCR) is segmented into three segments, namely: The first paragraph of time The second paragraph of the time, and The third paragraph; The SVG control parameter group is set to three groups, namely the first parameter group, the second parameter group and the third parameter group. The first parameter group, the second parameter group and the third parameter group respectively include the phase-locked loop proportional coefficient, the phase-locked loop integral coefficient, the current loop proportional coefficient and the current loop integral coefficient. The SVG control parameter determination module determines the target SVG control parameter set from multiple SVG control parameter sets by matching the short-circuit ratio data with a preset segmentation range, specifically: when At that time, the SVG control parameter determination module determines the first parameter group as the target SVG control parameter group; when At that time, the SVG control parameter determination module determines the second parameter group as the target SVG control parameter group; when At that time, the SVG control parameter determination module determines the third parameter group as the target SVG control parameter group.

7. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

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