A power distribution network operation and maintenance voltage unbalance degree suppression method, device and apparatus

Abstract

The application relates to the technical field of power distribution systems, in particular to a voltage unbalance degree suppression method, equipment and device for power distribution network operation and maintenance, which comprises the following steps: acquiring three-phase phase voltages, three-phase line currents, active power and reactive power at each monitoring point of a power distribution network, and counting negative sequence voltage unbalance degrees of the monitoring points to determine whether the unbalance degrees exceed a limit value; acquiring voltage balance instantaneous deviation characteristic values to obtain voltage imbalance change difference characteristic values, and then acquiring an adjustment coefficient of a voltage unbalance degree suppression processing compensation response of the power distribution network; adjusting a droop coefficient of a droop control strategy according to the adjustment coefficient, and then acquiring a droop control function of negative sequence reactive power compensation of the power distribution network to suppress the negative sequence voltage unbalance degree of the power distribution network. The application can improve the suppression effect of the voltage unbalance degree of the power distribution network.

Description

Technical Field

[0001] This application relates to the field of power distribution system technology, specifically to a method, equipment, and apparatus for suppressing voltage imbalance in power distribution network operation and maintenance. Background Technology

[0002] If voltage imbalance exceeds the safety threshold during distribution network operation, it will lead to a decrease in the operating efficiency of three-phase asynchronous motors, causing severe motor overheating and affecting their stable operation. For precision electronic equipment, three-phase voltage asymmetry may cause malfunctions and damage. Furthermore, voltage imbalance during distribution network operation also increases line losses. Therefore, effectively suppressing voltage imbalance during distribution network operation can ensure the power supply quality at the user end of the power system, improve distribution network operating efficiency, and maintain the safe and stable operation of the power system.

[0003] However, during the operation of the distribution network, load changes can lead to voltage imbalances. The voltage imbalance suppression process is affected by various interference factors, resulting in poor adjustment of the actual voltage imbalance. Droop control is a commonly used method for suppressing voltage imbalance in distribution networks. Combined with droop control characteristics, it can effectively suppress voltage imbalances in the distribution network. However, due to differences in load characteristics, line impedance, and system operating state characteristics, if the deviation of the droop coefficient during droop control is large, it can lead to insufficient or excessive compensation, exacerbating voltage fluctuations in the distribution network. This fails to meet the requirements for suppressing voltage imbalance under the influence of multiple interferences and resulting in poor stability of the distribution network operation. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this application is to provide a method, equipment, and device for suppressing voltage imbalance in distribution network operation and maintenance. The specific technical solution adopted is as follows: In a first aspect, embodiments of this application provide a method for suppressing voltage imbalance in distribution network operation and maintenance, comprising the following steps: The three-phase phase voltage, three-phase line current, active power and reactive power at each monitoring point of the distribution network are obtained, and the negative sequence voltage imbalance at each monitoring point is calculated to determine whether it exceeds the limit. Suppression measures are implemented to address situations where negative sequence voltage imbalance exceeds the limit, specifically including: Based on the degree of difference in phase voltage at each time and the power distribution deviation of different phases at each time, the instantaneous deviation characteristic value of voltage balance at each time is obtained; based on the changing trend and dispersion of the instantaneous deviation characteristic value of voltage balance and the voltage unbalance, and combined with the correlation between the instantaneous deviation characteristic value of voltage balance and the voltage unbalance, the difference characteristic value of voltage imbalance at each time is obtained; and the adjustment coefficient of the voltage unbalance suppression and compensation response of the distribution network is obtained by the average level of the difference characteristic value of voltage imbalance. The droop coefficient of the droop control strategy is adjusted according to the adjustment coefficient, thereby obtaining the droop control function for negative sequence reactive power compensation in the distribution network, so as to suppress the negative sequence voltage imbalance of the distribution network.

[0005] Preferably, the average of the absolute values ​​of the differences between the phase voltage of each phase and the phase voltage of other phases at each time moment is calculated, and the ratio of this average value to the phase voltage of each phase is used as the first characteristic value of the phase voltage balance deviation at each time moment. The ratio of the reactive power of each phase to the sum of the reactive power of all phases and the ratio of the useful power of each phase to the sum of the active power of all phases are calculated at each time moment, and the average of the two ratios is used as the second characteristic value of the phase voltage balance deviation at each time moment.

[0006] Preferably, the acquisition of the instantaneous voltage balance deviation characteristic values ​​at each moment is further described as follows: ,in Indicates the first The characteristic value of the instantaneous deviation of voltage balance at each moment; and They represent the first At the [time]th moment The first and second characteristic values ​​of the phase voltage balance deviation.

[0007] Preferably, the voltage imbalance degree and the characteristic value of instantaneous voltage balance deviation at each time point and all previous time points are sorted in chronological order. The trend statistics and coefficient of variation of the two sorted sequences are calculated separately. The product of the trend statistics and coefficient of variation corresponding to the voltage imbalance degree is used as the voltage imbalance degree change coefficient at each time point. The product of the trend statistics and coefficient of variation corresponding to the instantaneous voltage balance deviation characteristic value is used as the cumulative change coefficient of balance deviation at each time point. The mean of the voltage imbalance change coefficient and the cumulative change coefficient of balance deviation is used as the first characteristic coefficient of the voltage imbalance change difference at each time point.

[0008] Preferably, the acquisition of characteristic values ​​of voltage imbalance changes at different times is further as follows: ;in, Indicates the first Characteristic values ​​of voltage imbalance changes at each moment; and They represent the first The first and second characteristic coefficients corresponding to each time point are: the absolute value of the Pearson correlation coefficient between the voltage balance instantaneous deviation characteristic value and the voltage imbalance degree at each time point and all previous time points, which is used as the second characteristic coefficient corresponding to each time point.

[0009] Preferably, the mean of the normalized processing results of all voltage imbalance change difference characteristic values ​​obtained up to the start time of the negative sequence voltage imbalance suppression treatment is used as the adjustment coefficient of the compensation response of the distribution network voltage imbalance suppression treatment.

[0010] Preferably, the adjustment coefficient of the distribution network voltage imbalance suppression and compensation response is further obtained as follows: ;in, Indicates the droop coefficient; and These represent the maximum power change and the maximum effective voltage change under steady-state operation of the distribution network, respectively. For the three-phase phase voltage, the Clark transformation and dual synchronous rotating coordinate transformation are used to obtain the corresponding negative sequence component and positive sequence component, and the effective value of the negative sequence component voltage is statistically analyzed. The maximum effective voltage change is the difference between the maximum and minimum effective values ​​of the negative sequence component voltage obtained under steady-state operation of the distribution network. This represents the adjustment coefficient for the compensation response to suppress voltage imbalance in the distribution network.

[0011] Preferably, the droop control function for obtaining the negative sequence reactive power compensation of the distribution network includes: ;in, Indicates a reference value for reactive power compensation; This represents the baseline value for reactive power. Indicates a reference value for voltage. Indicates the droop coefficient. This represents the effective value of the negative sequence component voltage obtained at the current moment.

[0012] Secondly, embodiments of this application also provide a voltage imbalance suppression device for distribution network operation and maintenance, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-described voltage imbalance suppression methods for distribution network operation and maintenance.

[0013] Thirdly, embodiments of this application also provide a voltage imbalance suppression device for distribution network operation and maintenance, wherein the device stores a computer program, and when the computer program is executed by a processor, it implements any one of the voltage imbalance suppression methods for distribution network operation and maintenance described above.

[0014] As can be seen from the above, the voltage imbalance suppression method, equipment, and apparatus for distribution network operation and maintenance provided in this application have at least the following beneficial effects: This application takes into account that during the operation and maintenance of the distribution network, the load ratio changes significantly at different stages, resulting in large differences in response during voltage imbalance compensation. This can lead to insufficient or excessive compensation, affecting the effectiveness of voltage imbalance suppression. Therefore, this application collects monitoring data at key nodes of the power system and calculates the negative sequence voltage imbalance degree based on the collected monitoring data to determine whether the power imbalance state exceeds the limit, so as to compensate and adjust the power imbalance state of the power system. Furthermore, based on the monitoring data collected at the nodes, this application combines the balance deviation caused by changes in load ratio at different stages to accurately analyze the voltage imbalance characteristics of the distribution network. By dynamically adjusting the droop control coefficient through the analysis results, precise compensation for voltage imbalance is achieved. Its beneficial effect lies in fully combining the differences in the phased balance deviation changes of the power system under voltage imbalance conditions, accurately compensating and adjusting the voltage imbalance of the power system, and improving the voltage imbalance suppression effect of distribution network operation and maintenance. Attached Figure Description

[0015] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A flowchart of the steps for a voltage imbalance suppression method in distribution network operation and maintenance provided in this application; Figure 2 This is a schematic diagram illustrating the process of obtaining the instantaneous deviation characteristic values ​​of voltage balance at various times, as provided in the embodiments of this application. Detailed Implementation

[0017] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a voltage imbalance suppression method, device, and apparatus for distribution network operation and maintenance proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise specified and limited, terms such as “comprising,” “including,” or any other variations thereof are intended to cover a non-exclusive inclusion, such that a circuit structure, article, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the article or device that includes said element. Furthermore, the term “and / or” as used herein includes any and all combinations of one or more of the associated listed items. All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0019] The following description, in conjunction with the accompanying drawings, details the specific scheme of the voltage imbalance suppression method, equipment, and device for distribution network operation and maintenance provided in this application.

[0020] Please see Figure 1 The document illustrates a flowchart of a voltage imbalance suppression method for distribution network operation and maintenance according to an embodiment of this application, including the following steps: Step 1: Obtain the three-phase phase voltage, three-phase line current, active power and reactive power at each monitoring point of the distribution network, and calculate the negative sequence voltage imbalance at each monitoring point to determine whether it exceeds the limit.

[0021] In the process of suppressing voltage imbalance in distribution networks, the voltage balance status of the distribution network must first be monitored and assessed. Based on the monitoring and assessment results, corresponding suppression measures are then implemented to address the voltage imbalance. Specifically, monitoring points are set up at key nodes in the distribution network, and smart meters are installed at each monitoring point to collect the three-phase voltage data. Three-phase line current Active power (P) and reactive power (Q), among which, These are the phase voltages of phases a, b, and c, respectively. These are the line currents of phases a, b, and c, respectively. In this embodiment, the key nodes include the low-voltage side outlet position of the distribution network transformer, the feeder sectionalizing switch position, and the distributed power source input point position. The data acquisition time interval is 1 second.

[0022] Due to the complex operating environment of the power distribution network, there is a lot of environmental noise and electromagnetic noise interference during data acquisition and transmission, resulting in poor data quality. Therefore, in this embodiment, a wavelet threshold denoising algorithm is used to denoise the acquired data to reduce the impact of high-frequency interference noise on the quality of the acquired power distribution network monitoring data. After denoising, the data is subjected to abnormal data detection and processing based on the Laida criterion to avoid the impact of abnormal deviation data on the accuracy of power distribution network operation status judgment. The specific wavelet threshold denoising algorithm processing and the abnormal detection and processing based on the Laida criterion are well known to those skilled in the art and will not be described in detail here.

[0023] Based on the preprocessed data, the voltage imbalance at each monitoring point at each time point is calculated. The voltage instability state of the distribution network is then assessed based on the calculation results. It should be noted that the voltage imbalance analysis and calculation process is well-known to those skilled in the art. Specifically, in this embodiment, the voltage imbalance is calculated using a symmetrical component algorithm according to the GB / T15543-2008 standard. For each monitoring point, the collected data is first... As input, the Clark transform and dual-synchronous rotational coordinate transformation are used to obtain the corresponding negative-sequence and positive-sequence components, and the effective value of the corresponding negative-sequence component is calculated. and the effective value of the positive sequence component The corresponding negative sequence voltage unbalance is: According to GB / T 15543—2008 "Power Quality Three-Phase Voltage Imbalance", during the operation of the power system, the negative sequence voltage imbalance at the monitoring point shall not exceed the limit of 2%, and the short-time negative sequence voltage imbalance shall not exceed the limit of 4%. The short-time negative sequence voltage imbalance refers to the peak value of the monitoring and calculation results within 1 minute. Based on the above provisions, the voltage imbalance status of each monitoring point is monitored and judged. If the negative sequence voltage imbalance calculated at the current monitoring point exceeds the above limit, the voltage imbalance suppression processing of the distribution network is initiated.

[0024] Step 2: Based on the degree of difference in phase voltage at each time and the power distribution deviation of different phases at each time, obtain the instantaneous voltage balance deviation characteristic value at each time. Based on the changing trend and dispersion of the instantaneous voltage balance deviation characteristic value and the voltage unbalance degree, and combined with the correlation between the instantaneous voltage balance deviation characteristic value and the voltage unbalance degree, obtain the voltage imbalance change difference characteristic value at each time. Obtain the adjustment coefficient of the distribution network voltage imbalance suppression and compensation response by using the average level of the voltage imbalance change difference characteristic value.

[0025] During power system operation, if the monitored negative sequence voltage imbalance exceeds the limit, a voltage imbalance suppression procedure will be initiated to suppress it. However, due to the complexity of the causes of voltage imbalance in the distribution network, and the differences in the impact of various disturbances, insufficient or delayed compensation may occur during the actual suppression process, resulting in poor voltage imbalance suppression in the distribution network and causing instability in power system operation.

[0026] Therefore, based on the judgment results of the node voltage imbalance state during the power system operation process described above, dynamic change characteristic analysis is performed on the monitoring data of the power grid collected at the cutoff time of voltage imbalance suppression. Combined with the differences in dynamic characteristics of the monitoring data caused by different interference effects, the compensation in the actual suppression process is dynamically adjusted, thereby improving the suppression effect on the distribution network voltage imbalance state. The specific analysis and processing process of the distribution network voltage imbalance characteristics during distribution network operation and maintenance is as follows: First, considering the complex characteristics of voltage imbalance during power system operation, the dynamic changes in grid parameters at nodes in the distribution network vary significantly at different stages, affecting the effectiveness of grid imbalance compensation. Therefore, for each monitoring point, including three-phase phase voltage, three-phase line current, active power, and reactive power, all monitoring data collected up to the current voltage imbalance time are normalized. Based on the processing results, the temporal variation differences between different phases during the monitoring process are analyzed. It should be noted that there are many existing normalization methods, and implementers can choose their own. This embodiment does not impose any special restrictions on this. This embodiment uses the maximum value normalization method, the specific process of which is existing technology and will not be elaborated here.

[0027] Specifically, for the processed three-phase voltage data, the average absolute value of the difference between each phase voltage and the other phase voltages at each moment is calculated. The ratio of this average value to the phase voltage of each phase is used as the first characteristic value of the phase voltage balance deviation at each moment. The larger the first characteristic value, the greater the parameter fluctuation caused by single-phase load changes during actual processing. Furthermore, considering the imbalance in load distribution between different phases under voltage imbalance conditions, leading to a significant deviation in the actual power allocation ratio, the ratio of reactive power in each phase to the sum of reactive power in all phases and the ratio of useful power in each phase to the sum of active power in all phases are calculated at each moment. The average of these two ratios is used as the second characteristic value of the voltage balance deviation in each phase at each moment. The larger the second characteristic value, the greater the instantaneous power difference under load imbalance.

[0028] Based on the above analysis, a comprehensive analysis is conducted on the instantaneous characteristics of the voltage balance deviation of each phase at each moment during the monitoring process. The characteristic value of the instantaneous voltage balance deviation at each moment is obtained based on the first and second characteristic values ​​of the voltage balance deviation at each moment. The calculation formula is as follows: ,in Indicates the first The characteristic value of the instantaneous deviation of voltage balance at each moment; and They represent the first At the [time]th moment The first and second characteristic values ​​of the phase voltage balance deviation, i.e. The larger the value, the more significant the difference in instantaneous deviation of the balance of a single phase of the power grid due to load imbalance.

[0029] Specifically, the flowchart for obtaining the instantaneous deviation characteristic values ​​of voltage balance at various times is shown below. Figure 2 As shown.

[0030] Furthermore, the instantaneous voltage balance deviation characteristic values ​​corresponding to each moment and all previous moments are sorted in chronological order. The trend statistics and coefficient of variation of the sorted sequence are then statistically analyzed. It should be noted that the trend statistics of the sequence are obtained in this embodiment using the MK trend verification algorithm. The specific process of obtaining the trend statistics using the MK trend verification algorithm is existing technology and is not specifically limited in this embodiment, so it will not be elaborated here. Similarly, the calculation process for the coefficient of variation is existing technology known to those skilled in the art, and the specific calculation process will not be elaborated here. The product of the obtained trend statistics and coefficient of variation at each moment is used as the cumulative change coefficient of the balance deviation at each moment, representing the difference in the cumulative change of the balance deviation at different stages during the operation of the power system.

[0031] Based on the above analysis, during the operation and maintenance of the distribution network, the instantaneous characteristics of the three-phase voltage and active and reactive power of different nodes are analyzed by combining the characteristic differences of the interference that causes voltage imbalance. Furthermore, the differences in the load ratio of different phases are comprehensively analyzed to accurately analyze the differences in the instantaneous balance deviation at each moment. In addition, the cumulative deviation characteristics of the power system nodes at different stages are extracted to reflect the differences in the stage-specific balance state.

[0032] Furthermore, since the voltage imbalance compensation in the distribution network is mainly achieved by adjusting reactive power, the characteristics of load distribution imbalance vary significantly at different stages of operation, resulting in large differences in negative sequence voltage changes and corresponding differences in the cumulative changes of voltage imbalance. Consequently, the adjustment differences in the balance compensation of the droop control are also greater. Therefore, by combining the stage-specific changes in voltage imbalance and the stage-specific differences in balance changes during power system operation, a precise analysis of the stage-specific changes in voltage imbalance in the distribution network is conducted, and the characteristic values ​​reflecting the differences in voltage imbalance changes at different times in the power system are calculated.

[0033] Specifically, in this embodiment, the voltage imbalance degrees obtained at each time point and all previous time points are sorted in chronological order. The trend statistics and coefficient of variation of the sorted sequence are statistically analyzed, and the product of the trend statistics and coefficient of variation is used as the voltage imbalance degree change coefficient at each time point. The average of the voltage imbalance degree change coefficient at each time point and the corresponding cumulative change coefficient of balance deviation is used as the first characteristic coefficient of the voltage imbalance change difference at each time point. The larger the characteristic coefficient, the more significant the voltage imbalance variation characteristics at the current moment are, based on the comprehensive analysis of the three-phase parameter deviation characteristics and the change characteristics of the negative sequence component at different time periods during the operation of the power system.

[0034] Furthermore, the absolute value of the Pearson correlation coefficient between the instantaneous deviation characteristic value of voltage balance and the voltage imbalance degree at each time point and all previous times is calculated. In this embodiment, the absolute value is used as the second characteristic coefficient for the voltage imbalance characteristic analysis at each time point. The larger the second characteristic coefficient, the greater the correlation between the change characteristics of the three-phase voltage imbalance stage in the power system and the change characteristics of the resulting negative sequence component. This indicates a greater impact of the voltage imbalance on compensation based on the droop control strategy at the corresponding time. Based on the above characteristic analysis of voltage imbalance, the characteristic values ​​reflecting the differences in voltage imbalance changes at different times in the power system are calculated, and the calculation formula is as follows: ;in, Indicates the first Characteristic values ​​of voltage imbalance changes at each moment; and They represent the first The first and second characteristic coefficients correspond to each time point. It can be understood that the larger the calculated characteristic value, the greater the impact of the phased effects of imbalance disturbance differences during power system operation monitoring on voltage imbalance suppression.

[0035] Furthermore, the mean of the normalized results of all voltage imbalance change difference characteristic values ​​obtained up to the start time of the negative sequence voltage imbalance suppression treatment is used as the adjustment coefficient of the compensation response of the distribution network voltage imbalance suppression treatment. The larger the adjustment coefficient, the greater the impact of the difference in the phased imbalance deviation that causes the current voltage imbalance to exceed the limit on the compensation adjustment.

[0036] Based on the above analysis, during the operation of the power system, if the load voltage at a node gradually increases, it may lead to insufficient compensation response for voltage imbalance suppression at the current moment. Moreover, as the load ratio imbalance changes, under the influence of phased imbalance deviations, the power system's compensation response to voltage imbalance at nodes may be untimely, affecting the suppression of voltage imbalance. Therefore, in order to improve the suppression effect of voltage imbalance and enhance the speed of compensation response to changes in imbalance deviations, a relatively small droop coefficient should be set. That is, the larger the adjustment coefficient, the greater the impact on compensation adjustment. The droop coefficient should be adjusted to a smaller value to improve the response to compensation and reduce compensation lag time.

[0037] Step 3: Adjust the droop coefficient of the droop control strategy according to the adjustment coefficient, and then obtain the droop control function for negative sequence reactive power compensation of the distribution network, so as to suppress the negative sequence voltage imbalance of the distribution network.

[0038] Based on the analysis results of the above process regarding the characteristics of voltage imbalance in the distribution network, the voltage imbalance suppression process based on the droop strategy is dynamically optimized and adjusted. Specifically, the droop control parameters are dynamically adjusted based on the impact characteristics of the differences in the stage-specific imbalance deviations that cause the voltage imbalance to exceed the limit at the current moment on the compensation adjustment. First, in this embodiment, for voltage imbalance suppression during distribution network operation and maintenance, the droop coefficient in the droop control strategy is determined, and its relationship is as follows: ;in, Indicates the droop coefficient; and These represent the maximum power change and the maximum effective voltage change under steady-state operation of the distribution network, respectively. In this embodiment, the maximum effective voltage change is the difference between the maximum and minimum effective values ​​of the negative sequence component voltage obtained under steady-state operation of the distribution network. This represents the adjustment coefficient for the compensation response to suppress voltage imbalance in the distribution network. The larger the adjustment coefficient, the greater the difference in the dynamic characteristics of the monitoring data under the influence of imbalance at different stages. Therefore, a relatively small droop coefficient needs to be set to ensure timely compensation response.

[0039] Furthermore, based on the droop coefficient for suppressing voltage imbalance in the distribution network, the droop control function for negative-sequence reactive power compensation in the distribution network is analyzed. The specific calculation formula is as follows: ;in, Indicates a reference value for reactive power compensation; The reactive power reference value is indicated. Preferably, in this embodiment, the average reactive power under steady-state operation of the distribution network is used as the reactive power reference value. This represents the effective value of the negative sequence component voltage obtained at the current moment. The reference value for voltage is selected according to the rated voltage at the location of the power system monitoring point; This represents the droop coefficient.

[0040] The obtained reactive power compensation reference value is used as the target command for reactive power compensation in the static var generator. According to the target command, the reactive power compensation amount corresponding to the target command is output through the IGBT module of the STATCOM (static var generator). Then, the negative sequence voltage imbalance is suppressed by using the droop control strategy through the reactive power compensation amount. The specific process is existing technology, and no special restrictions are imposed on it in this embodiment.

[0041] Based on the same inventive concept as the above method, this application embodiment also provides a voltage imbalance suppression device for distribution network operation and maintenance, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of any one of the above-described voltage imbalance suppression methods for distribution network operation and maintenance.

[0042] Meanwhile, this application also provides a voltage imbalance suppression device for distribution network operation and maintenance. The device stores a computer program, which, when executed by a processor, implements any one of the voltage imbalance suppression methods for distribution network operation and maintenance described above.

[0043] It is understood that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0044] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0045] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the protection scope of this application.

Claims

1. A method for suppressing voltage imbalance in distribution network operation and maintenance, characterized in that, Includes the following steps: The three-phase phase voltage, three-phase line current, active power and reactive power at each monitoring point of the distribution network are obtained, and the negative sequence voltage imbalance at each monitoring point is calculated to determine whether it exceeds the limit. Suppression measures are implemented to address situations where negative sequence voltage imbalance exceeds the limit, specifically including: Based on the degree of difference in phase voltage at each time and the power distribution deviation of different phases at each time, the instantaneous deviation characteristic value of voltage balance at each time is obtained; based on the changing trend and dispersion of the instantaneous deviation characteristic value of voltage balance and the voltage unbalance, and combined with the correlation between the instantaneous deviation characteristic value of voltage balance and the voltage unbalance, the difference characteristic value of voltage imbalance at each time is obtained; and the adjustment coefficient of the voltage unbalance suppression and compensation response of the distribution network is obtained by the average level of the difference characteristic value of voltage imbalance. The droop coefficient of the droop control strategy is adjusted according to the adjustment coefficient, and then the droop control function for negative sequence reactive power compensation of the distribution network is obtained to suppress the negative sequence voltage imbalance of the distribution network. The average of the absolute values ​​of the differences between the phase voltage of each phase and the phase voltage of other phases at each time moment is taken. The ratio of this average value to the phase voltage of each phase is taken as the first characteristic value of the phase voltage balance deviation at each time moment. The ratio of the reactive power of each phase to the sum of the reactive power of all phases and the ratio of the useful power of each phase to the sum of the active power of all phases are calculated at each time moment. The average of the two ratios is taken as the second characteristic value of the phase voltage balance deviation at each time moment. The acquisition of the instantaneous voltage balance deviation characteristic values ​​at each moment is further as follows: ,in Indicates the first The characteristic value of the instantaneous deviation of voltage balance at each moment; and They represent the first At the [time]th moment The first and second characteristic values ​​of the phase voltage balance deviation; The voltage imbalance degree and voltage balance instantaneous deviation characteristic values ​​at each time point and all previous time points are sorted in chronological order. The trend statistics and coefficient of variation of the two sorted sequences are calculated. The product of the trend statistics and coefficient of variation corresponding to the voltage imbalance degree is used as the voltage imbalance degree change coefficient at each time point. The product of the trend statistics and coefficient of variation corresponding to the voltage balance instantaneous deviation characteristic value is used as the balance deviation cumulative change coefficient at each time point. The mean of the voltage imbalance change coefficient and the balance deviation cumulative change coefficient is used as the first characteristic coefficient of the voltage imbalance change difference at each time point. The acquisition of characteristic values ​​of voltage imbalance changes at different times is further as follows: ;in, Indicates the first Characteristic values ​​of voltage imbalance changes at each moment; and They represent the first The first and second characteristic coefficients corresponding to each time point are defined as follows: the absolute value of the Pearson correlation coefficient between the voltage balance instantaneous deviation characteristic value and the voltage unbalance degree at each time point and all previous time points is used as the second characteristic coefficient corresponding to each time point.

2. The voltage imbalance suppression method for distribution network operation and maintenance as described in claim 1, characterized in that, The mean of the normalized results of all voltage imbalance change difference characteristic values ​​obtained up to the start time of the negative sequence voltage imbalance suppression treatment is used as the adjustment coefficient of the compensation response of the distribution network voltage imbalance suppression treatment.

3. The voltage imbalance suppression method for distribution network operation and maintenance as described in claim 1, characterized in that, The adjustment coefficient for the compensation response to suppress voltage imbalance in the distribution network is further obtained as follows: ;in, Indicates the droop coefficient; and These represent the maximum power change and the maximum effective voltage change under steady-state operation of the distribution network, respectively. For the three-phase phase voltage, the Clark transformation and dual synchronous rotating coordinate transformation are used to obtain the corresponding negative sequence component and positive sequence component, and the effective value of the negative sequence component voltage is statistically analyzed. The maximum effective voltage change is the difference between the maximum and minimum effective values ​​of the negative sequence component voltage obtained under steady-state operation of the distribution network. This represents the adjustment coefficient for the compensation response to suppress voltage imbalance in the distribution network.

4. The voltage imbalance suppression method for distribution network operation and maintenance as described in claim 3, characterized in that, The droop control function for obtaining the negative sequence reactive power compensation of the distribution network includes: ;in, Indicates a reference value for reactive power compensation; This represents the baseline value for reactive power. Indicates a reference value for voltage. Indicates the droop coefficient. This represents the effective value of the negative sequence component voltage obtained at the current moment.

5. A voltage imbalance suppression device for distribution network operation and maintenance, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the voltage imbalance suppression method for distribution network operation and maintenance as described in any one of claims 1-4.

6. A voltage imbalance suppression device for distribution network operation and maintenance, wherein the device stores a computer program, characterized in that, When the computer program is executed by the processor, it implements a voltage imbalance suppression method for distribution network operation and maintenance as described in any one of claims 1-4.

Images