Voltage unbalance suppression method, equipment and device for operation and maintenance of power distribution network

Abstract

The invention relates to the technical field of power distribution systems, in particular to a voltage unbalance degree suppression method, equipment and device for operation and maintenance of a power distribution network, and the method comprises the steps: obtaining three-phase phase voltage, three-phase line current, active power and reactive power at each monitoring point of the power distribution network, carrying out the statistics of the negative sequence voltage unbalance degree of each monitoring point, and judging whether the negative sequence voltage unbalance degree exceeds a limiting value or not; obtaining a voltage balance instantaneous deviation characteristic value to obtain a voltage unbalance change difference characteristic value, and further obtaining an adjustment coefficient of a power distribution network voltage unbalance degree suppression processing compensation response; and adjusting a droop coefficient of a droop control strategy according to the adjustment coefficient, and further obtaining a droop control function of negative-sequence reactive power compensation of the power distribution network so as to suppress the negative-sequence voltage unbalance degree of the power distribution network. The suppression effect of the voltage unbalance degree of the power distribution network can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power distribution systems, in particular to a voltage unbalance degree suppression method, device and apparatus for power distribution network operation and maintenance. BACKGROUND

[0002] If the voltage unbalance degree exceeds the safety threshold range during the operation of the power distribution network, the operation efficiency of the three-phase asynchronous motor will decrease, the motor will overheat seriously, and the stable operation of the asynchronous motor will be affected. For precise electronic equipment, if the three-phase voltage is asymmetric, the electronic equipment may operate abnormally, and the electronic equipment may be damaged. In addition, voltage imbalance during the operation of the power distribution network will increase the line loss. Therefore, effectively suppressing the voltage unbalance degree during the operation of the power distribution network can guarantee the power supply quality of the user end in the power system, improve the operation efficiency of the power distribution network, and maintain the safe and stable operation of the power system.

[0003] However, during the operation of the power distribution network, the voltage imbalance state is caused by the influence of load changes, and the adjustment effect of the actual voltage imbalance state is poor due to the influence of various interference factors during the voltage imbalance suppression process. The droop control method is a common method for suppressing the voltage unbalance degree of the power distribution network. Combined with the droop control characteristics, the voltage imbalance state of the power distribution network during operation can be effectively suppressed. However, due to the differences in load characteristics, line impedance and system operation state characteristics of the power distribution network, if the droop coefficient deviates greatly during the droop control process, insufficient compensation or excessive compensation will occur, which will aggravate the voltage fluctuation of the power distribution network and cannot meet the suppression requirements of the voltage unbalance degree of the power distribution network under the state characteristic differences caused by multiple interference factors, resulting in poor stability of the power distribution network during operation. SUMMARY

[0004] To solve the above technical problems, the purpose of the present application is to provide a voltage unbalance degree suppression method, device and apparatus for power distribution network operation and maintenance, and the technical solutions adopted are as follows: In a first aspect, the present application provides a voltage unbalance degree suppression method for power distribution network operation and maintenance, comprising the following steps: Obtain the three-phase phase voltage, three-phase line current, active power and reactive power at each monitoring point of the power distribution network, and count the negative sequence voltage unbalance degree of each monitoring point to determine whether it exceeds the limit value; For the case where the negative sequence voltage unbalance degree exceeds the limit value, suppression processing is performed, specifically including: According to the difference degree of different phase voltages at each moment and the power distribution deviation of different phases at each moment, voltage balance instantaneous deviation characteristic values at each moment are obtained; according to the voltage balance instantaneous deviation characteristic values and the change trend and dispersion of the voltage unbalance degree, and in combination with the correlation between the voltage balance instantaneous deviation characteristic values and the voltage unbalance degree, voltage imbalance change difference characteristic values at each moment are obtained, and the regulation coefficient of the power distribution network voltage unbalance degree suppression processing compensation response is obtained through the average level of the voltage imbalance change difference characteristic values; According to the regulation coefficient, the droop coefficient of the droop control strategy is adjusted, and then a droop control function of the power distribution network negative sequence reactive power compensation is obtained to suppress the negative sequence voltage unbalance degree of the power distribution network.

[0005] Preferably, the mean value of the absolute value of the difference between each phase voltage and the voltage of other phases at each moment is calculated, and the ratio of the mean value to each phase voltage is taken as the first characteristic value of the voltage balance deviation of each phase at each moment, and the ratio of each phase reactive power to the sum of all phase reactive powers and the ratio of each phase active power to the sum of all phase active powers are calculated, and the mean value of the two ratios is taken as the second characteristic value of the voltage balance deviation of each phase at each moment.

[0006] Preferably, the voltage balance instantaneous deviation characteristic values at each moment are further obtained as follows: , wherein represents the voltage balance instantaneous deviation characteristic value at the i th moment; and respectively represent the first characteristic value and the second characteristic value of the voltage balance deviation of the j th phase at the i th moment.

[0007] Preferably, the voltage unbalance degrees and the voltage balance instantaneous deviation characteristic values at each moment and all moments before the moment are sorted in time sequence respectively, and the trend statistic and the coefficient of variation of the two sequences after sorting are calculated, the product of the trend statistic and the coefficient of variation corresponding to the voltage unbalance degree is taken as the voltage unbalance change coefficient at each moment, the product of the trend statistic and the coefficient of variation corresponding to the voltage balance instantaneous deviation characteristic value is taken as the balance deviation cumulative change coefficient at each moment, and the mean value of the voltage unbalance change coefficient and the balance deviation cumulative change coefficient is taken as the first characteristic coefficient of the voltage imbalance change difference at each moment.

[0008] Preferably, the voltage imbalance change difference characteristic values at each moment are further obtained as follows: , wherein represents the voltage imbalance change difference characteristic value at the i th moment; and​​​​ respectively represent the first and second characteristic coefficients corresponding to the i-th moment, wherein the absolute value of the Pearson correlation coefficient between the voltage balance transient deviation characteristic value and the voltage unbalance degree of each moment and all moments before it is taken as the second characteristic coefficient corresponding to each moment.

[0009] Preferably, the mean of the normalized processing results of all voltage imbalance change difference characteristic values obtained before the moment when the negative sequence voltage unbalance suppression processing is started is taken as the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response.

[0010] Preferably, the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response is further obtained as follows: , wherein, represents the droop coefficient; and respectively represent the maximum power change and the maximum voltage effective value change under steady-state operation of the power distribution network, wherein the corresponding negative sequence component and positive sequence component are obtained by using Clark transformation and double synchronous rotating coordinate transformation on the three-phase phase voltage, and the effective value of the negative sequence component voltage is counted, and the maximum voltage effective value change is the difference between the maximum and minimum values of the effective value of the negative sequence component voltage obtained under steady-state operation of the power distribution network. represents the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response.

[0011] Preferably, the further obtaining of the droop control function of the power distribution network negative sequence reactive power compensation comprises: , wherein, represents the reference value of the reactive power compensation; represents the reference value of the reactive power, represents the reference value of the voltage, represents the droop coefficient, represents the effective value of the negative sequence component voltage obtained at the current moment.

[0012] In a second aspect, the embodiments of the present application also provide a voltage unbalance degree suppression device for power distribution network operation and maintenance, which comprises a memory, a processor, and a computer program stored in the memory and running on the processor, and the processor implements the steps of the voltage unbalance degree suppression method for power distribution network operation and maintenance according to any one of the above embodiments when executing the computer program.

[0013] In a third aspect, the embodiments of the present application also provide a voltage unbalance degree suppression device for power distribution network operation and maintenance, which stores a computer program, and the computer program is executed by a processor to implement the voltage unbalance degree suppression method for power distribution network operation and maintenance according to any one of the above embodiments.​

[0014] From the above, the power distribution network operation and maintenance voltage imbalance degree suppression method, device and apparatus provided by the application has at least the following beneficial effects: The application considers that, in the process of power distribution network operation and maintenance, due to large differences in load ratio changes at different stages, the response difference is large in the process of voltage imbalance compensation processing, thereby the phenomena of insufficient compensation or excessive compensation occur, which affects the suppression effect of voltage imbalance, therefore, the application collects monitoring data at the key nodes of the power system, and calculates the negative sequence voltage imbalance degree based on the collected monitoring data, to judge whether the power imbalance state is out of limit, so as to compensate and adjust the power imbalance state of the power system; Further, the application accurately analyzes the voltage imbalance characteristics of the power distribution network based on the collected monitoring data at the nodes and the balance deviation caused by the load ratio changes at different stages, and dynamically adjusts the droop control coefficient through the analysis result, to realize accurate compensation of voltage imbalance, which has the beneficial effect of fully combining the balance deviation difference of the power system at different stages under the voltage imbalance state, accurately compensating and adjusting the voltage imbalance degree of the power system, and improving the voltage imbalance degree suppression effect of the power distribution network operation and maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0016] Figure 1 The step flowchart of the power distribution network operation and maintenance voltage imbalance degree suppression method provided by the application; Figure 2 The acquisition flowchart of the voltage balance instantaneous deviation characteristic value at each moment provided by the embodiment of the application. DETAILED DESCRIPTION

[0017] In order to further illustrate the technical means and effects adopted by the application to achieve the predetermined invention purpose, the following describes the power distribution network operation and maintenance voltage imbalance degree suppression method, device and apparatus according to the application, its specific implementation, structure, characteristics and effects in detail, as follows. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0018] Unless otherwise defined, all terms (including 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 belongs. It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

[0019] Specifically, the power distribution network operation and maintenance voltage unbalance degree suppression method, device and apparatus provided by the present application are described below in combination with the accompanying drawings.

[0020] Referring to Figure 1 , a step flow chart of a power distribution network operation and maintenance voltage unbalance degree suppression method provided by an embodiment of the present application is shown, including the following steps: Step one: acquiring three-phase phase voltages, three-phase line currents, active power and reactive power at each monitoring point of the power distribution network, and counting the negative sequence voltage unbalance degree of each monitoring point to determine whether it exceeds the limit value.

[0021] In the process of power distribution network voltage unbalance degree suppression, the voltage balance state of the power distribution network needs to be monitored and judged first, and the voltage imbalance is suppressed accordingly based on the monitoring and judgment results. Specifically, monitoring points are set at each key node of the power distribution network, and smart meters are installed at each monitoring point to collect three-phase phase voltages , three-phase line currents , active power (P) and reactive power (Q) at the monitoring points, wherein, are the phase voltages of the a, b and c phases respectively, are the line currents of the a, b and c phases respectively; in this embodiment, the key nodes include the low-voltage side outlet position of the power distribution network transformer, the feeder section switch position and the distributed power key-in point position, and the time interval for collecting data is 1s.

[0022] Due to the complex operation environment of the power distribution network, there are many environmental noise and electromagnetic noise interference in the process of data collection and transmission, which leads to poor data quality. Therefore, in this embodiment, a wavelet threshold denoising algorithm is used to process the collected data to reduce the influence of high-frequency interference noise on the quality of the collected power distribution network monitoring data. After denoising, the data is detected and processed for abnormal data by the Laplace criterion to avoid the influence of abnormal deviation data on the accuracy of the power distribution network operation state judgment. The specific wavelet threshold denoising algorithm and the process of abnormal detection and processing based on the Laplace criterion are known to those skilled in the art and will not be described in detail.

[0023] Based on the preprocessed data, the voltage unbalance degree of each monitoring point at each time is calculated, and the voltage instability state of the power distribution network is judged based on the calculation result. It should be noted that the analysis and calculation process of the voltage unbalance degree is a known technology to those skilled in the art. Specifically, in this embodiment, according to the standard of GB / T15543-2008, the voltage unbalance degree is calculated by the symmetrical component algorithm. For each monitoring point, the collected As input, the corresponding negative sequence component and positive sequence component are obtained by Clark transformation and double synchronous rotating coordinate transformation, and the effective value of the corresponding negative sequence component and positive sequence component is calculated and the effective value of the positive sequence component The corresponding negative sequence voltage unbalance degree is: According to the provisions of GB / T 15543-2008 "Power Quality Three-Phase Voltage Unbalance", the negative sequence voltage unbalance degree of the monitoring point does not exceed the limit value of 2% during the operation of the power system, and the short-time negative sequence voltage unbalance degree does not exceed the limit value of 4%. The short-time negative sequence voltage unbalance degree refers to the peak value of the monitoring and calculation result within 1 min. Based on the above provisions, the voltage unbalance degree state of each monitoring point is monitored and judged. If the calculated negative sequence voltage balance degree of the current monitoring point exceeds the above limit value, the power distribution network voltage unbalance degree suppression processing is started.

[0024] Step two: According to the difference degree of different phase voltages at each time and the power distribution deviation of different phases at each time, the voltage balance instantaneous deviation characteristic value at each time is obtained; according to the change trend and dispersion of the voltage balance instantaneous deviation characteristic value and the voltage unbalance degree, and combined with the correlation between the voltage balance instantaneous deviation characteristic value and the voltage unbalance degree, the voltage imbalance change difference characteristic value at each time is obtained, and the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response is obtained by the average level of the voltage imbalance change difference characteristic value.

[0025] In the process of power system operation, if the negative sequence voltage imbalance degree monitored and judged exceeds the limit value, the corresponding voltage imbalance suppression processing program is started for suppression processing. However, due to the complexity of the causes of voltage imbalance in the power distribution network, the difference in various interference effects may lead to insufficient compensation or lagging compensation in the actual suppression process, thereby leading to poor voltage imbalance suppression effect of the power distribution network and unstable operation of the power system.

[0026] Therefore, based on the judgment result of the node voltage imbalance state in the process of power system operation, the monitoring data of the power grid collected at the time of starting voltage imbalance suppression processing is analyzed for dynamic change characteristics, and the compensation in the actual suppression process is dynamically adjusted in combination with the dynamic characteristic difference of the monitoring data caused by the difference in different interference effects, thereby improving the suppression effect of the voltage imbalance state of the power distribution network. The specific analysis and processing process of the voltage imbalance characteristics of the power distribution network in the process of power distribution network operation is as follows: First, considering the complex influence characteristics of voltage imbalance in the process of power system operation, the dynamic change characteristics of the node parameters in the power distribution network at different stages are quite different, which affects the compensation processing effect of the power imbalance. Therefore, for each kind of monitoring data collected at the current voltage imbalance time for each monitoring point, including three-phase phase voltage, three-phase line current, active power and reactive power, each kind of monitoring data is normalized, and the time sequence change difference between different phases in the monitoring process is analyzed based on the processing result. It should be noted that there are many existing normalization processing methods, and the implementer can select them as needed. The present embodiment does not make special limitations, and the maximum normalization method is used in the present embodiment. The specific process is a prior art, which is not described here.

[0027] Specifically, for the processed three-phase voltage data, the mean value of the absolute value of the difference between each phase voltage and other phase voltage at each time is calculated, and the ratio of the mean value to each phase voltage is taken as the first characteristic value of the balance deviation of each phase voltage at each time The larger the first characteristic value is, the greater the parameter fluctuation caused by single-phase load change in the actual processing process is. Further, considering the unbalanced load ratio of different phases under the voltage imbalance state, the actual power distribution ratio deviates greatly, therefore, the mean value of the ratio of each phase reactive power to the sum of all phase reactive power and the ratio of each phase active power to the sum of all phase active power is calculated, and the mean value of the two ratios is taken as the second characteristic value of the balance deviation of each phase voltage at each time The larger the second characteristic value is, the greater the instantaneous power difference under the unbalanced load ratio.

[0028] Based on the above analysis, the instantaneous characteristics of the balance deviation of each phase voltage at each moment in the monitoring process are comprehensively analyzed, and the instantaneous balance deviation characteristic value of each moment voltage balance is obtained according to the first characteristic value and the second characteristic value of the balance deviation of each phase voltage at each moment, and the calculation relationship is: wherein represents the instantaneous balance deviation characteristic value of the voltage at the m-th moment; and respectively represent the first characteristic value and the second characteristic value of the balance deviation of the n-th phase voltage at the m-th moment, that is The greater the value is, the more significant the characteristic of the change difference of the single-phase balance instantaneous deviation caused by the unbalanced load ratio of the power grid is.

[0029] Specifically, the acquisition process of the instantaneous balance deviation characteristic value of each moment is shown in the flowchart as shown in Figure 2 .

[0030] Further, the voltage balance instantaneous deviation characteristic values corresponding to each moment and all moments before it are sorted in time sequence, and the trend statistic and the coefficient of variation of the sorted sequence are calculated. It should be noted that the trend statistic of the sequence is obtained by the MK trend check algorithm in this embodiment, and the specific process of obtaining the trend statistic by the MK trend check algorithm is a prior art, which is not specially limited in this embodiment, and will not be described here. At the same time, the calculation process of the coefficient of variation is a prior art known to those skilled in the art, and the specific calculation process will not be described in this embodiment. The product of the trend statistic and the coefficient of variation of each moment is taken as the balance deviation cumulative change coefficient of each moment, which represents the balance deviation cumulative change difference characteristic of the power system at different stages.

[0031] Based on the above analysis, in the operation and maintenance process of the distribution network, the instantaneous characteristics of three-phase voltage and active and reactive power of different nodes are analyzed in combination with the characteristic difference of the interference affecting the voltage imbalance, and the balance instantaneous deviation change difference of each moment is accurately analyzed by comprehensively considering the difference of the unbalanced load ratio change of each phase, and further the cumulative deviation characteristic of the power system node at different stages is extracted, reflecting the staged balance state change difference characteristic.

[0032] ​​​Further, since the voltage imbalance of the power distribution network is compensated by the droop control strategy, the imbalance suppression is mainly achieved by adjusting the reactive power. The load ratio imbalance state characteristics are different in different stages of the operation process, the negative sequence voltage changes are different, the stage cumulative change characteristics of the voltage imbalance degree are different, and the adjustment difference of the balance compensation of the droop control is greater. Therefore, by combining the stage change characteristics of the voltage imbalance degree and the stage difference characteristics of the balance state in the operation process of the power system, the stage change characteristics of the voltage imbalance state are accurately analyzed, and the voltage imbalance change difference characteristic values of the power system at different times are calculated.

[0033] Specifically, in the embodiment, the voltage imbalance degrees at each time and all times before the each time are sorted in time sequence, the trend statistic and the coefficient of variation of the sorted sequence are counted, and the product of the trend statistic and the coefficient of variation is taken as the voltage imbalance degree change coefficient at each time. The average of the voltage imbalance degree change coefficient at each time and the corresponding balance deviation cumulative change coefficient is taken as the first characteristic coefficient of the voltage imbalance change difference at each time The greater the characteristic coefficient is, the more significant the voltage imbalance change difference characteristic at the current time is, which is analyzed by combining the three-phase parameter deviation characteristics and the change characteristics of the negative sequence component in different time periods in the operation process of the power system.

[0034] Further, the absolute value of the Pearson correlation coefficient between the voltage balance instantaneous deviation characteristic value at each time and all times before the each time and the voltage imbalance degree is calculated, which is taken as the second characteristic coefficient of the voltage imbalance characteristic analysis at each time in the embodiment The greater the second characteristic coefficient is, the greater the influence of the voltage imbalance at the corresponding time on the compensation based on the droop control strategy is, which is analyzed by combining the change characteristics of the three-phase voltage imbalance stage and the change characteristics of the negative sequence component caused thereby. The voltage imbalance change difference characteristic values of the power system at different times are calculated based on the above-mentioned voltage imbalance characteristic analysis, and the calculation relationship is: ; wherein, represents the voltage imbalance change difference characteristic value at the th time; and respectively represent the first characteristic coefficient and the second characteristic coefficient corresponding to the th time. It can be understood that the greater the calculated characteristic value is, the greater the influence of the stage influence of the imbalance interference difference caused in the operation monitoring process of the power system on the voltage imbalance suppression is.

[0035] Further, the mean of the normalization processing results of all voltage imbalance change difference characteristic values obtained before the moment when the negative sequence voltage imbalance suppression processing is started is taken as the adjustment coefficient of the power distribution network voltage imbalance degree suppression processing compensation response The greater the adjustment coefficient is, that is, the greater the influence of the corresponding phase imbalance deviation change difference that causes the current moment voltage imbalance to exceed the limit on compensation adjustment is.

[0036] Based on the above analysis, during the operation of the power system, if the node load voltage gradually increases, it may lead to insufficient compensation response of the voltage imbalance suppression processing at the current moment, and with the imbalance change of the load ratio, the power system may not respond in time to the voltage imbalance of the node under the influence of the phase imbalance deviation, affecting the suppression processing of the voltage imbalance degree. Therefore, to improve the suppression effect of the voltage imbalance degree and improve the speed of the compensation response to the imbalance deviation change difference, a relatively small droop coefficient is set, that is, the greater the adjustment coefficient is, the greater the influence on compensation adjustment is, and the droop coefficient is adjusted to a smaller value to improve the response to the compensation amount and reduce the compensation lag time.

[0037] Step three: adjusting the droop coefficient of the droop control strategy according to the adjustment coefficient, and then obtaining the droop control function of the power distribution network negative sequence reactive power compensation to suppress the negative sequence voltage imbalance degree of the power distribution network.

[0038] Based on the analysis results of the voltage imbalance characteristics of the power distribution network, the process of suppressing the voltage imbalance of the power distribution network based on the droop strategy is dynamically optimized and adjusted. Specifically, the droop control parameters are dynamically adjusted based on the influence characteristics of the phase imbalance deviation change difference that causes the current moment voltage imbalance to exceed the limit on compensation adjustment. First, in this embodiment, the droop coefficient in the droop control strategy is determined for suppressing the voltage imbalance degree during the operation of the power distribution network, and the relationship is determined as follows: ; wherein, represents the droop coefficient; and respectively represent the maximum power change and the maximum voltage effective value change under the steady-state operation of the power distribution network, wherein in this embodiment, the maximum voltage effective value change is the difference between the maximum value and the minimum value of the effective value of the negative sequence component voltage obtained under the steady-state operation of the power distribution network. represents the adjustment coefficient of the power distribution network voltage imbalance degree suppression processing compensation response, and the greater the adjustment coefficient is, the greater the imbalance deviation change difference of the dynamic characteristics of the monitoring data at different stages under the influence of the imbalance is, and a relatively small droop coefficient needs to be set to respond in time.

[0039] Further, based on the droop coefficient of the voltage imbalance suppression of the power distribution network, the droop control function of the negative sequence reactive power compensation of the power distribution network is analyzed, and the specific calculation relationship is as follows: ; wherein, represents the reference value of the reactive power compensation; represents the reference value of the reactive power, and preferably, the average value of the reactive power in the steady operation of the power distribution network is taken as the reference value of the reactive power in the embodiment; represents the effective value of the negative sequence component voltage obtained at the current moment, represents the reference value of the voltage, which is selected according to the rated voltage of the position of the monitoring point of the power system; represents the droop coefficient.

[0040] The obtained reference value of the reactive power compensation is taken as the target instruction of the reactive power compensation in the static reactive power generator, and the IGBT module of the STATCOM (static reactive power generator) outputs the reactive power compensation amount corresponding to the target instruction according to the target instruction, and then the reactive power compensation amount is used to suppress the negative sequence voltage imbalance degree by using the droop control strategy. The specific process is the prior art, and the embodiment is not specially limited.

[0041] Based on the same inventive concept as the above method, the embodiment of the present application also provides a voltage imbalance suppression device for power distribution network operation and maintenance, which comprises a memory, a processor and a computer program stored in the memory and running on the processor. The processor executes the computer program to realize the steps of any one of the above-mentioned methods for voltage imbalance suppression of power distribution network operation and maintenance.

[0042] Meanwhile, the embodiment of the present application also provides a voltage imbalance suppression device for power distribution network operation and maintenance, which stores a computer program. The computer program is executed by the processor to realize any one of the above-mentioned methods for voltage imbalance suppression of power distribution network operation and maintenance.

[0043] It can be understood that the above-mentioned sequence of the embodiments of the present application is only for description, and does not represent the advantages and disadvantages of the embodiments. And the above describes the specific embodiments of the present application. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multi-task processing and parallel processing are possible or may be advantageous.

[0044] Each embodiment in the present specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other. Each embodiment focuses on the difference from other embodiments.

[0045] The above merely illustrates the embodiments of the present application, and is not intended to limit the scope of the present application, and any equivalent structure or equivalent process transformation, or direct or indirect application in other related technical fields, which are made by using the content of the present application specification and drawings, are also included in the protection scope of the present application.

Claims

1. A method for suppressing voltage unbalance degree in power distribution network operation and maintenance, characterized in that, The method comprises the following steps: obtaining three-phase phase voltages, three-phase line currents, active power and reactive power at each monitoring point of the power distribution network, and counting the negative sequence voltage unbalance degree of each monitoring point to determine whether it exceeds the limit value; for the case that the negative sequence voltage unbalance degree exceeds the limit value, the suppression processing is carried out, specifically including: According to the difference degree of different phase voltages at each moment and the power distribution deviation of different phases at each moment, the voltage balance instantaneous deviation characteristic value at each moment is obtained; according to the change trend and dispersion of the voltage balance instantaneous deviation characteristic value and the voltage unbalance degree, and combining the correlation between the voltage balance instantaneous deviation characteristic value and the voltage unbalance degree, the voltage imbalance change difference characteristic value at each moment is obtained, and the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response is obtained through the average level of the voltage imbalance change difference characteristic value; According to the adjustment coefficient, the droop coefficient of the droop control strategy is adjusted, and then the droop control function of the negative sequence reactive power compensation of the power distribution network is obtained to suppress the negative sequence voltage unbalance degree of the power distribution network.

2. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 1, characterized in that, The average value of the absolute value of the difference between each phase voltage and other phase voltages at each moment is calculated, and the ratio of the average value to each phase voltage is taken as the first characteristic value of the voltage balance deviation of each phase at each moment. The ratio of each phase reactive power to the sum of all phase reactive power, and the ratio of each phase active power to the sum of all phase active power are calculated respectively, and the average value of the two ratios is taken as the second characteristic value of the voltage balance deviation of each phase at each moment.

3. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 2, characterized in that, The acquisition of the voltage balance instantaneous deviation characteristic value at each moment is further: wherein denotes the instantaneous deviation eigenvalue of the voltage balance at the and denote the first and second eigenvalue of the voltage balance deviation of the phase at the time instant, respectively.

4. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 1, characterized in that, The voltage unbalance degree and the voltage balance instantaneous deviation characteristic value at each moment and all moments before it are sorted in time sequence respectively, and the trend statistics and the coefficient of variation of the two sequences after sorting are counted respectively. The product of the trend statistics and the coefficient of variation corresponding to the voltage unbalance degree is taken as the voltage unbalance degree change coefficient at each moment, and the product of the trend statistics and the coefficient of variation corresponding to the voltage balance instantaneous deviation characteristic value is taken as the balance deviation cumulative change coefficient at each moment. The average value of the voltage unbalance change coefficient and the balance deviation cumulative change coefficient is taken as the first characteristic coefficient of the voltage imbalance change difference at each moment.

5. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 4, characterized in that, The acquisition of the voltage imbalance change difference characteristic value at each moment is further: ;in, Indicates the The characteristic value of voltage imbalance change difference at each moment; and Respectively represent The first characteristic coefficient and the second characteristic coefficient corresponding to each moment are obtained, wherein the absolute value of the Pearson correlation coefficient between the voltage balance instantaneous deviation characteristic value and the voltage imbalance degree at each moment and all previous moments is used as the second characteristic coefficient corresponding to each moment.

6. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 1, characterized in that, The average value of the normalization processing results of all voltage imbalance change difference characteristic values obtained before the starting moment of the negative sequence voltage unbalance suppression processing is taken as the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response.

7. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 1, characterized in that, The acquisition of the adjustment coefficient of the power distribution network voltage unbalance degree suppression processing compensation response is further: ; wherein, represents a droop coefficient; and respectively represent the maximum power variation and the maximum voltage effective value variation under the steady-state operation of the power distribution network, wherein the corresponding negative sequence component and positive sequence component are obtained by using the Clark transformation and the double synchronous rotating coordinate transformation for the three-phase phase voltage, and the effective value of the negative sequence component voltage is counted, and the maximum voltage effective value variation is the difference between the maximum value and the minimum value of the effective value of the negative sequence component voltage obtained under the steady-state operation of the power distribution network; represents the adjustment coefficient of the compensation response of the voltage imbalance degree suppression processing.

8. The voltage unbalance degree suppression method for power distribution network operation and maintenance according to claim 7, characterized in that, The further acquisition of the droop control function of the negative sequence reactive power compensation of the power distribution network includes: ; wherein represents a reference value of the reactive power compensation; represents a reference value of the reactive power, represents a reference value of the voltage, represents a droop coefficient, represents a value of the effective value of the negative sequence component voltage obtained at the current time.

9. A voltage unbalance degree suppression device for power 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, The processor executes the computer program to realize the steps of the voltage unbalance degree suppression method of the power distribution network operation and maintenance according to any one of claims 1-8.

10. A voltage unbalance degree suppression device for power distribution network operation and maintenance, a computer program is stored in the device, characterized in that, The computer program is executed by the processor to realize the voltage unbalance degree suppression method of the power distribution network operation and maintenance according to any one of claims 1-8.

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