A risk identification method for voltage fluctuations in distribution networks containing distributed energy

Abstract

The present invention belongs to the technical field of power grid analysis. The present invention provides a method for identifying the risk of voltage fluctuation in a distribution network containing distributed energy, comprising: based on position analysis of a voltage change curve, generating an analysis signal, performing mutation analysis on the voltage change curve of a real-time operation of a power grid, obtaining a voltage change mutation value, judging the degree of voltage mutation risk of the distribution network according to the voltage change mutation value, acquiring power data of the distributed energy connected to the distribution network, performing correlation analysis on the power data and the voltage data of the distribution network, obtaining an impact correlation value, judging whether the output power change of the distributed energy will affect the fluctuation of the distribution network voltage according to the impact correlation value, realizing monitoring and identification of the risk of voltage mutation of the distribution network, and analyzing its influencing factors, which is conducive to subsequent rapid adjustment and optimization based on the influencing factors, and ensuring the safety of the operation of the distribution network.

Description

Technical Field

[0001] The invention belongs to the technical field of power grid analysis, and in particular to a method for identifying the risk of voltage fluctuations in a distribution network containing distributed energy. Background Art

[0002] As the environmental problems caused by traditional fossil energy become increasingly prominent, new energy sources, mainly solar energy and wind energy, have been deeply studied and widely used. While distributed new energy grid-connected power generation solves energy shortages and environmental pollution, its large-scale access also brings about problems such as voltage fluctuations in the distribution network and reduced power quality.

[0003] In the prior art, there is a lack of analysis of sudden voltage fluctuations in the distribution network and analysis of the causes of the sudden voltage fluctuations. As a result, after a sudden voltage fluctuation occurs in the distribution network, it is impossible to quickly and accurately find the cause of the voltage mutation, thereby failing to maintain the safe operation of the distribution network to the maximum extent. There is also a lack of effective investigation of the distributed energy of the distribution network based on the causes of the voltage mutation, resulting in the inability to timely optimize and adjust the distributed energy access to the distribution network.

[0004] To this end, the present invention provides a method for identifying the risk of voltage fluctuations in a distribution network containing distributed energy. Summary of the invention

[0005] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for identifying the risk of voltage fluctuation in a distribution network containing distributed energy, comprising:

[0007] Step 1: acquiring voltage data of the distribution network in real time, wherein the voltage data includes a voltage value, constructing a voltage change curve of the real-time operation of the distribution network based on the voltage data of the distribution network, and generating an operation signal based on a position analysis of the voltage change curve, wherein the operation signal includes an operation signal and an analysis signal;

[0008] Step 2: Based on the analysis signal, a mutation analysis is performed on the voltage change curve of the real-time operation of the power grid to obtain a voltage change mutation value, and the voltage mutation risk degree of the distribution network is determined according to the voltage change mutation value, and a risk signal is generated, wherein the risk signal includes a high risk signal and a low risk signal;

[0009] Step 3: Based on the generation of high-risk signals, the power data of the distributed energy connected to the distribution network is obtained, wherein the power data includes the output power. Based on the correlation analysis of the power data and the voltage data of the distribution network, the impact correlation value is obtained. According to the impact correlation value, it is determined whether the output power change of the distributed energy will affect the fluctuation of the distribution network voltage. If so, an impact signal is generated;

[0010] Step 4: Based on the generated impact signal and the power data of distributed energy, the change matching value is obtained through analysis and processing, and the troubleshooting path of distributed energy is determined based on the change matching value. The distributed energy is troubleshooted and analyzed based on the troubleshooting path of distributed energy, and the influence of distributed energy on the voltage fluctuation of its distribution network is evaluated.

[0011] As a further technical solution of the present invention, the voltage value obtained in real time is marked in an XY coordinate system, and the voltage value marking points are connected to obtain a voltage change curve, wherein the X axis represents time and the Y axis represents voltage value;

[0012] Take the voltage standard threshold as the reference value, mark it on the Y axis, draw a straight line parallel to the X axis through the reference value mark point, and mark it as the voltage threshold line;

[0013] There are two voltage threshold lines, including a first voltage threshold line and a second voltage threshold line, and the first voltage threshold line is located above the second voltage threshold line;

[0014] The area between the first voltage threshold line and the second voltage threshold line is the normal operating area, and the area outside the normal operating area is the mutation analysis area, including the first mutation analysis area and the second mutation analysis area, wherein the first mutation analysis area represents the area above the first threshold line, and the second mutation analysis area represents the area between the second threshold line and the X-axis;

[0015] Obtain the voltage change curve and perform position analysis on it, specifically:

[0016] If the end point of the voltage variation curve is within the normal operating area, an operating signal is generated;

[0017] If the end point of the voltage change curve is within the mutation analysis region, an analysis signal is generated.

[0018] As a further technical solution of the present invention, if the end point of the voltage change curve is within the first mutation analysis region, then the trough point in the voltage change curve that is closest to the end point of the voltage change curve in horizontal distance is obtained, and it is marked as the mutation starting point; if the end point of the voltage change curve is within the second mutation analysis region, then the peak point in the voltage change curve that is closest to the end point of the voltage change curve in horizontal distance is obtained, and it is marked as the mutation starting point; the mutation starting point and the end point of the voltage change curve are connected by a straight line to obtain a mutation line; at the same time, a vertical line is drawn through the end point line of the voltage change curve to the X-axis to obtain a maximum mutation reference line; the angle between the mutation line and the maximum mutation reference line is measured, and it is marked as the mutation angle; the mutation angle is ratio-processed with the right angle to obtain the mutation angle ratio;

[0019] The time points corresponding to the mutation starting point and the end point of the voltage change curve are obtained respectively, and difference processing is performed according to the time points to obtain the time difference between the mutation starting point and the end point of the voltage change curve, and the time difference is processed by ratio processing with the risk analysis period to obtain the mutation time ratio;

[0020] The obtained mutation angle ratio and mutation time ratio are processed by ratio processing to obtain the voltage change mutation value.

[0021] As a further technical solution of the present invention, the voltage change mutation value is compared with the voltage change mutation threshold;

[0022] If the voltage change mutation value is greater than the voltage change mutation threshold, a high-risk signal is generated;

[0023] If the voltage change mutation value is less than or equal to the voltage change mutation threshold, a low risk signal is generated.

[0024] As a further technical solution of the present invention, the output power of all distributed energy sources is obtained in real time, and the sum is averaged to obtain the real-time output power average of the distributed energy sources, and the real-time output power average of the distributed energy sources is marked and connected in an XY coordinate system to obtain a first output power change curve, wherein the X-axis represents time and the Y-axis represents output power;

[0025] The period between the time point corresponding to the end point of the voltage change curve and the start time point of the risk analysis cycle is marked as an impact analysis period, and the impact analysis period is divided into a number of time analysis nodes. The time analysis nodes are marked on the X-axis in the coordinate system where the first output power change curve and the voltage change curve are located according to the corresponding time points, and a straight line parallel to the Y-axis is made through the marked points of the time analysis nodes, and marked as a dividing line. The first output power change curve and the voltage change curve are divided by the dividing line, and part of the first output power change curve and part of the voltage change curve divided by adjacent dividing lines are obtained, and they are integrated into a curve group. Based on multiple dividing lines, there are multiple curve groups. Based on the change synchronization analysis of part of the first output power change curve and part of the voltage change curve in the curve group, a trend synchronization ratio and an amplitude synchronization ratio are obtained, and the trend synchronization ratio and the amplitude synchronization ratio are summed to obtain an impact correlation value.

[0026] As a further technical solution of the present invention, the generation method of the influence signal is:

[0027] comparing the impact association value to an impact association threshold;

[0028] If the impact correlation value is greater than the impact correlation threshold, it means that the output power change of the distributed energy will affect the voltage fluctuation of the distribution network, and an impact signal will be generated;

[0029] If the impact correlation value is less than or equal to the impact correlation threshold, it means that the output power change of distributed energy will not affect the fluctuation of distribution network voltage.

[0030] As a further technical solution of the present invention:

[0031] If the change trends of some first output power change curves and some voltage change curves in the curve group are the same, then the curve group is marked as a normal curve group;

[0032] If the change trends of some first output power change curves and some voltage change curves in the curve group are opposite, then the curve group is marked as an abnormal curve group;

[0033] The number of normal curve groups is counted, and the number of normal curve groups is ratioed with the number of curve groups to obtain the trend synchronization ratio.

[0034] As a further technical solution of the present invention, the end point values ​​of part of the first output power change curve in the normal curve group are obtained, and difference processing is performed on them to obtain the power change value, the end point values ​​of part of the voltage change curve in the normal curve group are obtained, and difference processing is performed on them to obtain the voltage change value, the voltage change value and the power change value are ratio processed to obtain the change ratio corresponding to the normal curve group, the change ratios corresponding to all the normal curve groups are summed and averaged to obtain the change ratio mean, the change ratio corresponding to the normal curve group and the change ratio mean are difference processed, and the absolute value of the difference is taken to obtain the change ratio deviation, all the change ratio deviations are summed and averaged to obtain the change ratio deviation mean, the change ratio deviation is compared with the change ratio deviation mean, if the change ratio deviation is greater than the change ratio deviation mean, the normal curve group corresponding to the change ratio deviation is marked as the abnormal synchronization curve group, if the change ratio deviation is less than or equal to the change ratio deviation mean, the normal curve group corresponding to the change ratio deviation is marked as the normal synchronization curve group;

[0035] The number of normal synchronization curve groups is counted, and the number of normal synchronization curve groups is ratio-processed with the number of normal curve groups to obtain the amplitude synchronization ratio.

[0036] As a further technical solution of the present invention, the output power of the distributed energy in the impact analysis period is obtained in real time, and marked and connected in the XY coordinate system to obtain a second output power change curve;

[0037] Measuring the overlap length between the first output power variation curve and the second output power variation curve, and performing ratio processing on the overlap length of the curve and the length of the second output power variation curve to obtain a first coincidence value;

[0038] The area enclosed by the first output power variation curve and the second output power variation curve is measured and marked as a discrete area, the area enclosed by the first output power variation curve and the X-axis is measured and marked as a reference area, and the discrete area is ratio-processed with the reference area to obtain a second coincidence value;

[0039] The first matching value is marked as DY;

[0040] The second coincidence value is marked as DR;

[0041] By formula: The change matching value BH is obtained, wherein s1 and s2 are both preset proportional coefficients.

[0042] As a further technical solution of the present invention, the distributed energy is sorted from large to small according to the change matching value to obtain the distributed energy troubleshooting path;

[0043] Based on the troubleshooting path of distributed energy, the distributed energy is checked in sequence;

[0044] The troubleshooting method is:

[0045] Keep the output power of other distributed energy sources unchanged, adjust the output power of the currently checked distributed energy source, and set the analysis period. At the end of the analysis period, measure the voltage change of the distribution network. The voltage change is the difference between the voltage value of the distribution network at the end of the analysis period and the voltage value of the distribution network at the beginning of the analysis period.

[0046] The voltage change is processed by ratioing the output power adjustment of the distributed energy currently being checked to obtain the impact degree value of the distributed energy currently being checked;

[0047] Distributed energy sources are reordered according to their impact levels, and the impact of distributed energy sources on voltage fluctuations in their distribution networks is evaluated.

[0048] The beneficial effects of the present invention are as follows:

[0049] 1. The present invention acquires voltage data of the distribution network in real time, constructs a voltage change curve of the distribution network in real time based on the voltage data of the distribution network, generates an operation signal based on position analysis of the voltage change curve, wherein the operation signal includes an operation signal and an analysis signal, performs mutation analysis on the voltage change curve of the power grid in real time based on the analysis signal, obtains a voltage change mutation value, judges the risk degree of voltage mutation of the distribution network according to the voltage change mutation value, and generates a risk signal, obtains power data of distributed energy connected to the distribution network based on the generation of a high-risk signal, wherein the power data includes output power, obtains an impact correlation value based on correlation analysis of the power data and the voltage data of the distribution network, judges whether the output power change of the distributed energy will affect the fluctuation of the distribution network voltage according to the impact correlation value, and generates an impact signal if it does, and realizes monitoring and identification of the voltage mutation risk of the distribution network and analyzing its influencing factors, which is conducive to subsequent rapid adjustment and optimization based on the influencing factors to ensure the safety of the distribution network operation.

[0050] 2. The present invention is based on generating an impact signal, analyzing and processing the power data of distributed energy to obtain a change matching value, determining a distributed energy investigation path based on the change matching value, and conducting an investigation and analysis on distributed energy based on the investigation path of distributed energy, and evaluating the degree of influence of distributed energy on the voltage fluctuation of its distribution network. The present invention effectively investigates distributed energy according to the influencing factors, and realizes the evaluation of the degree of influence of distributed energy on the voltage fluctuation of its distribution network. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The present invention will be further described below in conjunction with the accompanying drawings.

[0052] Figure 1 is a flow chart of Embodiment 1 of the present invention;

[0053] Figure 2 This is a flow chart of Embodiment 2 of the present invention. DETAILED DESCRIPTION

[0054] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods. Example 1

[0055] like Figure 1 As shown, a method for identifying risk of voltage fluctuation in a distribution network containing distributed energy sources according to an embodiment of the present invention includes:

[0056] Step 1: acquiring voltage data of the distribution network in real time, wherein the voltage data includes a voltage value, constructing a voltage change curve of the real-time operation of the distribution network based on the voltage data of the distribution network, and generating an operation signal based on a position analysis of the voltage change curve, wherein the operation signal includes an operation signal and an analysis signal;

[0057] In some embodiments, the voltage values ​​acquired in real time during the risk analysis period are marked in an XY coordinate system, and the voltage value marking points are connected to obtain a voltage change curve, wherein the X-axis represents time and the Y-axis represents voltage value;

[0058] It should be noted that the risk analysis cycle represents the duration of risk identification and analysis of the distribution network according to the distribution network analysis requirements;

[0059] Take the voltage standard threshold as the reference value, mark it on the Y axis, draw a straight line parallel to the X axis through the reference value mark point, and mark it as the voltage threshold line;

[0060] There are two voltage threshold lines, including a first voltage threshold line and a second voltage threshold line, and the first voltage threshold line is located above the second voltage threshold line;

[0061] It should be noted that the voltage standard threshold is the maximum and minimum value within the distribution network operating voltage standard range. The first voltage threshold line corresponds to the maximum value, and the second voltage threshold line corresponds to the minimum value.

[0062] The area between the first voltage threshold line and the second voltage threshold line is the normal operating area, and the area outside the normal operating area is the mutation analysis area, including the first mutation analysis area and the second mutation analysis area, wherein the first mutation analysis area represents the area above the first threshold line, and the second mutation analysis area represents the area between the second threshold line and the X-axis;

[0063] Obtain the voltage change curve and perform position analysis on it, specifically:

[0064] If the end point of the voltage variation curve is within the normal operating area, an operating signal is generated;

[0065] If the end point of the voltage change curve is within the mutation analysis region, an analysis signal is generated;

[0066] It should be noted that the operation signal indicates that the voltage change is within the normal range and the distribution network is operating normally, while the analysis signal indicates that the voltage change is not within the normal range and a voltage mutation analysis is required;

[0067] Step 2: Based on the analysis signal, a mutation analysis is performed on the voltage change curve of the real-time operation of the power grid to obtain a voltage change mutation value, and the voltage mutation risk degree of the distribution network is determined according to the voltage change mutation value, and a risk signal is generated, wherein the risk signal includes a high risk signal and a low risk signal;

[0068] In some embodiments, if the end point of the voltage change curve is within the first mutation analysis region, the trough point in the voltage change curve that is closest to the end point of the voltage change curve in horizontal distance is obtained, and is marked as the mutation starting point. The mutation starting point and the end point of the voltage change curve are connected by a straight line to obtain a mutation line. At the same time, a vertical line is drawn through the end point line of the voltage change curve to obtain a maximum mutation reference line. The angle between the mutation line and the maximum mutation reference line is measured and marked as the mutation angle. The mutation angle is ratioed with the right angle to obtain a mutation angle ratio.

[0069] The time points corresponding to the mutation starting point and the end point of the voltage change curve are obtained respectively, and difference processing is performed according to the time points to obtain the time difference between the mutation starting point and the end point of the voltage change curve, and the time difference is processed by ratio processing with the risk analysis period to obtain the mutation time ratio;

[0070] The obtained mutation angle ratio and mutation time ratio are processed to obtain the voltage change mutation value;

[0071] If the end point of the voltage change curve is within the second mutation analysis region, the peak point in the voltage change curve that is closest to the end point of the voltage change curve in horizontal distance is obtained, and it is marked as the mutation starting point. The mutation starting point and the end point of the voltage change curve are connected by a straight line to obtain a mutation line. At the same time, a vertical line is drawn through the X-axis of the end point line of the voltage change curve to obtain a maximum mutation reference line. The angle between the mutation line and the maximum mutation reference line is measured and marked as the mutation angle. The mutation angle is ratioed with the right angle to obtain a mutation angle ratio.

[0072] The time points corresponding to the mutation starting point and the end point of the voltage change curve are obtained respectively, and difference processing is performed according to the time points to obtain the time difference between the mutation starting point and the end point of the voltage change curve, and the time difference is processed by ratio processing with the risk analysis period to obtain the mutation time ratio;

[0073] The obtained mutation angle ratio and mutation time ratio are processed to obtain the voltage change mutation value;

[0074] In some embodiments, the voltage change mutation value is compared to a voltage change mutation threshold;

[0075] If the voltage change mutation value is greater than the voltage change mutation threshold, a high-risk signal is generated;

[0076] If the voltage change mutation value is less than or equal to the voltage change mutation threshold, a low risk signal is generated;

[0077] It should be noted that a high-risk signal indicates that the voltage has undergone a significant and sustained increase or decrease mutation in a short period of time, whereas a low-risk signal indicates that the voltage has not undergone a significant and sustained increase or decrease mutation in a short period of time;

[0078] Step 3: Based on the generation of high-risk signals, the power data of the distributed energy connected to the distribution network is obtained, wherein the power data includes the output power. Based on the correlation analysis of the power data and the voltage data of the distribution network, the impact correlation value is obtained. According to the impact correlation value, it is determined whether the output power change of the distributed energy will affect the fluctuation of the distribution network voltage. If so, an impact signal is generated;

[0079] In some embodiments, the output power of all distributed energy sources is acquired in real time, and the sum is averaged to obtain the real-time output power average of the distributed energy sources, and the real-time output power average of the distributed energy sources is marked and connected in an XY coordinate system to obtain a first output power change curve, wherein the X-axis represents time and the Y-axis represents output power;

[0080] Mark the period between the time point corresponding to the end point of the voltage change curve and the start time point of the risk analysis period as the impact analysis period, divide the impact analysis period into a number of time analysis nodes, mark the time analysis nodes on the X-axis in the coordinate system where the first output power change curve and the voltage change curve are located according to the corresponding time points, draw a straight line parallel to the Y-axis through the marked points of the time analysis nodes, and mark it as a dividing line, divide the first output power change curve and the voltage change curve through the dividing line, obtain the part of the first output power change curve and the part of the voltage change curve divided by the adjacent dividing lines, and integrate them into a curve group, and there are multiple curve groups based on multiple dividing lines;

[0081] A change synchronization analysis is performed on part of the first output power change curve and part of the voltage change curve in the curve group, specifically:

[0082] If the change trends of some first output power change curves and some voltage change curves in the curve group are the same, then the curve group is marked as a normal curve group;

[0083] If the change trends of some first output power change curves and some voltage change curves in the curve group are opposite, then the curve group is marked as an abnormal curve group;

[0084] Count the number of normal curve groups, and perform ratio processing on the number of normal curve groups and the number of curve groups to obtain the trend synchronization ratio;

[0085] Obtain the endpoint values ​​of some of the first output power change curves in the normal curve group, and perform difference processing on them to obtain the power change value, obtain the endpoint values ​​of some of the voltage change curves in the normal curve group, and perform difference processing on them to obtain the voltage change value, perform ratio processing on the voltage change value and the power change value to obtain the change ratio corresponding to the normal curve group, sum and average the change ratios corresponding to all the normal curve groups to obtain the change ratio mean, perform difference processing on the change ratio corresponding to the normal curve group and the change ratio mean, and take the absolute value of the difference to obtain the change ratio deviation, sum and average all the change ratio deviations to obtain the change ratio deviation mean, compare the change ratio deviation with the change ratio deviation mean, if the change ratio deviation is greater than the change ratio deviation mean, mark the normal curve group corresponding to its change ratio deviation as the abnormal synchronization curve group, if the change ratio deviation is less than or equal to the change ratio deviation mean, mark the normal curve group corresponding to its change ratio deviation as the normal synchronization curve group;

[0086] Counting the number of normal synchronization curve groups, performing ratio processing on the number of normal synchronization curve groups and the number of normal curve groups, and obtaining an amplitude synchronization ratio;

[0087] The trend synchronization ratio and the amplitude synchronization ratio are summed to obtain the impact correlation value;

[0088] In some embodiments, the impact correlation value is compared to an impact correlation threshold;

[0089] If the impact correlation value is greater than the impact correlation threshold, it means that the output power change of the distributed energy will affect the voltage fluctuation of the distribution network, and an impact signal will be generated;

[0090] If the impact correlation value is less than or equal to the impact correlation threshold, it means that the output power change of distributed energy will not affect the fluctuation of distribution network voltage;

[0091] If the output power change of distributed energy will not cause the voltage fluctuation of the distribution network, other influencing factors shall be analyzed, including but not limited to the capacity and location of distributed energy;

[0092] The technical solution of the embodiment of the present invention is: acquiring the voltage data of the distribution network in real time, constructing the voltage change curve of the real-time operation of the distribution network based on the voltage data of the distribution network, generating an operation signal based on the position analysis of the voltage change curve, wherein the operation signal includes an operation signal and an analysis signal, and based on the analysis signal, performing mutation analysis on the voltage change curve of the real-time operation of the power grid to obtain a voltage change mutation value, judging the degree of voltage mutation risk of the distribution network according to the voltage change mutation value, and generating a risk signal, and based on the generation of a high-risk signal, obtaining the power data of the distributed energy connected to the distribution network, wherein the power data includes output power, and obtaining an impact correlation value based on correlation analysis of the power data and the voltage data of the distribution network, and judging whether the output power change of the distributed energy will affect the fluctuation of the distribution network voltage according to the impact correlation value, and if so, generating an impact signal, the present invention realizes the monitoring and identification of the voltage mutation risk of the distribution network, and analyzes its influencing factors, which is conducive to subsequent rapid adjustment and optimization based on the influencing factors, and ensures the safety of the operation of the distribution network. Example 2

[0093] like Figure 2 As shown, a method for identifying risk of voltage fluctuation in a distribution network containing distributed energy sources according to an embodiment of the present invention further includes:

[0094] Step 4: Based on the generated impact signal and the power data of the distributed energy, the change matching value is obtained through analysis and processing, the distributed energy troubleshooting path is determined based on the change matching value, and the distributed energy is troubleshooted and analyzed based on the distributed energy troubleshooting path to evaluate the impact of the distributed energy on the voltage fluctuation of its distribution network;

[0095] Specifically, the output power of the distributed energy in the impact analysis period is obtained in real time, and marked and connected in the XY coordinate system to obtain a second output power change curve;

[0096] Measuring the overlap length between the first output power variation curve and the second output power variation curve, and performing ratio processing on the overlap length of the curve and the length of the second output power variation curve to obtain a first coincidence value;

[0097] The area enclosed by the first output power variation curve and the second output power variation curve is measured and marked as a discrete area, the area enclosed by the first output power variation curve and the X-axis is measured and marked as a reference area, and the discrete area is ratio-processed with the reference area to obtain a second coincidence value;

[0098] The first matching value is marked as DY;

[0099] The second coincidence value is marked as DR;

[0100] By formula: The change matching value BH is obtained, wherein s1 and s2 are both preset proportional coefficients;

[0101] It should be noted that a technician in this field collects multiple groups of sample data and sets a corresponding preset proportional coefficient for each group of sample data; substitutes the preset proportional coefficient and the collected sample data into the formula, any two formulas form a binary linear equation system, and the calculated coefficients are screened and averaged to obtain s1 and s2;

[0102] In some embodiments, the distributed energy sources are sorted from large to small according to the change matching values ​​to obtain a troubleshooting path for the distributed energy sources;

[0103] Based on the troubleshooting path of distributed energy, the distributed energy is checked in sequence;

[0104] The troubleshooting method is:

[0105] Keep the output power of other distributed energy sources unchanged, adjust the output power of the currently checked distributed energy source, and set the analysis period. At the end of the analysis period, measure the voltage change of the distribution network. The voltage change is the difference between the voltage value of the distribution network at the end of the analysis period and the voltage value of the distribution network at the beginning of the analysis period.

[0106] The voltage change is processed by ratioing the output power adjustment of the distributed energy currently being checked to obtain the impact degree value of the distributed energy currently being checked;

[0107] It should be noted that when troubleshooting distributed energy resources, the analysis period set is the same;

[0108] Re-rank the distributed energy resources according to their impact levels, and complete the evaluation of the impact of distributed energy resources on the voltage fluctuation of its distribution network;

[0109] The technical solution of the embodiment of the present invention is: based on generating an influence signal, based on the power data of distributed energy, analyzing and processing to obtain a change matching value, determining a distributed energy inspection path based on the change matching value, inspecting and analyzing distributed energy based on the inspection path of distributed energy, and evaluating the degree of influence of distributed energy on the voltage fluctuation of its distribution network. The present invention effectively inspects distributed energy according to the influencing factors, and realizes the evaluation of the degree of influence of distributed energy on the voltage fluctuation of its distribution network.

[0110] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for identifying the risk of voltage fluctuation in a distribution network containing distributed energy, characterized in that: include: Step 1: Obtain the voltage value of the distribution network in real time, construct a voltage change curve of the real-time operation of the distribution network based on the voltage value of the distribution network, and obtain an analysis signal based on position analysis of the voltage change curve; Step 2: Based on the analysis signal, a voltage change curve of the real-time operation of the power grid is subjected to mutation analysis to obtain a voltage change mutation value, and the voltage change mutation value is compared with a voltage change mutation threshold. If the voltage change mutation value is greater than the voltage change mutation threshold, a high-risk signal is generated; Step 3: Based on the high-risk signal, the power data of the distributed energy connected to the distribution network is obtained, wherein the power data includes the output power. Based on the correlation analysis of the power data and the voltage data of the distribution network, the impact correlation value is obtained. According to the impact correlation value, it is determined whether the output power change of the distributed energy will affect the fluctuation of the distribution network voltage. If so, an impact signal is generated; The process of obtaining the impact association value includes: Obtain the real-time output power average of the distributed energy, mark and connect it in the XY coordinate system, and obtain a first output power change curve; Mark the period between the time point corresponding to the end point of the voltage change curve and the start time point of the risk analysis period as the impact analysis period, divide the impact analysis period into a number of time analysis nodes, draw a straight line parallel to the Y-axis through the time analysis nodes, divide the first output power change curve and the voltage change curve, obtain part of the first output power change curve and part of the voltage change curve, integrate them into a curve group, perform change synchronization analysis on part of the first output power change curve and part of the voltage change curve in the curve group, obtain the trend synchronization ratio and the amplitude synchronization ratio, and sum them to obtain the impact correlation value; Step 4: Based on the impact signal and the power data of the distributed energy, the change matching value is obtained through analysis and processing, and the inspection path of the distributed energy is determined based on the change matching value. The distributed energy is inspected and analyzed based on the inspection path of the distributed energy, and the influence of the distributed energy on the voltage fluctuation of its distribution network is evaluated; Measuring the overlap length between the first output power variation curve and the second output power variation curve, and performing ratio processing to obtain a first coincidence value, which is marked as DY; Measuring the area enclosed by the first output power variation curve and the second output power variation curve, and the area enclosed by the first output power variation curve and the X-axis, and performing ratio processing to obtain a second coincidence value, marked as DR; By formula: The change matching value BH is obtained, wherein s1 and s2 are both preset proportional coefficients.

2. The method for identifying risk of voltage fluctuation in a distribution network containing distributed energy according to claim 1, characterized in that: The analysis signal is generated in the following manner: The voltage value obtained in real time is marked in the XY coordinate system, and the voltage value marking points are connected to obtain a voltage change curve, where the X axis represents time and the Y axis represents voltage value; Take the voltage standard threshold as the reference value, mark it on the Y axis, draw a straight line parallel to the X axis through the reference value mark point, and mark it as the voltage threshold line; There are two voltage threshold lines, including a first voltage threshold line and a second voltage threshold line, and the first voltage threshold line is located above the second voltage threshold line; The area between the first voltage threshold line and the second voltage threshold line is the normal operating area, and the area outside the normal operating area is the mutation analysis area, including the first mutation analysis area and the second mutation analysis area, wherein the first mutation analysis area represents the area above the first threshold line, and the second mutation analysis area represents the area between the second threshold line and the X-axis; If the end point of the voltage variation curve is within the normal operating area, an operating signal is generated; If the end point of the voltage change curve is within the mutation analysis region, an analysis signal is generated.

3. The method for identifying the risk of voltage fluctuation in a distribution network containing distributed energy according to claim 2, characterized in that: The voltage change mutation value is obtained in the following manner: If the end point of the voltage change curve is within the first mutation analysis region, the trough point in the voltage change curve that is closest to the end point of the voltage change curve in horizontal distance is obtained, and it is marked as the mutation starting point. If the end point of the voltage change curve is within the second mutation analysis region, the peak point in the voltage change curve that is closest to the end point of the voltage change curve in horizontal distance is obtained, and it is marked as the mutation starting point. The mutation starting point and the end point of the voltage change curve are connected by a straight line to obtain a mutation line. At the same time, a vertical line is drawn through the end point of the voltage change curve to the X-axis to obtain a maximum mutation reference line. The angle between the mutation line and the maximum mutation reference line is measured and marked as the mutation angle. The mutation angle is ratioed with the right angle to obtain a mutation angle ratio. The time points corresponding to the mutation starting point and the end point of the voltage change curve are obtained respectively, and difference processing is performed according to the time points to obtain the time difference between the mutation starting point and the end point of the voltage change curve, and the time difference is processed by ratio processing with the risk analysis period to obtain the mutation time ratio; The obtained mutation angle ratio and mutation time ratio are processed by ratio processing to obtain the voltage change mutation value.

4. The method for identifying risk of voltage fluctuation in a distribution network containing distributed energy according to claim 1, characterized in that: The generation method of the impact signal is: comparing the impact association value to an impact association threshold; If the impact correlation value is greater than the impact correlation threshold, it means that the output power change of the distributed energy will affect the voltage fluctuation of the distribution network, and an impact signal will be generated; If the impact correlation value is less than or equal to the impact correlation threshold, it means that the output power change of distributed energy will not affect the fluctuation of distribution network voltage.

5. The method for identifying risk of voltage fluctuation in a distribution network containing distributed energy according to claim 1, characterized in that: The trend synchronization ratio is obtained as follows: If the change trends of some first output power change curves and some voltage change curves in the curve group are the same, then the curve group is marked as a normal curve group; The number of normal curve groups is counted, and the number of normal curve groups is ratioed with the number of curve groups to obtain the trend synchronization ratio.

6. The method for identifying risk of voltage fluctuation in a distribution network containing distributed energy according to claim 1, characterized in that: The amplitude synchronization ratio is obtained as follows: Obtain the endpoint values ​​of some of the first output power change curves in the normal curve group, and perform difference processing on them to obtain the power change value, obtain the endpoint values ​​of some of the voltage change curves in the normal curve group, and perform difference processing on them to obtain the voltage change value, perform ratio processing on the voltage change value and the power change value to obtain the change ratio corresponding to the normal curve group, sum and average the change ratios corresponding to all the normal curve groups to obtain the change ratio mean, perform difference processing on the change ratio corresponding to the normal curve group and the change ratio mean, and take the absolute value of the difference to obtain the change ratio deviation, sum and average all the change ratio deviations to obtain the change ratio deviation mean, compare the change ratio deviation with the change ratio deviation mean, if the change ratio deviation is less than or equal to the change ratio deviation mean, mark the normal curve group corresponding to its change ratio deviation as the normal synchronization curve group; The number of normal synchronization curve groups is counted, and the number of normal synchronization curve groups is ratio-processed with the number of normal curve groups to obtain the amplitude synchronization ratio.

7. The method for identifying the risk of voltage fluctuation in a distribution network containing distributed energy according to claim 1, characterized in that: The process of investigating and analyzing distributed energy and evaluating the impact of distributed energy on the voltage fluctuation of its distribution network includes: Sort the distributed energy sources according to the change matching values ​​from large to small to obtain the troubleshooting path of the distributed energy sources; Based on the troubleshooting path of distributed energy, the distributed energy is checked in sequence; The troubleshooting method is: Keep the output power of other distributed energy sources unchanged, adjust the output power of the currently checked distributed energy source, and set the analysis period. At the end of the analysis period, measure the voltage change of the distribution network. The voltage change is the difference between the voltage value of the distribution network at the end of the analysis period and the voltage value of the distribution network at the beginning of the analysis period. The voltage change is processed by ratioing the output power adjustment of the distributed energy currently being checked to obtain the impact degree value of the distributed energy currently being checked; Distributed energy sources are reordered according to their impact levels, and the impact of distributed energy sources on voltage fluctuations in their distribution networks is evaluated.

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