Early insulation fault location method for distribution network cable lines

Abstract

The present invention discloses an early insulation fault location method for distribution network cable lines, which relates to the technical field of power system monitoring. It converts the information of line electrical variable data to obtain electrical variable signals, extracts features of the set local suppression index to obtain equilibrium variable coefficients; constructs a periodic variable dynamic graph based on the equilibrium variable coefficients and conducts adjacent difference accounting to obtain an adjacent wave coefficient difference graph; sets a fluctuation threshold range to verify the adjacent wave coefficient difference graph to obtain a verification result, matches the position of abnormal data according to the verification result to obtain abnormal position information; traces the source of qualified data according to the verification result to obtain qualified capture ends, and conducts mobile traversal monitoring on the qualified capture ends in the constructed virtual power grid topology space; accurately locates the insulation fault point, prevents major faults from occurring, and improves power supply continuity.

Description

Technical Field

[0001] The present invention relates to the technical field of power system monitoring, and specifically to a method for early insulation fault location of distribution network cable lines. Background Art

[0002] With the acceleration of the urbanization process, the cable rate of the distribution network has increased significantly, and cable lines have become the core carriers of power transmission. However, during long-term operation, cables are vulnerable to environmental erosion, mechanical stress, electrothermal aging and other factors, resulting in a gradual deterioration of the insulation performance, and further causing early insulation defects such as partial discharge and tree-like discharge. If not detected and located in time, such hidden dangers will gradually evolve into obvious faults such as short circuits and groundings, leading to large-scale power outages and even equipment damage.

[0003] Traditional cable fault location methods mainly target the obvious states after the occurrence of faults. Such methods have insufficient sensitivity to the weak signals of early insulation defects and need to be triggered after the occurrence of faults, and cannot achieve preventive maintenance. Precise location during the latent period when the cable insulation performance has become abnormal but has not yet caused obvious faults such as system short circuits, groundings or power outages can prevent major faults from occurring, reduce the power outage time of users, and improve power supply continuity. Therefore, a method for early insulation fault location of distribution network cable lines is provided. Summary of the Invention

[0004] The object of the present invention can be achieved by the following technical solutions:

[0005] A method for early insulation fault location of distribution network cable lines, comprising the following steps:

[0006] Step S1: Construct a virtual power grid topology space, collect line electrical variable data, and mark the measurement time;

[0007] Step S2: Perform information conversion on the line electrical variable data to obtain electrical variable signals, extract the set local suppression index according to the electrical variable signals to obtain local characteristic indexes, perform segmented statistics on the local characteristic indexes, and perform separation transformation with the electrical variable signals to obtain sub-control variable coefficients, perform discrete docking on the electrical variable signals to obtain stage variable coefficient segments, and perform balanced sampling on the sub-control variable coefficients according to the stage variable coefficient segments to obtain balanced variable coefficients;

[0008] Step S3: Generate a balanced coefficient wave according to the balanced variable coefficients, construct a periodic variable dynamic graph, perform sequence integration on the periodic variable dynamic graph to obtain a balanced wave time series, and perform adjacent difference accounting on the balanced wave time series to obtain an adjacent wave coefficient difference graph;

[0009] Step S4: Set a fluctuation threshold range to verify the adjacent wave coefficient difference graph, obtain a verification result, determine the balanced wave time series according to the verification result, obtain abnormal determination data and qualified determination data, perform position matching on the abnormal determination data, and obtain abnormal position information;

[0010] Step S5: Trace the source of the qualified determination data to obtain a qualified capture end, perform mobile monitoring on the qualified capture end to obtain an updated mobile end, and traverse and monitor the virtual power grid topology space through the updated mobile end.

[0011] Preferably, the process of constructing the virtual power grid topology space and collecting line electrical variable data includes:

[0012] Globally integrate the distribution network cable lines to obtain topological comprehensive data;

[0013] Construct an original virtual space, upload the topological comprehensive data to the original virtual space, and perform structure virtualization on the topological comprehensive data through the original virtual space to obtain the virtual power grid topology space;

[0014] Perform troubleshooting settings on the distribution network cable lines to obtain a mobile capture end, and map the mobile capture end to the virtual power grid topology space to obtain available monitoring points;

[0015] Measure and collect the distribution network cable lines through the mobile capture end to obtain line electrical variable data, and perform time marking on the measurement and collection to obtain the measurement time.

[0016] Preferably, the process of extracting the set local suppression index according to the electrical variable signal includes:

[0017] Perform vibration capture through the electrical variable signal to obtain frequency characteristics, and perform characteristic fusion on the frequency characteristics to obtain integrated frequencies;

[0018] Set a local suppression index based on the electrical variable signal, and perform combined extraction of the local suppression index according to the integrated frequencies to obtain a local characteristic index.

[0019] Preferably, the process of performing segmented statistics on the local characteristic index and performing separation transformation with the electrical variable signal includes:

[0020] Perform central transformation on the local characteristic index to obtain a control factor, and perform spacing statistics on the control factor according to the frequency characteristics to obtain a regulation base number;

[0021] Discretely segment the local characteristic index through the regulation base number to obtain a regulation characteristic index segment;

[0022] Upload the regulation characteristic index segment to the electrical variable signal, and perform local separation on the electrical variable signal through the regulation characteristic index segment to obtain a sub-control variable coefficient.

[0023] Preferably, the process of discretely docking the electrical variable signal includes:

[0024] Discretely segment the electrical variable signal according to the regulation base number to obtain a regulation variable signal segment;

[0025] Based on the electrical variable signal, sequentially correspond the regulation characteristic index segment with the regulation variable signal segment according to the order of discrete segmentation, and extract and dock the regulation variable signal segment through the regulation characteristic index segment at the corresponding position to obtain a stage variable coefficient segment.

[0026] Preferably, the process of obtaining the equilibrium wave time series includes:

[0027] Construct a waveform for the equilibrium variable coefficient to obtain a variable coefficient dynamic diagram, where the variable coefficient dynamic diagram includes an equilibrium coefficient wave;

[0028] Set a verification period according to the measurement time, and assimilate and integrate the variable coefficient dynamic diagram based on the verification period to obtain a periodic variable dynamic diagram;

[0029] Based on the periodic variable dynamic diagram, sort the equilibrium coefficient waves in chronological order of the measurement time to obtain an equilibrium wave time series.

[0030] Preferably, the process of performing adjacent difference calculation on the equilibrium wave time series includes:

[0031] Select nodes for the equilibrium coefficient wave based on the periodic variable dynamic diagram to obtain wave nodes;

[0032] In the equilibrium wave time series, perform node calculation on the equilibrium coefficient wave ranked one position after the sorted wave with the equilibrium coefficient wave in the previous position to obtain an adjacent difference point coefficient, until in the equilibrium wave time series, perform node calculation on the equilibrium coefficient wave ranked last with the equilibrium coefficient wave ranked second to last, and complete the node calculation of the equilibrium wave time series;

[0033] Construct a two-dimensional rectangular coordinate system based on the wave nodes, generate an adjacent difference coefficient curve according to the adjacent difference point coefficient, and upload the obtained adjacent difference coefficient curve to the two-dimensional rectangular coordinate system to obtain an adjacent wave coefficient difference diagram.

[0034] Preferably, the process of obtaining the verification result includes:

[0035] Set a fluctuation threshold range, and upload the fluctuation threshold range to the adjacent wave coefficient difference diagram to obtain a fluctuation threshold axis;

[0036] Perform fluctuation verification on the adjacent wave coefficient difference diagram according to the fluctuation threshold axis to obtain a verification result.

[0037] Preferably, the process of performing position matching on the abnormal determination data includes:

[0038] Determine the result of the balanced wave time series according to the verification result to obtain abnormal determination data and qualified determination data;

[0039] Obtain the mobile capture end corresponding to the abnormal determination data, denoted as the abnormal capture end, and perform information matching in the virtual power grid topology space according to the abnormal capture end to obtain the abnormal position information.

[0040] Preferably, the process of traversing and monitoring the virtual power grid topology space by the updated mobile end includes:

[0041] Perform node mapping on the virtual power grid topology space according to the qualified capture end to obtain qualified monitoring points;

[0042] Perform mobile monitoring on the mobile capture end through the virtual power grid topology space based on the qualified monitoring points to obtain the updated mobile end;

[0043] Collect line electrical variable data through the updated mobile end, mark the measurement time, and repeat the processes of step S2, step S3, and step S4 for the collected line electrical variable data. When the updated mobile end is determined to be an abnormal capture end, obtain the abnormal position information. When the updated mobile end is determined to be a qualified capture end, repeat the mobile monitoring process for fault monitoring.

[0044] Compared with the prior art, the beneficial effects of the present invention are:

[0045] 1. Collect the electrical variable data of the distribution network cable line, convert the electrical variable data in different forms into signals for processing, extract the characteristics of the electrical variable signals, construct a waveform diagram, and set a monitoring period to construct the electrical variable waveform diagrams at different times within a period, which can comprehensively capture the fault characteristics, so as to more accurately judge whether there is an early insulation fault in the cable line;

[0046] 2. By differentially marking the electrical variable coefficient waves in the electrical variable waveform diagram, determine whether they meet the safety threshold, obtain abnormal determination data and qualified determination data, and perform position matching on the abnormal determination data by constructing a virtual power grid topology space to obtain the abnormal position information. The constructed virtual power grid topology space can provide richer positioning information and improve the accuracy and precision of fault location;

[0047] 3. At the same time, move the position of the collection end of the qualified determination data in the constructed virtual power grid topology space, which can collect the electrical variable data at different positions, perform real-time mobile monitoring and analysis, flexibly obtain the monitoring position, improve the fault capture rate, effectively reduce the missed judgment of the distribution network cable line faults, avoid electric shock accidents, and reduce the fire risk. Description of the Drawings

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0049] Figure 1 This is the schematic diagram of the present invention. Detailed implementation manners

[0050] The following will clearly and completely describe the technical solutions of the present invention in combination with the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0051] As Figure 1 shown, the early insulation fault location method for the distribution network cable line includes the following steps:

[0052] Step S1: Construct a virtual power grid topology space, collect line electrical variable data, and mark the measurement time;

[0053] Step S2: Perform information conversion on the line electrical variable data to obtain electrical variable signals, extract the set local suppression index according to the electrical variable signals to obtain local characteristic indexes, perform segmented statistics on the local characteristic indexes, and perform separation transformation with the electrical variable signals to obtain sub-control variable coefficients. Perform discrete docking on the electrical variable signals to obtain stage variable coefficient segments, and perform balanced sampling on the sub-control variable coefficients according to the stage variable coefficient segments to obtain balanced variable coefficients;

[0054] Step S3: Generate a balanced coefficient wave according to the balanced variable coefficients, construct a periodic variable dynamic graph, perform sequence integration on the periodic variable dynamic graph to obtain a balanced wave time series, and perform adjacent difference calculation on the balanced wave time series to obtain an adjacent wave coefficient difference graph;

[0055] Step S4: Set a fluctuation threshold range to verify the adjacent wave coefficient difference graph to obtain a verification result. Determine the balanced wave time series according to the verification result to obtain abnormal determination data and qualified determination data, and perform position matching on the abnormal determination data to obtain abnormal position information;

[0056] Step S5: Trace the data of the qualified determination data to obtain a qualified capture end, perform mobile monitoring on the qualified capture end to obtain an updated mobile end, and traverse and monitor the virtual power grid topology space through the updated mobile end.

[0057] It should be further noted that in the specific implementation process, the process of constructing the virtual power grid topological space and collecting line electrical variable data includes:

[0058] Globally integrate the distribution network cable lines to obtain topological comprehensive data;

[0059] The global integration means extracting the topological structure in the distribution network cable lines according to the actual structure of the distribution network cable lines in reality, and at the same time performing global collection to obtain various devices and lines of the distribution network cable lines based on the topological structure, which is recorded as topological comprehensive data, representing the data information of the components of the distribution network cable lines, and being able to restore the structure of the distribution network cable circuit in reality according to the topological comprehensive data;

[0060] Construct an original virtual space, upload the obtained topological comprehensive data to the original virtual space, and perform structure virtualization on the topological comprehensive data through the original virtual space to obtain the virtual power grid topological space;

[0061] Furthermore, the original virtual space is a blank virtual space used to carry the virtual display space of the virtualized distribution network cable lines. The structure virtualization means performing three-dimensional stereoscopic restoration in the original virtual space according to the obtained topological comprehensive data to generate a three-dimensional stereoscopic model of the distribution network cable lines, and the internal structure, connection method, and devices are exactly the same as those of the distribution network cable lines in reality;

[0062] Perform troubleshooting settings on the distribution network cable lines to obtain mobile capture ends, map the obtained mobile capture ends to the virtual power grid topological space to obtain available monitoring points, and associate the obtained mobile capture ends with the corresponding available monitoring points;

[0063] The troubleshooting settings mean performing troubleshooting in the distribution network cable lines and setting mobile capture ends, and synchronizing the position points of the mobile capture ends to the virtual power grid topological space to obtain available monitoring points;

[0064] Furthermore, the set mobile capture ends can move in the distribution network cable lines, and the moving distance and moving frequency are determined by the fault determination result. If no fault data is detected by the mobile capture ends at the available monitoring points within a certain period of time, the position of the mobile capture ends is moved to change the monitoring position;

[0065] Measure and collect the distribution network cable lines through the mobile capture ends to obtain line electrical variable data, and associate the obtained line electrical variable data with the corresponding mobile capture ends;

[0066] Time-stamp the acquired measurement acquisitions to obtain a measurement time, where the measurement time represents the time when the electrical variable data of each line is acquired, and associate the obtained electrical variable data of the line with the corresponding measurement time;

[0067] The electrical variable data of the line includes current data, voltage data, power data, frequency data, insulation resistance data, and harmonic data. Among them, the insulation resistance data is obtained by measuring the cable line with an insulation resistance test instrument and represents the insulation resistance value at the available monitoring point.

[0068] The process of extracting the set local suppression index according to the electrical variable signal includes:

[0069] Perform information conversion on the obtained electrical variable data of the line to obtain an electrical variable signal;

[0070] The information conversion means converting the obtained electrical variable data of the line into a signal form, that is, an electrical variable signal. According to the current data, voltage data, power data, frequency data, insulation resistance data, and harmonic data included in the electrical variable data of the line, the electrical variable signal includes a current variable signal, a voltage variable signal, a power variable signal, a frequency variable signal, an insulation resistance variable signal, and a harmonic variable signal;

[0071] Obtain the electrical variable signal, perform vibration capture on the obtained electrical variable signal to obtain a frequency characteristic. The vibration capture represents extracting the frequency characteristic in the electrical variable signal, denoted as the frequency characteristic. The frequency characteristic includes the highest frequency, the lowest frequency, and the center frequency;

[0072] Set a local suppression index based on the electrical variable signal. The manifestation form of the local suppression index is a function form and is selected based on the wavelet function. The wavelet function includes but is not limited to the Haar wavelet and the Symlet wavelet;

[0073] Perform characteristic fusion on the obtained frequency characteristics to obtain an integrated frequency. Mark the obtained integrated frequency as JC, where , represents the highest frequency, represents the lowest frequency, represents the center frequency;

[0074] Merge and extract the local suppression index according to the obtained integrated frequency to obtain a local characteristic index. The merge and extraction means performing convolution on the obtained integrated frequency and the local suppression index. The obtained result is the local characteristic index. Through convolution, the characteristics of the local suppression index and the electrical variable signal are more matched, enabling more significant features in the signal to be extracted after transformation, which is convenient for detection and analysis.

[0075] The process of segmentally statistically analyzing the local characteristic index and performing a separation transformation on the electrical variable signal includes:

[0076] Perform a central transformation on the obtained local characteristic index to obtain a control factor. The central transformation represents the stretching and translation transformation of the local characteristic index in the time dimension and the frequency dimension, and statistically analyze the distance of the stretching and translation transformation to obtain the control factor;

[0077] Perform a spacing statistic on the control factor according to the obtained frequency characteristics to obtain a regulation base number;

[0078] Mark the obtained regulation base number as TK, where , represents the length of the local characteristic index, represents the number of control factors on the local characteristic index, represents the control factor. For the obtained calculation result, perform a floor operation to obtain an integer regulation base number;

[0079] Discretely segment the local characteristic index by the regulation base number to obtain a regulated characteristic index segment;

[0080] The discrete segmentation means segmenting the local characteristic index into equal-length segments according to the number of the regulation base number to obtain regulated characteristic index segments of the same length, and the number of the obtained regulated characteristic index segments is equal to the regulation base number;

[0081] Upload the obtained regulated characteristic index segment to the electrical variable signal, and perform local separation on the electrical variable signal through the regulated characteristic index segment to obtain a sub-control variable coefficient;

[0082] It should be further noted that in the specific implementation process, the process of the local separation includes:

[0083] Based on the order of the discrete segmentation, upload the obtained regulated characteristic index segment to the electrical variable signal, and merge and extract the first regulated characteristic index segment with the electrical variable signal to obtain a local characteristic coefficient. Among them, the merge and extraction mark convolves the regulated characteristic index segment with the electrical variable signal;

[0084] Merge and extract the next regulated characteristic index segment with the electrical variable signal to obtain a local characteristic coefficient, until all the obtained regulated characteristic index segments are merged and extracted with the electrical variable signal in the order of the discrete segmentation, and statistically sum the obtained local characteristic coefficients to obtain a sub-control variable coefficient.

[0085] Discretely segment the electrical variable signal according to the obtained regulation base number to obtain a regulated variable signal segment;

[0086] Further, the lengths of the obtained regulated variable signal segments are the same, equal to the length of the regulation characteristic index segments, and the number of regulated variable signal segments = the number of regulation characteristic index segments = the regulation base number;

[0087] Based on the order of discrete segmentation of the electrical variable signal, the obtained regulation characteristic index segments and regulated variable signal segments are sequentially corresponded, and at the corresponding positions, the regulated variable signal segments are docked and extracted through the regulation characteristic index segments to obtain the stage variable coefficient segments;

[0088] Further, the said docking and extraction means merging and extracting the obtained regulation characteristic index segments and the regulated variable signal segments at the corresponding positions to obtain the stage variable coefficient segments until all the regulation characteristic index segments at the corresponding positions are merged and extracted with the regulated variable signal segments at the corresponding positions. Among them, the merging and extraction mark convolves the regulation characteristic index segments and the regulated variable signal segments;

[0089] Obtain the sub-controlled variable coefficients, and perform equalization sampling on the sub-controlled variable coefficients according to the obtained stage variable coefficient segments to obtain the equalized variable coefficients;

[0090] It should be further noted that in the specific implementation process, the process of the equalization sampling includes:

[0091] The obtained stage variable coefficient segments are sequentially uploaded to the sub-controlled variable coefficients, and the sub-controlled variable coefficients are merged and extracted through the stage variable coefficient segments to obtain the partial coefficient segments. Among them, the merging and extraction means that the stage variable coefficient segments convolve the sub-controlled variable coefficients;

[0092] Based on the order of docking and extraction, the next stage variable coefficient segment is merged and extracted with the sub-controlled variable coefficients until all the stage variable coefficient segments are merged and extracted with the sub-controlled variable coefficients, and the obtained partial coefficient segments are statistically summed to obtain the equalized variable coefficients. The manifestation form of the equalized variable coefficients is in the form of a signal;

[0093] Further, according to the current variable signal, voltage variable signal, power variable signal, frequency variable signal, insulation resistance variable signal and harmonic variable signal included in the electrical variable signal, the equalized variable coefficients include current variable coefficients, voltage variable coefficients, power variable coefficients, frequency variable coefficients, insulation resistance variable coefficients and harmonic variable coefficients.

[0094] The process of obtaining the equalized wave time series includes:

[0095] Obtain the equalized variable coefficients, perform waveform construction on the obtained equalized variable coefficients to obtain the variable coefficient dynamic diagram, and the variable coefficient dynamic diagram includes the equalized coefficient wave;

[0096] The waveform structure represents generating a waveform diagram according to the equalization variable coefficient, that is, a dynamic diagram of variable coefficients. Among them, if the manifestation form of the equalization variable coefficient is a signal form, the waveform generated according to the equalization variable coefficient is denoted as an equalization coefficient wave, and the waveform diagram containing the equalization coefficient wave is denoted as a dynamic diagram of variable coefficients. Since the equalization variable coefficient is obtained by processing electrical variable signals, for each line electrical variable data corresponding to an electrical variable signal, there is a corresponding measurement time, then the measurement time corresponding to the line electrical variable data is associated with the equalization coefficient wave.

[0097] Specifically, according to the current variable coefficient, voltage variable coefficient, power variable coefficient, frequency variable coefficient, insulation resistance variable coefficient, and harmonic variable coefficient included in the equalization variable coefficient, the equalization coefficient waves in the corresponding generated waveform diagram include current coefficient wave, voltage coefficient wave, power coefficient wave, frequency coefficient wave, insulation resistance coefficient wave, and harmonic coefficient wave. Then, the current coefficient wave, voltage coefficient wave, power coefficient wave, frequency coefficient wave, insulation resistance coefficient wave, and harmonic coefficient wave respectively correspond to a dynamic diagram of variable coefficients, that is, a dynamic diagram of variable coefficients represents the equalization coefficient wave corresponding to an equalization variable coefficient.

[0098] Set a verification period according to the obtained measurement time, and perform assimilation integration on the obtained dynamic diagram of variable coefficients based on the verification period to obtain a periodic variable dynamic diagram.

[0099] The assimilation integration means obtaining the dynamic diagram of variable coefficients generated by the electrical variable signals corresponding to all line electrical variable data within a verification period, classifying them according to the same line electrical variable data as one category, and integrating the dynamic diagrams of variable coefficients corresponding to the electrical variable signals of the same type into one dynamic diagram of variable coefficients to obtain a periodic variable dynamic diagram, indicating that the periodic variable dynamic diagram contains the equalization coefficient waves of a verification period, and the equalization coefficient waves correspond to the waveforms generated by the electrical variable signals of the same type. Each equalization coefficient wave represents the characteristic change waveform of the electrical variable signal corresponding to the measurement time. Then, in the periodic variable dynamic diagram, different equalization coefficient waves represent the characteristic change waveforms of the electrical variable signals at different measurement times. For example, if the electrical variable signal is a current variable signal, the constructed periodic variable dynamic diagram contains the equalization coefficient waves of the current variable signals corresponding to different measurement times within a verification period.

[0100] Among them, "the same type" means that according to the various types of signals included in the electrical variable signal, each type of signal is classified as the same type. For example, the current variable signal is one type, and the voltage variable signal is one type.

[0101] Based on the chronological order of the measurement time, perform time sorting on the equalization coefficient waves according to the periodic variable dynamic diagram to obtain an equalization wave time series.

[0102] The time sorting means sorting the equalization coefficient waves in the order of the measurement times associated with the equalization coefficient waves to obtain an equalization wave time series.

[0103] Perform adjacent difference calculation on the obtained equalization wave time series to obtain an adjacent wave coefficient difference diagram;

[0104] It should be further noted that in the specific implementation process, the adjacent difference calculation means successively performing node calculation on the equalization coefficient wave at the next position after sorting and the equalization coefficient wave at the previous position in the equalization wave time series, and constructing an adjacent wave coefficient difference diagram. The specific process includes:

[0105] Select nodes for the equalization coefficient waves based on the periodic variable dynamic diagram to obtain wave nodes. The node selection means uniformly selecting nodes with the same interval on the horizontal axis in the periodic variable dynamic diagram, and marking the intersection points of the nodes and the equalization coefficient waves as wave nodes. Then, the intersection points of the wave nodes and the vertical axis are the values of the equalization variable coefficients of the equalization coefficient waves;

[0106] Perform node calculation on the first sorted equalization coefficient wave according to the second sorted equalization coefficient wave in the equalization wave time series to obtain adjacent point coefficients;

[0107] The node calculation means subtracting the value at the corresponding wave node of the first sorted equalization coefficient wave from each wave node of the second sorted equalization coefficient wave to obtain wave node differences, taking the absolute value of each obtained wave node difference, and then summing the absolute values of the wave node differences to obtain adjacent point coefficients;

[0108] Perform node calculation on the second sorted equalization coefficient wave according to the third sorted equalization coefficient wave in the equalization wave time series to obtain adjacent point coefficients. The node calculation means subtracting the value at the corresponding wave node of the second sorted equalization coefficient wave from each wave node of the third sorted equalization coefficient wave to obtain wave node differences, and calculating to obtain adjacent point coefficients;

[0109] Continue to perform node calculation on the third sorted equalization coefficient wave according to the fourth sorted equalization coefficient wave until node calculation is performed on the last sorted equalization coefficient wave and the equalization coefficient wave at the position before the last one in the equalization wave time series, and count the obtained adjacent point coefficients;

[0110] Construct a two-dimensional rectangular coordinate system based on the wave nodes, generate an adjacent difference coefficient curve according to the adjacent point coefficients, and upload the obtained adjacent difference coefficient curve to the two-dimensional rectangular coordinate system to obtain an adjacent wave coefficient difference diagram;

[0111] The horizontal axis of the constructed two-dimensional rectangular coordinate system represents the wave nodes, and the vertical axis represents the adjacent difference point coefficient. Then, in the adjacent wave coefficient difference diagram, the first wave node represents the adjacent difference point coefficient between the second equilibrium coefficient wave and the first equilibrium coefficient wave in the equilibrium wave time series, the second wave node represents the adjacent difference point coefficient between the third equilibrium coefficient wave and the second equilibrium coefficient wave in the equilibrium wave time series, the third wave node represents the adjacent difference point coefficient between the fourth equilibrium coefficient wave and the third equilibrium coefficient wave in the equilibrium wave time series...

[0112] Set the fluctuation threshold range, which includes the upper fluctuation limit and the lower fluctuation limit. Mark the obtained upper fluctuation limit as B1 and the obtained lower fluctuation limit as B0. Then, the fluctuation threshold range is denoted as [B0, B1].

[0113] Upload the obtained fluctuation threshold range to the adjacent wave coefficient difference diagram to obtain the fluctuation threshold axis, which includes the upper fluctuation limit axis and the lower fluctuation limit axis. Among them, the upper fluctuation limit axis and the lower fluctuation limit axis are two parallel lines, and both are parallel to the horizontal axis of the adjacent wave coefficient difference diagram. The upper fluctuation limit axis is above the lower fluctuation limit axis, the value of the upper fluctuation limit axis is equal to B1, and the value of the lower fluctuation limit axis is equal to B0.

[0114] Based on the adjacent wave coefficient difference diagram, perform fluctuation verification on the adjacent difference coefficient curve according to the obtained fluctuation threshold axis to obtain the verification result, which includes the safe fluctuation section and the abnormal fluctuation section.

[0115] The process of the fluctuation verification includes:

[0116] In the adjacent wave coefficient difference diagram, perform range comparison on the adjacent difference coefficient curve according to the fluctuation threshold axis. When the adjacent difference point coefficients on the adjacent difference coefficient curve are all greater than or equal to the lower fluctuation limit axis and less than or equal to the upper fluctuation limit axis, then mark the adjacent difference coefficient curve as the safe fluctuation section, indicating that the difference change between the equilibrium coefficient waves at two adjacent measurement times is within the safe range and there is no time point with a large fluctuation.

[0117] When there is a part of the adjacent difference point coefficients on the adjacent difference coefficient curve that is less than the lower fluctuation limit axis or greater than the upper fluctuation limit axis, then obtain that part of the adjacent difference coefficient curve that is less than the lower fluctuation limit axis or greater than the upper fluctuation limit axis, and mark it as the abnormal fluctuation section, indicating that there is a node where the difference change between the equilibrium coefficient waves at two adjacent measurement times exceeds the safe range, that is, there is a node where the fluctuation range is not within the reasonable threshold.

[0118] Perform result determination on the equilibrium wave time series according to the obtained verification result to obtain the abnormal determination data and the qualified determination data.

[0119] Further, the result determination indicates that if there is an abnormal fluctuation segment in the check result in the balanced wave time series, in the balanced wave time series, the electrical variable signal of the balanced coefficient wave corresponding to the abnormal fluctuation segment is obtained, and according to the line electrical variable data corresponding to the electrical variable signal, the corresponding line electrical variable data is recorded as abnormal determination data, indicating that there is a fluctuation change in the line electrical variable data after a certain number of measurement times within the verification period, that is, it is determined as abnormal data. For example, if the fluctuation of the current data is an abnormal fluctuation segment after a certain number of measurement times, it indicates that within the verification period, the current fluctuates greatly, resulting in an increase in cable heating and further causing mechanical damage to the cable, which is a manifestation of the early insulation fault of the cable line;

[0120] If the check results are all safe fluctuation segments in the balanced wave time series, in the balanced wave time series, the line electrical variable data corresponding to the electrical variable signal of the balanced coefficient wave is recorded as qualified determination data, indicating that the fluctuation of the line electrical variable data within the verification period is within the safe range and there is no abnormal situation;

[0121] Obtain the mobile capture end corresponding to the abnormal determination data, denoted as the abnormal capture end, and perform information matching according to the abnormal capture end in the virtual power grid topology space to obtain the abnormal position information;

[0122] The information matching means obtaining the corresponding available monitoring points in the virtual power grid topology space according to the abnormal capture end, denoted as abnormal monitoring points. Then, the position points of the abnormal monitoring points in the virtual power grid topology space are the position points determined as abnormal determination data, that is, the position information of the fault point, denoted as abnormal position information. It can quickly locate the source of the abnormal determination data. According to the mobile capture end of the source, the position information can be quickly determined in the virtual power grid topology space, and the position information is visually displayed, which is conducive to tracking the changes of the abnormal data and flashing the indicator lights for the abnormal monitoring points, enabling the safety management personnel to quickly obtain the warning of the abnormal points in the distribution network cable line, improving the fault location efficiency, and ensuring the safe operation of the distribution network.

[0123] The process of traversing and monitoring the virtual power grid topology space by updating the mobile terminal includes:

[0124] Perform data tracing on the obtained qualified determination data to obtain the qualified capture end;

[0125] The data tracing means obtaining the mobile capture end corresponding to the qualified determination data, and denoting the obtained mobile capture end as the qualified capture end, indicating that within the verification period, the line electrical variable data collected by the qualified capture end is within the safe range and there is no abnormal data exceeding the safety threshold;

[0126] It should be further noted that in the specific implementation process, according to the line electrical variable data including current data, voltage data, power data, frequency data, insulation resistance data, and harmonic data, the line electrical variable data includes various types of electrical variables. The prerequisite for determining a qualified capture end is that all types of line electrical variable data of the qualified capture end are qualified judgment data. If one type of line electrical variable data is determined as abnormal judgment data, then this mobile capture end cannot be recorded as a qualified capture end and needs to be recorded as an abnormal capture end, and the abnormal location information is obtained through the virtual power grid topology space;

[0127] Based on the obtained qualified capture ends, node mapping is performed on the virtual power grid topology space to obtain qualified monitoring points;

[0128] The single-order mapping means obtaining the corresponding available monitoring points according to the qualified capture ends in the virtual power grid topology space, which are recorded as qualified monitoring points;

[0129] Based on the qualified monitoring points, mobile monitoring of the mobile capture end is performed through the virtual power grid topology space to obtain an updated mobile terminal;

[0130] The mobile monitoring means that in the virtual power grid topology space, the position of the qualified monitoring point is reset, and an available monitoring point is reset around the qualified monitoring point, which is recorded as the updated monitoring point, and the updated monitoring point does not coincide with other available monitoring points. According to the updated monitoring point, position mapping is performed on the distribution network cable line to obtain the updated mobile terminal corresponding to the updated monitoring point, and the function of the updated mobile terminal is exactly the same as that of the mobile capture end, but it is a mobile capture end with a changed position;

[0131] The line electrical variable data is collected through the updated mobile terminal, and the measurement time is marked. The process of step S2, step S3, and step S4 is repeated for the line electrical variable data. When the updated mobile terminal is determined as an abnormal capture end, the abnormal location information is obtained. When the updated mobile terminal is determined as a qualified capture end, the process of mobile monitoring is repeated, and continuous mobile monitoring is performed through the virtual power grid topology space until abnormal data is detected for alarm;

[0132] In particular, mobile monitoring means that if there is no abnormal data within the verification period, it means that the monitoring position of the mobile capture end is a safe period. Then the monitoring point is changed, the surrounding positions are collected, and the positions are continuously changed for real-time collection, effectively ensuring the comprehensiveness and real-time nature of fault detection. Different from the existing fixed and phased fault monitoring, it can discover the insulation faults of the distribution network cable line at the earliest time and greatly ensure the operation safety of the distribution network.

[0133] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only the specific embodiments. Obviously, according to the content of this specification, many modifications and variations can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for early insulation fault location of distribution network cable lines, characterized in that, It includes the following steps: Step S1: Construct a virtual power grid topology space, collect line electrical variable data, and mark the measurement time; Step S2: Perform information conversion on the line electrical variable data to obtain electrical variable signals; The process of extracting the set local suppression index according to the electrical variable signal includes: Perform vibration capture through the electrical variable signal to obtain frequency characteristics, and perform characteristic fusion on the frequency characteristics to obtain integrated frequencies; Set a local suppression index based on the electrical variable signal, and the local suppression index is in the form of a wavelet function; Combine and extract the local suppression index according to the integrated frequencies to obtain a local characteristic index; Perform segmented statistics on the local characteristic index, and perform separation transformation with the electrical variable signal to obtain a sub-control variable coefficient. Perform discrete docking on the electrical variable signal to obtain a stage variable coefficient segment, and perform balanced sampling on the sub-control variable coefficient according to the stage variable coefficient segment to obtain a balanced variable coefficient; Step S3: Generate a balanced coefficient wave according to the balanced variable coefficient, construct a periodic variable dynamic graph, perform sequence integration on the periodic variable dynamic graph to obtain a balanced wave time series, and perform adjacent difference calculation on the balanced wave time series to obtain an adjacent wave coefficient difference graph; Step S4: Set a fluctuation threshold range to verify the adjacent wave coefficient difference graph to obtain a verification result. Determine the balanced wave time series according to the verification result to obtain abnormal determination data and qualified determination data, and perform position matching on the abnormal determination data to obtain abnormal position information; Step S5: Trace the data of the qualified determination data to obtain a qualified capture end, perform mobile monitoring on the qualified capture end to obtain an updated mobile end, and traverse and monitor the virtual power grid topology space through the updated mobile end.

2. The early insulation fault location method for the distribution network cable line according to claim 1, characterized in that, The process of constructing a virtual power grid topology space and collecting line electrical variable data includes: Perform global integration on the distribution network cable lines to obtain topological comprehensive data; Construct an original virtual space, upload the topological comprehensive data to the original virtual space, and perform structural virtualization on the topological comprehensive data through the original virtual space to obtain a virtual power grid topology space; Perform troubleshooting settings on the distribution network cable lines to obtain a mobile capture end, and map the mobile capture end to the virtual power grid topology space to obtain available monitoring points; Measure and collect the distribution network cable lines through the mobile capture end to obtain line electrical variable data, and mark the measurement time for the measurement and collection to obtain the measurement time.

3. The early insulation fault location method for the distribution network cable line according to claim 1, characterized in that, The process of performing segmented statistics on the local characteristic index and performing separation transformation with the electrical variable signal includes: Perform central transformation on the local characteristic index to obtain a control factor, and perform spacing statistics on the control factor according to the frequency characteristics to obtain a regulation base number; Perform discrete segmentation on the local characteristic index through the regulation base number to obtain a regulation characteristic index segment; Upload the regulation characteristic index segment to the electrical variable signal, and perform local separation on the electrical variable signal through the regulation characteristic index segment to obtain a sub-control variable coefficient.

4. The early insulation fault location method for the distribution network cable line according to claim 3, characterized in that The process of performing discrete docking on the electrical variable signal includes: Perform discrete segmentation on the electrical variable signal according to the regulation base number to obtain a regulation variable signal segment; Based on the discrete segmented order of the electrical variable signals, the regulation characteristic index segments are sequentially corresponded to the regulation variable signal segments, and at the corresponding positions, the regulation variable signal segments are docked and extracted by the regulation characteristic index segments to obtain the stage variable coefficient segments.

5. The early insulation fault location method for the distribution network cable line according to claim 1, characterized in that The process of obtaining the equilibrium wave time series includes: Construct the waveform of the equilibrium variable coefficient to obtain the variable coefficient dynamic diagram, and the variable coefficient dynamic diagram includes the equilibrium coefficient wave; Set the verification period according to the measurement time, and based on the verification period, assimilate and integrate the variable coefficient dynamic diagram to obtain the periodic variable dynamic diagram; Based on the periodic variable dynamic diagram, sort the equilibrium coefficient waves in chronological order of the measurement time to obtain the equilibrium wave time series.

6. The early insulation fault location method for the distribution network cable line according to claim 1, characterized in that The process of performing adjacent difference calculation on the equilibrium wave time series includes: Select nodes for the equilibrium coefficient wave based on the periodic variable dynamic diagram to obtain wave nodes; In the equilibrium wave time series, perform node calculation on the equilibrium coefficient wave in the last sorted position and the previous equilibrium coefficient wave to obtain the adjacent difference point coefficient, until the equilibrium coefficient wave in the last sorted position in the equilibrium wave time series and the equilibrium coefficient wave in the second last sorted position are subjected to node calculation to complete the node calculation of the equilibrium wave time series; Construct a two-dimensional rectangular coordinate system based on the wave nodes, generate an adjacent difference coefficient curve according to the adjacent difference point coefficient, and upload the obtained adjacent difference coefficient curve to the two-dimensional rectangular coordinate system to obtain the adjacent wave coefficient difference diagram.

7. The early insulation fault location method for the distribution network cable line according to claim 1, characterized in that The process of obtaining the verification result includes: Set the fluctuation threshold range, and upload the fluctuation threshold range to the adjacent wave coefficient difference diagram to obtain the fluctuation threshold axis; Perform fluctuation verification on the adjacent wave coefficient difference diagram according to the fluctuation threshold axis to obtain the verification result.

8. The early insulation fault location method for the distribution network cable line according to claim 2, wherein The process of performing position matching on the abnormal judgment data includes: Judge the result of the equilibrium wave time series according to the verification result to obtain the abnormal judgment data and the qualified judgment data; Obtain the mobile capture end corresponding to the abnormal judgment data, denoted as the abnormal capture end, and perform information matching in the virtual power grid topology space according to the abnormal capture end to obtain the abnormal position information.

9. The early insulation fault location method for the distribution network cable line according to claim 8, characterized in that The process of traversing and monitoring the virtual power grid topology space through the updated mobile end includes: Perform node mapping on the virtual power grid topology space according to the qualified capture end to obtain qualified monitoring points; Based on the qualified monitoring points, perform mobile monitoring on the mobile capture end through the virtual power grid topology space to obtain the updated mobile end; Collect line electrical variable data through the updated mobile end, mark the measurement time, and repeat the processes of step S2, step S3, and step S4 for the collected line electrical variable data. When the updated mobile end is determined to be an abnormal capture end, obtain the abnormal position information. When the updated mobile end is determined to be a qualified capture end, repeat the process of mobile monitoring for fault monitoring.

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