Cable joint partial discharge on-line monitoring system and method

Abstract

The embodiment of the invention discloses a cable joint partial discharge on-line monitoring system and method, and the method comprises the steps: receiving a pulse current signal of a monitored cable joint, carrying out the signal processing of the pulse current signal, generating a partial discharge graph, carrying out the splitting processing of the partial discharge graph according to a preset period, and obtaining a plurality of curve data, performing anomaly identification on each curve data, and when abnormal curve data and a corresponding abnormal phase interval are identified, determining amplitudes and discharge times at the same position as the abnormal phase interval and the abnormal phase interval in each non-abnormal curve data as to-be-fitted curve data; and performing curve fitting based on each piece of to-be-fitted curve data and the abnormal phase interval to obtain a to-be-evaluated curve, obtaining each preset defect and a corresponding map feature, and performing comparison processing based on each map feature and the to-be-evaluated curve to obtain a partial discharge monitoring result. According to the scheme, the partial discharge of the cable joint can be reasonably monitored, and the monitoring accuracy and precision are ensured.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of cable monitoring technology, and in particular to an online monitoring system and method for partial discharge of cable joints. Background Art

[0002] The cable joint is the connection point between the various sections of the cable line, which is used to ensure that the cable forms a continuous circuit. Its main function is to make the line unobstructed, keep the cable sealed, and ensure the insulation level at the cable joint to ensure the safe and reliable operation of the cable. With the increase in the use of cable joints, their insulation performance is easily affected by many aspects, and the safety margin is small, which may cause various defects during production, manufacturing and use. It is more prone to failure than the cable body and is the weak link of the cable. If the defects of the cable joint are not handled in time, it may have a great impact on the normal use and safety of the cable system. Therefore, a real-time online monitoring system is needed for efficient monitoring.

[0003] In the related technologies, most of them determine whether partial discharge occurs at the cable joints by monitoring the power operation parameters at the cable joints. There is a lack of reasonable monitoring methods for partial discharge at the cable joints, and the safety hazards of the cable joints cannot be discovered in time, which affects the operation of the power system. Summary of the invention

[0004] The embodiment of the present invention provides an online monitoring system and method for partial discharge at cable joints, which solves the problem that the related art lacks a reasonable monitoring method for partial discharge phenomena at cable joints, and the safety hazards of cable joints cannot be discovered in time, which affects the operation of the power system. The system can realize reasonable monitoring of partial discharge at cable joints by comparing the abnormal partial discharge curve obtained by curve fitting with the characteristics of each defect, thereby ensuring the accuracy and precision of partial discharge monitoring at cable joints.

[0005] In a first aspect, an embodiment of the present invention provides a method for online monitoring of partial discharge of a cable joint, comprising:

[0006] Receive a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, perform signal processing on the pulse current signal and generate a partial discharge spectrum, split the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle in the preset period;

[0007] Performing abnormal identification on each of the curve data respectively, and when abnormal curve data and corresponding abnormal phase intervals are identified, determining the amplitude and discharge times at the same position as the abnormal phase interval and at the abnormal phase interval in each of the non-abnormal curve data as the curve data to be fitted, and performing curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain a curve to be evaluated;

[0008] Each preset defect and the corresponding graph feature are obtained, and a comparison process is performed based on the graph feature corresponding to each preset defect and the curve to be evaluated to obtain the partial discharge monitoring result of the monitoring cable joint.

[0009] Optionally, the performing abnormality identification on each of the curve data separately includes:

[0010] The amplitude and the number of discharges corresponding to each phase angle in the curve data are compared with the corresponding preset comparison values ​​in sequence, and whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data are determined according to the comparison results.

[0011] Optionally, determining whether the curve data is abnormal curve data and an abnormal phase interval of the abnormal curve data according to the comparison processing result includes:

[0012] Determine whether there are continuous amplitudes greater than a preset number or discharge times greater than the corresponding preset comparison values ​​in the comparison processing results. If so, determine the curve data as abnormal curve data, and determine the range of phase angles corresponding to each of the continuous preset number of amplitudes or discharge times as an abnormal phase interval.

[0013] Optionally, performing curve fitting based on each of the to-be-fitted curve data and the abnormal phase interval to obtain the to-be-evaluated curve includes:

[0014] The amplitude average value and the discharge number average value at each same phase angle position in each of the curve data to be fitted are calculated, and the curve to be evaluated is generated according to the correspondence between each of the amplitude average value and each of the discharge number average value and the abnormal phase interval.

[0015] Optionally, the spectrum features include characteristic phase intervals, amplitude features, and discharge features, and the partial discharge monitoring result of the monitoring cable joint is obtained by comparing the spectrum features corresponding to each of the preset defects with the curve to be evaluated, including:

[0016] Matching the abnormal phase interval corresponding to the curve to be evaluated with the characteristic phase interval in each of the spectrum features, and determining each of the spectrum features that successfully matches as the spectrum feature to be compared;

[0017] The partial discharge monitoring result of the monitoring cable joint is obtained by comparing the amplitude characteristics and the discharge characteristics in the to-be-compared spectrum characteristics with the to-be-evaluated curve.

[0018] Optionally, the amplitude feature includes an amplitude feature range and an amplitude feature change trend, the discharge feature includes a discharge number feature range, and the partial discharge monitoring result of the monitoring cable joint is obtained by comparing the amplitude feature and the discharge feature in the to-be-compared graph feature with the to-be-evaluated curve, including:

[0019] Identify the amplitude range, amplitude change trend and discharge number range in the curve to be evaluated, and compare the amplitude range, amplitude change trend and discharge number range with the amplitude characteristic range, amplitude characteristic change trend and discharge number characteristic range respectively;

[0020] In the case that all the comparisons are successful, it is determined that partial discharge exists in the monitoring cable joint, and the preset defect corresponding to the atlas feature to be compared is determined as the defect of the monitoring cable joint.

[0021] Optionally, the splitting of the partial discharge spectrum according to a preset period to obtain a plurality of curve data includes:

[0022] The partial discharge spectrum is split once every preset period to obtain a plurality of sub-partial discharge spectra, and the amplitude and discharge times corresponding to each phase angle in each of the sub-partial discharge spectra are identified and determined as corresponding curve data.

[0023] In a second aspect, an embodiment of the present invention further provides an online monitoring system for partial discharge of a cable joint, comprising:

[0024] A partial discharge spectrum generating module is used to receive the pulse current signal of the monitoring cable joint uploaded by the monitoring terminal, perform signal processing on the pulse current signal and generate a partial discharge spectrum;

[0025] A spectrum splitting and processing module, used for splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle in the preset period;

[0026] An abnormality identification module, used for identifying abnormalities of each of the curve data;

[0027] A curve fitting module is used to, when abnormal curve data and corresponding abnormal phase intervals are identified, determine the amplitude and discharge number at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data as the curve data to be fitted, and perform curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain a curve to be evaluated;

[0028] The monitoring result determination module is used to obtain each preset defect and the corresponding spectrum feature, and to obtain the partial discharge monitoring result of the monitoring cable joint based on the comparison processing of the spectrum features corresponding to each preset defect and the curve to be evaluated.

[0029] In a third aspect, an embodiment of the present invention further provides an online monitoring device for partial discharge of a cable joint, the device comprising:

[0030] one or more processors;

[0031] a storage device for storing one or more programs,

[0032] When the one or more programs are executed by the one or more processors, the one or more processors implement an online monitoring method for partial discharge of a cable joint as described in an embodiment of the present invention.

[0033] In a fourth aspect, an embodiment of the present invention further provides a storage medium storing computer executable instructions, wherein the computer executable instructions, when executed by a computer processor, are used to execute a method for online monitoring of partial discharge of a cable joint as described in an embodiment of the present invention.

[0034] In an embodiment of the present invention, a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal is received, the pulse current signal is signal processed and a partial discharge spectrum is generated, the partial discharge spectrum is split according to a preset period to obtain a plurality of curve data, the curve data includes the amplitude and the number of discharges corresponding to each phase angle in the preset period, each curve data is respectively identified as abnormal, and when the abnormal curve data and the corresponding abnormal phase interval are identified, the amplitude and the number of discharges at the same position as the abnormal phase interval and the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted, and the curve to be evaluated is obtained by curve fitting based on each curve data to be fitted and the abnormal phase interval, and each preset defect and the corresponding spectrum feature are obtained, and the spectrum feature corresponding to each preset defect and the curve to be evaluated are compared and processed to obtain the partial discharge monitoring result of the monitoring cable joint. This scheme realizes the reasonable monitoring of the partial discharge of the cable joint by comparing the abnormal partial discharge curve obtained by curve fitting with each defect feature, solves the problem that there is a lack of a reasonable monitoring method for the partial discharge phenomenon at the cable joint in the related technology, and the safety hazards of the cable joint cannot be discovered in time, which affects the operation of the power system, and ensures the accuracy and precision of the partial discharge monitoring at the cable joint. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart of a method for online monitoring of partial discharge of a cable joint provided by an embodiment of the present invention;

[0036] Figure 2 A flow chart of another method for online monitoring of partial discharge of cable joints provided by an embodiment of the present invention;

[0037] Figure 3 A flow chart of another method for online monitoring of partial discharge of cable joints provided by an embodiment of the present invention;

[0038] Figure 4 A flow chart of another method for online monitoring of partial discharge of cable joints provided by an embodiment of the present invention;

[0039] Figure 5 A module structure block diagram of a cable joint partial discharge online monitoring system provided by an embodiment of the present invention;

[0040] Figure 6 A schematic structural diagram of an online monitoring device for partial discharge of a cable joint provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention, rather than to limit the embodiments of the present invention. It is also necessary to explain that, for ease of description, only parts related to the embodiments of the present invention are shown in the accompanying drawings, rather than all structures.

[0042] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and or or" in the specification and claims represents at least one of the connected objects, and the character "or" generally indicates that the objects associated before and after are in an "or" relationship.

[0043] The embodiment of the present application provides an online monitoring method for partial discharge of cable joints, which can be applied to the monitoring scenario of partial discharge phenomenon of cable joints. The embodiment of the present application provides an online monitoring method for partial discharge of cable joints, in which the execution subject of each step can be a computer device, which refers to any electronic device with data calculation, processing and storage capabilities, such as mobile phones, PCs (Personal Computers), tablet computers and other terminal devices, and can also be servers and other devices, which are not limited in the embodiment of the present application.

[0044] Figure 1 A flow chart of a method for online monitoring of partial discharge of a cable joint provided by an embodiment of the present invention is as follows: Figure 1 As shown, specifically including:

[0045] Step S101, receiving a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, performing signal processing on the pulse current signal and generating a partial discharge spectrum, splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle within the preset period.

[0046] Among them, the monitoring terminal is used to characterize the terminal equipment used to monitor the pulse current signal at the cable joint. Monitor the cable joint. The pulse current signal refers to the current pulse generated by the local discharge phenomenon occurring at the cable joint. The partial discharge spectrum is used to characterize the partial discharge spectrum, which is a graphical tool for analyzing partial discharge activities, and is composed of the power frequency voltage phase angle, amplitude and number of discharges, and the amplitude and number of discharges correspond to the phase angle of the power frequency voltage. The preset period can be a pre-set period for splitting the partial discharge spectrum. The curve data can be the relevant data of the curves in each sub-spectrum obtained after the partial discharge spectrum is split. In one embodiment, after the partial discharge spectrum is generated, each split mark point in the partial discharge spectrum is determined and marked according to the preset period, and the partial discharge spectrum is split at each split mark point position to obtain multiple sub-partial discharge spectra, and the amplitude and number of discharges corresponding to each phase angle in each sub-partial discharge spectrum are identified and determined as the corresponding curve data. Optionally, a splitting processing method may be to split the partial discharge spectrum once every preset period to obtain multiple sub-partial discharge spectra, identify the amplitude and discharge times corresponding to each phase angle in each sub-partial discharge spectrum and determine them as corresponding curve data. An exemplary example may be that the preset period is 360° phase angle, then the partial discharge spectrum is split once every 360° phase angle to obtain multiple sub-partial discharge spectra, namely sub-partial discharge spectrum 1, sub-partial discharge spectrum 2 and sub-partial discharge spectrum 3, identify the amplitude and discharge times corresponding to each phase angle in sub-partial discharge spectrum 1, sub-partial discharge spectrum 2 and sub-partial discharge spectrum 3 and determine them as corresponding curve data. By splitting the partial discharge spectrum at a period scale, the partial discharge diagram of each voltage period can be obtained, which is convenient for subsequent operations.

[0047] Step S102, performing abnormal identification on each of the curve data respectively, and when abnormal curve data and corresponding abnormal phase intervals are identified, the amplitude and discharge number at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted.

[0048] Among them, the abnormal phase interval can be the range of the power frequency voltage phase angle corresponding to the abnormal part of the abnormal curve data. The curve data to be fitted is used to characterize the curve data used for curve fitting. In one embodiment, an abnormality identification method can be that each curve data is input into a trained abnormality identification model to obtain an output result, and the output result is non-abnormal curve data or abnormal curve data and the corresponding abnormal phase interval. Optionally, an abnormality identification method can be that the amplitude and the number of discharges corresponding to each phase angle in the curve data are compared with the corresponding preset comparison values ​​in turn, and whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data are determined according to the comparison processing results. By performing abnormal identification on each curve data separately, it can be determined whether there is abnormal data in each split part of the partial discharge spectrum of the cable joint, so as to determine whether to perform subsequent defect feature comparison.

[0049] An exemplary example may be that the individual curve data are curve data 1, curve data 2, and curve data 3, and curve data 1 is identified as abnormal curve data, and the abnormal phase interval is [90°, 180°]. Then, the amplitudes and discharge times corresponding to the phase angles [90°, 180°] in curve data 1, curve data 2, and curve data 3 are respectively determined as the curve data to be fitted, and curve data 1 to be fitted, curve data 2 to be fitted, and curve data 3 to be fitted are obtained.

[0050] Step S103: performing curve fitting based on each of the to-be-fitted curve data and the abnormal phase interval to obtain a to-be-evaluated curve.

[0051] Among them, the curve to be evaluated may be a curve waiting for defect evaluation. In one embodiment, after determining a plurality of curve data to be fitted, each curve data to be fitted is input into a preset curve fitting algorithm to obtain a curve to be evaluated, and the preset curve fitting algorithm may be an optimization algorithm such as the least squares method. Optionally, a curve fitting method may be to calculate the amplitude average value and the discharge number average value of each same phase angle position in each of the curve data to be fitted, and generate a curve to be evaluated according to each of the amplitude average values ​​and each of the discharge number average values ​​corresponding to the abnormal phase interval. Obtaining the curve to be evaluated by curve fitting can improve the accuracy and precision of partial discharge monitoring at cable joints.

[0052] Step S104, obtaining each preset defect and the corresponding graph feature, and performing comparison processing based on the graph feature corresponding to each preset defect and the curve to be evaluated to obtain the partial discharge monitoring result of the monitoring cable joint.

[0053] Among them, the spectrum features are used to characterize the characteristic data of the partial discharge spectrum of the preset defects. In one embodiment, after obtaining each preset defect and the corresponding spectrum features, the curve to be evaluated is input into the trained feature recognition model to obtain the corresponding curve features, and the curve features are respectively compared with the spectrum features of each preset defect to obtain the partial discharge monitoring results of the monitoring cable joint. Optionally, the spectrum features include characteristic phase intervals, amplitude features and discharge features. A method for determining the partial discharge monitoring results can be to match the abnormal phase intervals corresponding to the curve to be evaluated with the characteristic phase intervals in each spectrum feature, and determine each of the spectrum features that successfully matches as the spectrum features to be compared, and compare the amplitude features and discharge features in the spectrum features to be compared with the curve to be evaluated to obtain the partial discharge monitoring results of the monitoring cable joint. By screening out the spectrum features to be compared through the abnormal phase interval, the comparison workload can be reduced and the partial discharge monitoring efficiency of the cable joint can be improved.

[0054] As can be seen from the above, the pulse current signal of the monitoring cable joint uploaded by the monitoring terminal is received, the pulse current signal is signal processed and a partial discharge spectrum is generated, and the partial discharge spectrum is split according to the preset period to obtain multiple curve data, the curve data includes the amplitude and discharge times corresponding to each phase angle in the preset period, and each curve data is identified as abnormal. When the abnormal curve data and the corresponding abnormal phase interval are identified, the amplitude and discharge times at the same position as the abnormal phase interval and the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted, and the curve to be evaluated is obtained by curve fitting based on each curve data to be fitted and the abnormal phase interval, and each preset defect and the corresponding spectrum feature are obtained. The spectrum features corresponding to each preset defect and the curve to be evaluated are compared and processed to obtain the partial discharge monitoring result of the monitoring cable joint. This scheme realizes the reasonable monitoring of the partial discharge of the cable joint by comparing the abnormal partial discharge curve obtained by curve fitting with each defect feature, solves the problem that there is a lack of reasonable monitoring method for the partial discharge phenomenon at the cable joint in the related technology, and the safety hazards of the cable joint cannot be discovered in time, which affects the operation of the power system, and ensures the accuracy and precision of the partial discharge monitoring at the cable joint.

[0055] Figure 2 A flowchart of another method for online monitoring of partial discharge of cable joints provided by an embodiment of the present invention provides a specific method for optional abnormality identification, such as Figure 2 As shown, specifically including:

[0056] Step S201, receiving a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, performing signal processing on the pulse current signal and generating a partial discharge spectrum, splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle within the preset period.

[0057] Step S202: Compare the amplitude and discharge times corresponding to each phase angle in the curve data with the corresponding preset comparison values ​​in sequence, and determine whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data according to the comparison results.

[0058] The preset comparison value may be a preset standard comparison value of the amplitude or the number of discharges, which may be adjusted according to actual conditions. Optionally, a method for determining abnormal curve data may be to determine whether there are continuous amplitudes greater than a preset number or discharges greater than the corresponding preset comparison value in the comparison processing result. If so, the curve data is determined as abnormal curve data, and the range of phase angles corresponding to each continuous preset number of amplitudes or discharges is determined as an abnormal phase interval. An illustrative example may be that a plurality of curve data are curve data 1, curve data 2 and curve data 3, the preset comparison value corresponding to the amplitude is 10pC, the preset comparison value corresponding to the number of discharges is 5 times, the preset number is 10, and it is determined that there are 30 consecutive amplitudes greater than 10pC in curve data 2, and the phase angles corresponding to the 30 consecutive amplitudes are in the range of [90°, 120°]. In the comparison processing results of curve data 1 and curve data 3, there are no consecutive amplitudes greater than the preset number or the number of discharges is greater than the corresponding preset comparison value, then curve data 2 is determined as abnormal curve data, and the abnormal phase interval is [90°, 120°]. In another embodiment, the number of abnormal amplitudes and the number of abnormal discharge times are determined according to the comparison processing results, the abnormal amplitude is an amplitude greater than the corresponding preset comparison value, and the abnormal discharge number is the number of discharges greater than the corresponding preset comparison value. When the number of abnormal amplitudes or the number of abnormal discharges is greater than the preset number, the corresponding curve data is determined as abnormal curve data, and the minimum phase angle and the maximum phase angle of the phase angles corresponding to each abnormal amplitude or abnormal discharge number are determined, and the range from the minimum phase angle to the maximum phase angle is determined as the abnormal phase interval.

[0059] Step S203: when abnormal curve data and corresponding abnormal phase intervals are identified, the amplitude and discharge times at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted.

[0060] Step S204: performing curve fitting based on the data of each of the curves to be fitted and the abnormal phase interval to obtain a curve to be evaluated.

[0061] Step S205, obtaining each preset defect and the corresponding graph feature, and performing comparison processing based on the graph feature corresponding to each preset defect and the curve to be evaluated to obtain the partial discharge monitoring result of the monitoring cable joint.

[0062] As can be seen from the above, the amplitude and discharge times corresponding to each phase angle in the curve data are compared with the corresponding preset comparison values ​​in sequence, and whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data are determined according to the comparison processing results. This solution can determine whether there is abnormal data in each split part of the partial discharge spectrum of the cable joint by performing abnormal identification on each curve data separately, so as to determine whether to perform subsequent defect feature comparison.

[0063] Figure 3 A flowchart of another method for online monitoring of partial discharge of cable joints provided by an embodiment of the present invention provides a specific method for optional curve fitting, such as Figure 3 As shown, specifically including:

[0064] Step S301, receiving a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, performing signal processing on the pulse current signal and generating a partial discharge spectrum, splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle within the preset period.

[0065] Step S302, performing abnormal identification on each of the curve data respectively, and when abnormal curve data and corresponding abnormal phase intervals are identified, the amplitude and discharge times at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted.

[0066] Step S303, calculating the amplitude average value and the discharge number average value at each same phase angle position in each of the curve data to be fitted, and generating a curve to be evaluated according to the correspondence between each of the amplitude average value and each of the discharge number average values ​​and the abnormal phase interval.

[0067] The amplitude average value is used to represent the average value of each amplitude corresponding to the same phase angle position in each curve data to be fitted. The discharge number average value is used to represent the average value of each discharge number corresponding to the same phase angle position in each curve data to be fitted. An exemplary example may be that the curve data to be fitted are curve data 1 to be fitted, curve data 2 to be fitted, and curve data 3 to be fitted, respectively, the abnormal phase interval is [90°, 180°], the amplitude corresponding to the 90° phase angle in curve data 1 to be fitted is 15pC, the amplitude corresponding to the 90° phase angle in curve data 2 to be fitted is 9pC, and the amplitude corresponding to the 90° phase angle in curve data 3 to be fitted is 12pC, then the average amplitude corresponding to the 90° phase angle is 12pC, the number of discharges corresponding to the 90° phase angle in curve data 1 to be fitted is 6 times, the number of discharges corresponding to the 90° phase angle in curve data 2 to be fitted is 9 times, and the number of discharges corresponding to the 90° phase angle in curve data 3 to be fitted is 3 times, then the average number of discharges corresponding to the 90° phase angle is 6 times, and the average amplitude value and the average number of discharges corresponding to each phase angle in the abnormal phase interval [90°, 180°] are determined in the same way, and a curve to be evaluated is generated corresponding to the abnormal phase interval.

[0068] Step S304, obtaining each preset defect and the corresponding graph feature, and performing comparison processing based on the graph feature corresponding to each preset defect and the curve to be evaluated to obtain the partial discharge monitoring result of the monitoring cable joint.

[0069] From the above, it can be seen that the amplitude average value and the discharge number average value at each same phase angle position in each of the curve data to be fitted are calculated, and the curve to be evaluated is generated according to each of the amplitude average values ​​and each of the discharge number average values ​​corresponding to the abnormal phase interval. This solution obtains the curve to be evaluated by curve fitting, which can improve the accuracy and precision of partial discharge monitoring at the cable joint.

[0070] Figure 4 A flowchart of another method for online monitoring of partial discharge of cable joints provided by an embodiment of the present invention provides an optional specific method for determining partial discharge monitoring results, such as Figure 4 As shown, specifically including:

[0071] Step S401, receiving a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, performing signal processing on the pulse current signal and generating a partial discharge spectrum, splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle within the preset period.

[0072] Step S402: performing abnormal identification on each of the curve data respectively. When abnormal curve data and corresponding abnormal phase intervals are identified, the amplitude and discharge times at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted.

[0073] Step S403: performing curve fitting based on each of the to-be-fitted curve data and the abnormal phase interval to obtain a to-be-evaluated curve.

[0074] Step S404, obtaining each preset defect and the corresponding spectrum feature, matching the abnormal phase interval corresponding to the curve to be evaluated with the characteristic phase interval in each of the spectrum features, and determining each of the spectrum features that are successfully matched as the spectrum feature to be compared.

[0075] Among them, the spectrum features include characteristic phase intervals, amplitude features and discharge features. The characteristic phase interval can be the phase interval where the characteristic data in the partial discharge spectrum of the preset defect is located. The amplitude feature can be the characteristic data of the amplitude within the characteristic phase interval. The discharge feature is the characteristic data of the number of discharges within the characteristic phase interval. An exemplary example can be that the characteristic phase interval of the preset defect a is 90° to 180°, the characteristic phase interval of the preset defect b is 180° to 270°, the characteristic phase interval of the preset defect b is 270° to 360°, the characteristic phase interval of the preset defect d is 90° to 180°, and the abnormal phase interval corresponding to the curve to be evaluated is 90° to 180°, then the spectrum features of the preset defect a and the preset defect d are determined as the spectrum features to be compared.

[0076] Step S405: Compare the amplitude characteristics and discharge characteristics in the to-be-compared spectrum characteristics with the to-be-evaluated curve to obtain the partial discharge monitoring result of the monitoring cable joint.

[0077] Among them, optionally, the amplitude feature includes an amplitude feature range and an amplitude feature changing trend, the discharge feature includes a discharge number feature range, the amplitude feature range can be a size range of the amplitude in the characteristic phase interval when the corresponding preset defect occurs, the amplitude feature changing trend can be a changing trend of the amplitude in the characteristic phase interval when the corresponding preset defect occurs, and the discharge number feature range can be a size range of the discharge number in the characteristic phase interval when the corresponding preset defect occurs. A method for determining the local discharge monitoring result can be to identify the amplitude range, amplitude changing trend and discharge number range in the curve to be evaluated, and compare the amplitude range, amplitude changing trend and discharge number range with the amplitude feature range, amplitude feature changing trend and discharge number feature range respectively. When all comparisons are successful, it is determined that local discharge exists in the monitoring cable joint, and the preset defect corresponding to the spectrum feature to be compared is determined as the defect of the monitoring cable joint. An exemplary example may be that the amplitude characteristic range of the preset defect a is 25pC to 50pC, the amplitude characteristic change trend is an upward trend, the discharge number characteristic range is 6 to 10 times, the amplitude range in the curve to be evaluated is identified as 30pC to 40pC, the amplitude change trend is an upward trend, the discharge number range is 6 to 10 times, the amplitude range is within the amplitude characteristic range of the preset defect a, and the amplitude change trend is the same as the amplitude characteristic change trend, and the discharge number range is the same as the discharge number characteristic range, that is, all are successfully compared, and it is determined that the monitoring cable joint has a partial discharge phenomenon, and the defect is the preset defect a. In another embodiment, the curve amplitude feature and the curve discharge feature of the curve to be evaluated are identified based on the trained feature recognition model, and the first similarity between the curve amplitude feature and the amplitude feature in the to-be-compared spectrum feature and the second similarity between the curve discharge feature and the discharge feature in the to-be-compared spectrum feature are calculated. When the first similarity and the second similarity are both greater than the preset similarity, it is determined that the monitoring cable joint has a partial discharge phenomenon, and the preset defect corresponding to the to-be-compared spectrum feature is determined as the defect of the monitoring cable joint.

[0078] From the above, it can be seen that the abnormal phase interval corresponding to the curve to be evaluated is matched with the characteristic phase interval in each spectrum feature, and each spectrum feature that is successfully matched is determined as the spectrum feature to be compared, and the amplitude feature and discharge feature in the spectrum feature to be compared are compared with the curve to be evaluated to obtain the partial discharge monitoring result of the monitored cable joint. This scheme can reduce the comparison workload and improve the partial discharge monitoring efficiency of the cable joint by screening out the spectrum features to be compared through the abnormal phase interval.

[0079] Figure 5This is a module structure block diagram of a cable joint partial discharge online monitoring system provided by an embodiment of the present invention. The system is used to execute a cable joint partial discharge online monitoring method provided by the above embodiment, and has the corresponding functional modules and beneficial effects of the execution method. Figure 5 As shown, the system specifically includes:

[0080] The partial discharge spectrum generating module 101 is used to receive the pulse current signal of the monitoring cable joint uploaded by the monitoring terminal, perform signal processing on the pulse current signal and generate a partial discharge spectrum;

[0081] A spectrum splitting processing module 102, for splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle within the preset period;

[0082] An abnormality identification module 103, used for performing abnormality identification on each of the curve data;

[0083] The curve fitting module 104 is used to, when abnormal curve data and corresponding abnormal phase intervals are identified, determine the amplitude and discharge number at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data as the curve data to be fitted, and perform curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain a curve to be evaluated;

[0084] The monitoring result determination module 105 is used to obtain each preset defect and the corresponding spectrum feature, and to obtain the partial discharge monitoring result of the monitoring cable joint by comparing the spectrum features corresponding to each preset defect and the curve to be evaluated.

[0085] It can be seen from the above scheme that the pulse current signal of the monitoring cable joint uploaded by the monitoring terminal is received, the pulse current signal is signal processed and a partial discharge spectrum is generated, and the partial discharge spectrum is split according to the preset period to obtain multiple curve data, the curve data includes the amplitude and discharge times corresponding to each phase angle in the preset period, and each curve data is identified as abnormal. When the abnormal curve data and the corresponding abnormal phase interval are identified, the amplitude and discharge times at the same position as the abnormal phase interval and the abnormal phase interval in each non-abnormal curve data are respectively determined as the curve data to be fitted, and the curve to be evaluated is obtained by curve fitting based on each curve data to be fitted and the abnormal phase interval, and each preset defect and the corresponding spectrum feature are obtained. The spectrum features corresponding to each preset defect and the curve to be evaluated are compared and processed to obtain the partial discharge monitoring result of the monitoring cable joint. This scheme realizes the reasonable monitoring of the partial discharge of the cable joint by comparing the abnormal partial discharge curve obtained by curve fitting with each defect feature, solves the problem that there is a lack of reasonable monitoring method for the partial discharge phenomenon at the cable joint in the related technology, and the safety hazards of the cable joint cannot be discovered in time, which affects the operation of the power system, and ensures the accuracy and precision of the partial discharge monitoring at the cable joint.

[0086] In a possible embodiment, the abnormality identification module 103 is specifically used to:

[0087] The amplitude and the number of discharges corresponding to each phase angle in the curve data are compared with the corresponding preset comparison values ​​in sequence, and whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data are determined according to the comparison results.

[0088] In a possible embodiment, the abnormality identification module 103 is further used to:

[0089] Determine whether there are continuous amplitudes greater than a preset number or discharge times greater than the corresponding preset comparison values ​​in the comparison processing results. If so, determine the curve data as abnormal curve data, and determine the range of phase angles corresponding to each of the continuous preset number of amplitudes or discharge times as an abnormal phase interval.

[0090] In a possible embodiment, the curve fitting module 104 is specifically used for:

[0091] The amplitude average value and the discharge number average value at each same phase angle position in each of the curve data to be fitted are calculated, and the curve to be evaluated is generated according to the correspondence between each of the amplitude average value and each of the discharge number average value and the abnormal phase interval.

[0092] In a possible embodiment, the monitoring result determination module 105 is specifically used to:

[0093] Matching the abnormal phase interval corresponding to the curve to be evaluated with the characteristic phase interval in each of the spectrum features, and determining each of the spectrum features that successfully matches as the spectrum feature to be compared;

[0094] The partial discharge monitoring result of the monitoring cable joint is obtained by comparing the amplitude characteristics and the discharge characteristics in the to-be-compared spectrum characteristics with the to-be-evaluated curve.

[0095] In a possible embodiment, the monitoring result determination module 105 is further used to:

[0096] Identify the amplitude range, amplitude change trend and discharge number range in the curve to be evaluated, and compare the amplitude range, amplitude change trend and discharge number range with the amplitude characteristic range, amplitude characteristic change trend and discharge number characteristic range respectively;

[0097] In the case that all the comparisons are successful, it is determined that partial discharge exists in the monitoring cable joint, and the preset defect corresponding to the atlas feature to be compared is determined as the defect of the monitoring cable joint.

[0098] In a possible embodiment, the graph splitting processing module 102 is specifically used to:

[0099] The partial discharge spectrum is split once every preset period to obtain a plurality of sub-partial discharge spectra, and the amplitude and discharge times corresponding to each phase angle in each of the sub-partial discharge spectra are identified and determined as corresponding curve data.

[0100] Figure 6 A schematic diagram of the structure of an online monitoring device for partial discharge of a cable joint provided by an embodiment of the present invention is shown in FIG. Figure 6 As shown, the device includes a processor 201, a memory 202, an input device 203 and an output device 204; the number of processors 201 in the device can be one or more. Figure 6 A processor 201 is taken as an example; the processor 201, memory 202, input device 203 and output device 204 in the device can be connected by a bus or other means. Figure 6The example of connection via bus is taken. The memory 202, as a computer-readable storage medium, can be used to store software programs, computer executable programs and modules, such as program instructions or modules corresponding to a method for online monitoring of partial discharge of cable joints in an embodiment of the present invention. The processor 201 executes various functional applications and data processing of the device by running the software programs, instructions and modules stored in the memory 202, that is, realizes the above-mentioned method for online monitoring of partial discharge of cable joints. The input device 203 can be used to receive input digital or character information, and generate key signal input related to user settings and function control of the device. The output device 204 may include a display device such as a display screen.

[0101] An embodiment of the present invention further provides a storage medium comprising computer executable instructions, wherein the computer executable instructions are used to execute a method for online monitoring of partial discharge of a cable joint when executed by a computer processor, the method comprising:

[0102] Receive a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, perform signal processing on the pulse current signal and generate a partial discharge spectrum, split the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle in the preset period;

[0103] Performing abnormal identification on each of the curve data respectively, and when abnormal curve data and corresponding abnormal phase intervals are identified, determining the amplitude and discharge times at the same position as the abnormal phase interval and at the abnormal phase interval in each of the non-abnormal curve data as the curve data to be fitted, and performing curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain a curve to be evaluated;

[0104] Each preset defect and the corresponding graph feature are obtained, and a comparison process is performed based on the graph feature corresponding to each preset defect and the curve to be evaluated to obtain the partial discharge monitoring result of the monitoring cable joint.

[0105] It is worth noting that in the above-mentioned embodiment of the cable joint partial discharge online monitoring method system, the various units and modules included are only divided according to functional logic, but are not limited to the above-mentioned division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional units are only for the convenience of distinguishing each other, and are not used to limit the protection scope of the embodiments of the present invention.

[0106] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the embodiments of the present invention are not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the embodiments of the present invention. Therefore, although the embodiments of the present invention are described in more detail through the above embodiments, the embodiments of the present invention are not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the embodiments of the present invention, and the scope of the embodiments of the present invention is determined by the scope of the appended claims.

Claims

1. A method for online monitoring of partial discharge of cable joints, characterized in that: include: Receive a pulse current signal of a monitoring cable joint uploaded by a monitoring terminal, perform signal processing on the pulse current signal and generate a partial discharge spectrum, split the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle in the preset period; Performing abnormal identification on each of the curve data respectively, and when abnormal curve data and corresponding abnormal phase intervals are identified, determining the amplitude and discharge times at the same position as the abnormal phase interval and at the abnormal phase interval in each of the non-abnormal curve data as the curve data to be fitted, and performing curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain a curve to be evaluated; Each preset defect and the corresponding graph feature are obtained, and a comparison process is performed based on the graph feature corresponding to each preset defect and the curve to be evaluated to obtain the partial discharge monitoring result of the monitoring cable joint.

2. The method for online monitoring of partial discharge of cable joints according to claim 1, characterized in that: The performing abnormality identification on each of the curve data respectively includes: The amplitude and the number of discharges corresponding to each phase angle in the curve data are compared with the corresponding preset comparison values ​​in sequence, and whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data are determined according to the comparison results.

3. The method for online monitoring of partial discharge of cable joints according to claim 2, characterized in that: The determining, according to the comparison processing result, whether the curve data is abnormal curve data and the abnormal phase interval of the abnormal curve data comprises: Determine whether there are continuous amplitudes greater than a preset number or discharge times greater than the corresponding preset comparison values ​​in the comparison processing results. If so, determine the curve data as abnormal curve data, and determine the range of phase angles corresponding to each of the continuous preset number of amplitudes or discharge times as an abnormal phase interval.

4. The on-line monitoring method for partial discharge of a cable joint according to any one of claims 1 to 3, characterized in that: The step of performing curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain the curve to be evaluated includes: The amplitude average value and the discharge number average value at each same phase angle position in each of the curve data to be fitted are calculated, and the curve to be evaluated is generated according to the correspondence between each of the amplitude average value and each of the discharge number average value and the abnormal phase interval.

5. The on-line monitoring method for partial discharge of cable joints according to any one of claims 1 to 3, characterized in that: The spectrum features include characteristic phase intervals, amplitude features, and discharge features. The partial discharge monitoring result of the monitoring cable joint is obtained by comparing the spectrum features corresponding to each of the preset defects with the curve to be evaluated, including: Matching the abnormal phase interval corresponding to the curve to be evaluated with the characteristic phase interval in each of the spectrum features, and determining each of the spectrum features that successfully matches as the spectrum feature to be compared; The partial discharge monitoring result of the monitoring cable joint is obtained by comparing the amplitude characteristics and the discharge characteristics in the to-be-compared spectrum characteristics with the to-be-evaluated curve.

6. The method for online monitoring of partial discharge of cable joints according to claim 5, characterized in that: The amplitude feature includes an amplitude feature range and an amplitude feature change trend, the discharge feature includes a discharge number feature range, and the partial discharge monitoring result of the monitoring cable joint is obtained by comparing the amplitude feature and the discharge feature in the to-be-compared graph feature with the to-be-evaluated curve, including: Identify the amplitude range, amplitude change trend and discharge number range in the curve to be evaluated, and compare the amplitude range, amplitude change trend and discharge number range with the amplitude characteristic range, amplitude characteristic change trend and discharge number characteristic range respectively; In the case that all the comparisons are successful, it is determined that partial discharge exists in the monitoring cable joint, and the preset defect corresponding to the atlas feature to be compared is determined as the defect of the monitoring cable joint.

7. The on-line monitoring method for partial discharge of a cable joint according to any one of claims 1 to 3, characterized in that: The partial discharge spectrum is split according to a preset period to obtain a plurality of curve data, including: The partial discharge spectrum is split once every preset period to obtain a plurality of sub-partial discharge spectra, and the amplitude and discharge times corresponding to each phase angle in each of the sub-partial discharge spectra are identified and determined as corresponding curve data.

8. An online monitoring system for partial discharge of cable joints, characterized in that: include: A partial discharge spectrum generating module is used to receive the pulse current signal of the monitoring cable joint uploaded by the monitoring terminal, perform signal processing on the pulse current signal and generate a partial discharge spectrum; A spectrum splitting and processing module, used for splitting the partial discharge spectrum according to a preset period to obtain a plurality of curve data, wherein the curve data includes the amplitude and the number of discharges corresponding to each phase angle in the preset period; An abnormality identification module, used for identifying abnormalities of each of the curve data; A curve fitting module is used to, when abnormal curve data and corresponding abnormal phase intervals are identified, determine the amplitude and discharge number at the same position as the abnormal phase interval and at the abnormal phase interval in each non-abnormal curve data as the curve data to be fitted, and perform curve fitting based on each of the curve data to be fitted and the abnormal phase interval to obtain a curve to be evaluated; The monitoring result determination module is used to obtain each preset defect and the corresponding spectrum feature, and to obtain the partial discharge monitoring result of the monitoring cable joint based on the comparison processing of the spectrum features corresponding to each preset defect and the curve to be evaluated.

9. An online monitoring device for partial discharge of a cable joint, the device comprising: one or more processors; A storage device for storing one or more programs, when the one or more programs are executed by the one or more processors, the one or more processors implement the on-line monitoring method for partial discharge of cable joints as described in any one of claims 1-7.

10. A storage medium storing computer executable instructions, wherein the computer executable instructions are used to execute the on-line monitoring method for partial discharge of a cable joint according to any one of claims 1 to 7 when executed by a computer processor.

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