A method for fault location in power distribution cables based on electrical signal analysis

Abstract

The present application relates to the field of cable fault detection, and more particularly to a power distribution cable fault positioning method based on electric signal analysis, comprising: determining the cable analysis state of each abnormal response point according to the interval monitoring execution index, and determining whether to perform initial interference analysis or execution evaluation analysis according to the cable analysis state of the abnormal response point; when performing initial interference analysis, determining whether to perform interference compensation processing and range optimization processing for each abnormal response point according to the reference feature matching index; determining whether to perform channel filtering according to the interference effect evaluation index, and determining whether to perform compensation collection processing for each cable monitoring interval according to the interference compensation coefficient; when performing execution evaluation analysis, determining whether to perform redundant distribution prompting for each abnormal response point according to the execution redundancy parameter. The present application can ensure the efficiency of cable fault positioning while reducing the requirements for monitoring point layout.

Description

Technical Field

[0001] This invention relates to the field of cable fault detection, and in particular to a method for locating faults in power distribution cables based on electrical signal analysis. Background Technology

[0002] Because underground power distribution cables are exposed to the underground environment for extended periods, their insulation layers are susceptible to damage from external environmental factors and usage time, leading to grounding faults. Therefore, accurately and efficiently locating cable faults is crucial for ensuring the stable operation of the power grid and reliable power supply. Existing fault location methods for power distribution cables often rely on multi-terminal time difference relationships and two-terminal distance measurement. However, the efficiency and accuracy of these methods are highly dependent on the density, location rationality, and scenario adaptability of monitoring points. This means that the efficiency of fault location for power distribution cables largely depends on the layout of monitoring points, resulting in the cable fault location analysis process being unable to effectively adapt to actual working scenarios. Therefore, determining a targeted fault location analysis method based on the actual conditions of the power distribution cable network, which can ensure cable fault location efficiency and accuracy while reducing the requirements for monitoring point density and deployment environment, is a problem that urgently needs to be solved by those skilled in the art.

[0003] Chinese Patent Publication No. CN118731578A discloses a method for locating power cable faults and an intelligent power distribution system. The method involves collecting current signals from various fault monitoring nodes of a target power cable in an intelligent power distribution system; determining the signal association feature sequence of each fault monitoring node; further determining the adjacent fault discrimination quantity of the signal at each fault monitoring node; identifying the latent fault range of the target power cable based on each monitoring time span and all adjacent fault discrimination quantities; determining the fault response point in the high-frequency band and the non-fault response point in the low-frequency band of the target power cable when subjected to pulse excitation based on the fault response coefficient and the latent fault range; and determining the explicit fault range of the target power cable based on the fault response point and the non-fault response point. However, the above solution has the following drawback: it fails to determine a targeted fault location analysis method based on the actual situation of the power distribution cable network, resulting in an inability to guarantee the efficiency of cable fault location. Summary of the Invention

[0004] Therefore, this invention provides a method for locating faults in power distribution cables based on electrical signal analysis, which overcomes the problem that existing technologies fail to determine a targeted fault location analysis method based on the actual situation of the power distribution cable network, resulting in the inability to guarantee the efficiency of cable fault location.

[0005] To achieve the above objectives, the present invention provides a method for fault location of power distribution cables based on electrical signal analysis, comprising:

[0006] The cable analysis status of each abnormal response point is determined based on the interval monitoring execution index, and whether initial interference analysis or execution evaluation analysis should be performed for the corresponding abnormal response point is determined based on the cable analysis status of the abnormal response point.

[0007] During the initial interferometric analysis, the reference feature matching index is used to determine whether to perform interferometric compensation and range optimization for each abnormal response point.

[0008] When performing range optimization, it is determined whether to perform channel filtering for each abnormal response point based on the interference effect assessment index. The interference effect assessment index is determined based on the cable monitoring interval corresponding to each cable monitoring point.

[0009] When performing interference compensation processing, the setting method of the interference compensation coefficient is determined according to the matching evaluation difference index, and the interference compensation coefficient is used to determine whether to perform compensation data acquisition processing for each cable monitoring interval.

[0010] When performing execution evaluation and analysis, determine whether to provide redundancy distribution prompts for each abnormal response point based on the execution redundancy parameters.

[0011] Furthermore, the abnormal response point is a cable monitoring point that receives any abnormal traveling wave signal;

[0012] The abnormal traveling wave signal is a traveling wave analysis signal whose abnormality assessment index is greater than the preset abnormality assessment index. The abnormality assessment index is determined based on the difference index of each baseline assessment parameter.

[0013] Furthermore, the cable analysis status categories include Class I cable analysis status and Class II cable analysis status;

[0014] The abnormal response points in the first type of cable analysis state are those where the interval monitoring execution index is greater than the preset interval monitoring execution index.

[0015] An abnormal response point in the second-class cable analysis state is an abnormal response point where the interval monitoring execution index is less than or equal to the preset interval monitoring execution index.

[0016] Furthermore, if an abnormal response point exists under Category II cable analysis, an initial interferometry analysis is performed on that abnormal response point.

[0017] The reference feature matching index is determined based on the various traveling wave matching feature parameters of each abnormal traveling wave signal.

[0018] Furthermore, if the reference feature matching index of an abnormal response point in the Class II cable analysis state is greater than the preset reference feature matching index, then range optimization processing is performed on that abnormal response point.

[0019] Based on the cable monitoring interval corresponding to the co-monitoring point where the abnormal response point exists, an interference effect assessment index is determined to determine whether channel filtering should be performed for the abnormal response point.

[0020] Furthermore, if the interference evaluation index of an abnormal response point is greater than the preset interference evaluation index, then channel filtering is performed on that abnormal response point.

[0021] The filtering execution coefficient for each cable monitoring interval is determined based on the interval execution index and the execution response index. Channel filtering is performed for cable monitoring intervals whose filtering execution coefficient is greater than the preset filtering execution coefficient.

[0022] Furthermore, if the reference characteristic matching index of an abnormal response point in the Class II cable analysis state is less than or equal to the preset reference characteristic matching index, then interference compensation processing is performed on the abnormal response point.

[0023] Determine whether to perform compensation data acquisition and processing for the abnormal response point based on the interference compensation coefficient;

[0024] If the interference compensation coefficient is greater than the preset interference compensation coefficient, compensation acquisition processing will be performed on the abnormal response point.

[0025] Furthermore, the setting method of the interference compensation coefficient is determined based on the matching evaluation difference index, wherein,

[0026] If the matching evaluation difference index is greater than the preset matching evaluation difference index, the interference compensation coefficient is determined based on the matching evaluation difference index.

[0027] If the matching evaluation difference index is less than or equal to the preset matching evaluation difference index, the interference compensation coefficient is determined based on the reference feature matching index.

[0028] Furthermore, if an abnormal response point is in a Class I cable analysis state, an evaluation analysis will be performed on that abnormal response point.

[0029] Furthermore, if the execution redundancy parameter of an abnormal response point in a cable analysis state is greater than the preset execution redundancy parameter, a redundancy distribution prompt will be given for that abnormal response point.

[0030] Compared with the prior art, the beneficial effects of the present invention are that the technical solution of the present invention analyzes each cable monitoring point that has acquired abnormal traveling wave signals to determine the actual state of each cable monitoring point, thereby determining the targeted processing method for the subsequent analysis process. This makes the analysis and processing process of each abnormal response point more in line with the actual working scenario, thereby reducing the degree of influence of interference information on the fault location analysis process. The present invention improves the efficiency of fault location analysis for power distribution cables.

[0031] Furthermore, in this invention, the cable analysis status of each abnormal response point is determined based on the interval monitoring execution index. The interval monitoring execution index characterizes the degree of clarity of the abnormal traveling wave signal obtained by each abnormal response point for fault location, that is, the degree of reference effectiveness for fault location. Based on the cable analysis status, it is determined whether to perform initial interference analysis or performance evaluation analysis, and targeted settings are made for subsequent analysis processes to avoid the inefficiency caused by uniform analysis of all abnormal response points.

[0032] Furthermore, in this invention, for abnormal response points in the analysis state of Class II cables, since the wavefront steepness of the abnormal traveling wave signals acquired at such abnormal response points is weak and the pulse polarity between abnormal traveling wave signals fluctuates, it indicates that the directivity of the abnormal traveling wave signals acquired at these abnormal response points is relatively poor. A preliminary interferometric analysis is performed on the acquired abnormal traveling wave signals to determine the current acquisition status of abnormal traveling wave signals and make targeted optimizations, thereby reducing the deployment requirements of monitoring points in the fault location analysis process while ensuring the efficiency of fault location analysis.

[0033] Furthermore, in this invention, the reference feature matching index is used to determine whether interference compensation processing and range optimization processing should be performed on each abnormal response point. The reference feature matching index is used to characterize the overall matching degree between the acquired abnormal traveling wave signal and the existing benchmark fault traveling wave signal. This allows for the assessment of the interference level experienced by the traveling wave signal during actual transmission, thereby enabling targeted processing of the abnormal response points, improving the quality of the acquired abnormal traveling wave signal, and thus improving the directivity of the acquired abnormal traveling wave signal. This reduces the requirements for the deployment of cable monitoring points.

[0034] Furthermore, in this invention, for abnormal response points in a cable analysis state, since the abnormal traveling wave signals obtained from such abnormal response points have a high degree of directional clarity for the fault area, the fault area corresponding to the abnormal traveling wave signal can be effectively determined without further analysis. For such abnormal response points, an execution evaluation analysis is performed to determine whether there is a significant overlap in the execution functions of such abnormal response points in the actual monitoring point layout scheme, so as to determine whether to issue a reminder to the user and avoid resource waste during the actual monitoring process. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the power distribution cable fault location method based on electrical signal analysis according to the present invention;

[0036] Figure 2 This is a flowchart illustrating the cable analysis status of each abnormal response point based on the interval monitoring execution index, as per the present invention.

[0037] Figure 3 This is a flowchart illustrating the present invention for determining whether to perform initial interference analysis or evaluation analysis on the corresponding abnormal response point based on the current cable analysis state.

[0038] Figure 4 This is a flowchart illustrating the process of determining whether to perform interference compensation and range optimization for each abnormal response point based on a reference feature matching index, according to the present invention. Detailed Implementation

[0039] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0040] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0041] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0042] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] Please see Figures 1 to 4 As shown, the present invention provides a method for fault location of power distribution cables based on electrical signal analysis, comprising:

[0044] The cable analysis status of each abnormal response point is determined based on the interval monitoring execution index, and whether initial interference analysis or execution evaluation analysis should be performed for the corresponding abnormal response point is determined based on the cable analysis status of the abnormal response point.

[0045] During the initial interferometric analysis, the reference feature matching index is used to determine whether to perform interferometric compensation and range optimization for each abnormal response point.

[0046] When performing range optimization, it is determined whether to perform channel filtering for each abnormal response point based on the interference effect assessment index. The interference effect assessment index is determined based on the cable monitoring interval corresponding to each cable monitoring point.

[0047] When performing interference compensation processing, the setting method of the interference compensation coefficient is determined according to the matching evaluation difference index, and the interference compensation coefficient is used to determine whether to perform compensation data acquisition processing for each cable monitoring interval.

[0048] When performing execution evaluation and analysis, determine whether to provide redundancy distribution prompts for each abnormal response point based on the execution redundancy parameters.

[0049] This invention is used to set up a targeted cable fault location analysis process based on the actual layout of monitoring points in the underground power distribution cable network. This allows the fault location analysis process to adapt to actual working conditions, avoiding the limitations of a single fault location analysis method whose efficiency and accuracy are restricted by the layout of monitoring points. The underground power distribution cable network targeted for fault location analysis is denoted as the target monitoring network. In this invention, the power distribution cables existing in the target monitoring network are denoted as fault monitoring cables. The target monitoring network also contains several cable monitoring points used to collect traveling wave analysis signals and identify abnormal traveling wave signals. This invention does not limit the composition of the monitoring tools corresponding to the cable monitoring points or the sampling frequency, but the cable monitoring points need to be able to acquire the traveling wave analysis signals of the power distribution cables and analyze the acquired traveling wave analysis signals. The monitoring tools corresponding to the cable monitoring points can mainly consist of a high-frequency current sensor, a signal conditioning unit, a data acquisition and FPGA preprocessing unit, a host computer, and analysis software. The high-frequency current sensor is installed using a through-core method to sense the high-frequency current signal generated when partial discharge occurs. The signal conditioning unit has functions for amplifying, filtering, and A / D converting partial discharge high-frequency current signals and synchronization signals. The conditioned signals are acquired and analyzed by the data acquisition and FPGA preprocessing unit. Cable monitoring intervals are determined based on the cable monitoring points in the target monitoring network. Each cable monitoring interval represents a portion of the fault-monitored cables, and cable monitoring points exist at both ends of any cable monitoring interval. Each cable monitoring point has at least one cable monitoring interval. For any cable monitoring point, the cable monitoring interval corresponds to a portion of the distribution cable. The fault traveling wave signal generated at any location within the corresponding cable monitoring interval can be acquired at that cable monitoring point.

[0050] This invention utilizes several fault analysis records. Each fault analysis record contains at least one abnormal assessment index, interval monitoring execution index, reference feature matching index, interference effect assessment index, filtering execution coefficient, interference compensation coefficient, matching assessment difference index, and execution redundancy parameters during the fault location monitoring process of the power distribution cable network. Each fault analysis record also has a corresponding qualified mark, which indicates whether the location analysis efficiency of the fault location monitoring of the power distribution cable network meets the user's requirements.

[0051] Specifically, the abnormal response point is a cable monitoring point that receives any abnormal traveling wave signal;

[0052] The abnormal traveling wave signal is a traveling wave analysis signal whose abnormality assessment index is greater than the preset abnormality assessment index. The abnormality assessment index is determined based on the difference index of each baseline assessment parameter.

[0053] In this invention, for any traveling wave analysis signal acquired at a single cable monitoring point, the anomaly assessment index is the sum of the difference indices of each baseline assessment parameter. For a single baseline assessment parameter, the difference index = (the value of the baseline assessment parameter determined for the traveling wave analysis signal - the baseline standard value of the baseline assessment parameter) / the baseline standard value of the baseline assessment parameter. The baseline standard values ​​of each baseline assessment parameter can be set by the user according to the actual working scenario, which is easily understood by those skilled in the art. A baseline standard value of 0.3 is provided for the high-frequency proportion parameter. The categories of baseline assessment parameters used to determine the anomaly assessment index in this invention include: signal amplitude parameters and high-frequency proportion parameters. The signal amplitude parameter is the amplitude of the acquired traveling wave analysis signal. The high-frequency proportion parameter = the signal energy corresponding to the high-frequency interval in the traveling wave analysis signal / the signal energy of the traveling wave analysis signal. The numerical range of the high-frequency interval can be set by the user according to the actual situation. How to determine the numerical range of the high-frequency interval and how to determine the high-frequency proportion parameter based on Fourier transform are contents that are already mastered by those skilled in the art, and will not be elaborated here. Users can also add other categories of baseline assessment parameters according to the actual situation.

[0054] The value of the preset anomaly assessment index can be determined by the user based on the actual working scenario. For example, the user can set it based on the fault analysis record. The higher the user's requirement for the location analysis efficiency of fault location monitoring in the power distribution cable network, the smaller the value of the preset anomaly assessment index. A method for determining the value of the preset anomaly assessment index is provided, which is the minimum value of the anomaly assessment index of the abnormal traveling wave signal in the fault analysis record that meets the user's requirement for the location analysis efficiency of fault location monitoring in the power distribution cable network.

[0055] Specifically, the cable analysis status categories include Class I cable analysis status and Class II cable analysis status;

[0056] The abnormal response points in the first type of cable analysis state are those where the interval monitoring execution index is greater than the preset interval monitoring execution index.

[0057] An abnormal response point in the second-class cable analysis state is an abnormal response point where the interval monitoring execution index is less than or equal to the preset interval monitoring execution index.

[0058] For a single abnormal response point, the interval monitoring execution index is the sum of the traveling wave steepness index and the abnormal traveling wave stability index. The traveling wave steepness index is the average wavefront steepness of the abnormal traveling wave signals acquired at that abnormal response point during the response analysis phase. For any abnormal traveling wave signal acquired at that abnormal response point during the response analysis phase, the wavefront steepness is defined as the interval between the moment when the amplitude first reaches 10% of the maximum amplitude of the abnormal traveling wave signal and the moment when the amplitude first reaches 90% of the maximum amplitude of the abnormal traveling wave signal, and the duration of the received abnormal traveling wave signal is defined as the interval between the moment when the amplitude first reaches 10% of the maximum amplitude of the abnormal traveling wave signal. The unit of measurement for the interval can be ns. The moment when the first abnormal traveling wave signal of the abnormal response point is acquired is recorded as the response execution moment. The abnormal traveling wave stability index is defined as the deviation polarity during the response analysis phase. The number of signals / the number of dominant polarity signals in the response analysis phase. For any abnormal traveling wave signal obtained at the abnormal response point in the response analysis phase, if the pulse polarity of the abnormal traveling wave signal is the dominant pulse polarity, then the abnormal traveling wave signal is recorded as the dominant polarity signal; otherwise, the abnormal traveling wave signal is recorded as the deviation polarity signal. The pulse polarity with the most existing abnormal traveling wave signals in the response analysis phase is recorded as the dominant pulse polarity. The start time of the response analysis phase is the response execution time. The duration of the response analysis phase can be determined by the user according to the actual working scenario. A value for the duration of the response analysis phase is provided. The duration of the response analysis phase is 5 seconds. How to determine the pulse polarity of the traveling wave signal in the actual monitoring process is a topic already mastered by those skilled in the art and will not be elaborated here.

[0059] The value of the preset interval monitoring execution index can be determined by the user according to the actual working scenario. For example, the user can set it according to the fault analysis record. The higher the user's requirement for the location analysis efficiency of fault location monitoring of the power distribution cable network, the smaller the value of the preset interval monitoring execution index. A method for determining the value of the preset interval monitoring execution index is provided, which is the maximum value of the interval monitoring execution index of the abnormal response point in the fault analysis record that meets the user's requirement for the location analysis efficiency of fault location monitoring of the power distribution cable network and is in the second-class cable analysis state.

[0060] Specifically, if an abnormal response point exists under Category II cable analysis, an initial interferometry analysis is performed on that abnormal response point.

[0061] The reference feature matching index is determined based on the various traveling wave matching feature parameters of each abnormal traveling wave signal.

[0062] For a single abnormal response point, if the abnormal response point is in the Class II cable analysis state, it indicates that the wavefront steepness of the abnormal traveling wave signal obtained at the abnormal response point is weak and the pulse polarity between the abnormal traveling wave signals fluctuates. This indicates that the directivity of the abnormal traveling wave signal obtained at the abnormal response point is relatively poor. It is necessary to perform preliminary interferometry analysis based on the obtained abnormal traveling wave signal to determine the interference factors or optimize the analysis range.

[0063] For a single abnormal response point in the Class II cable analysis state, the reference feature matching index is the average of the feature matching indices of the abnormal traveling wave signals acquired at that abnormal response point during the response analysis phase. For any abnormal traveling wave signal acquired at that abnormal response point during the response analysis phase, the feature matching index is the maximum value of the parameter matching index between the abnormal traveling wave signal and the reference fault traveling wave signals of each category. For a single abnormal traveling wave signal and any category of reference fault traveling wave signal, the parameter matching index is the average of the parameter matching degrees between the abnormal traveling wave signal and the reference fault traveling wave signal of the above categories. For a single traveling wave matching feature parameter, the parameter matching degree = the reference value determined by the reference fault traveling wave signal of that category for that traveling wave matching feature parameter / |the The reference value of the reference fault traveling wave signal for a given category is the reference value of the abnormal traveling wave signal for that same traveling wave matching feature parameter ||. The reference values ​​of each traveling wave matching feature parameter corresponding to the reference fault traveling wave signal for each category can be set by the user according to the actual working scenario. For example, for a single category of reference fault traveling wave signal, the user can use the average value of the reference fault traveling wave signal values ​​for that category determined in the fault analysis record as the reference value. In this invention, the category of the traveling wave matching feature parameter for determining the parameter matching index is not specifically limited. The categories of the traveling wave matching feature parameter for determining the parameter matching index include, but are not limited to, pulse width and attenuation coefficient. The reference fault traveling wave signal for each category is an abnormal traveling wave signal obtained by determining the corresponding fault category.

[0064] Specifically, if the reference feature matching index of an abnormal response point in the Class II cable analysis state is greater than the preset reference feature matching index, then range optimization processing is performed on that abnormal response point.

[0065] Based on the cable monitoring interval corresponding to the co-monitoring point where the abnormal response point exists, an interference effect assessment index is determined to determine whether channel filtering should be performed for the abnormal response point.

[0066] Specifically, if the interference evaluation index of an abnormal response point is greater than the preset interference evaluation index, then channel filtering is performed on that abnormal response point.

[0067] The filtering execution coefficient for each cable monitoring interval is determined based on the interval execution index and the execution response index. Channel filtering is performed for cable monitoring intervals whose filtering execution coefficient is greater than the preset filtering execution coefficient.

[0068] Among them, for a single abnormal response point in the analysis state of a Class II cable, if the reference feature matching index of the abnormal response point is greater than the preset reference feature matching index, it indicates that the directional clarity of the abnormal traveling wave signal obtained by the abnormal response point is relatively poor. Preliminary analysis determines that the overall matching degree between the obtained abnormal traveling wave signal and the existing benchmark fault traveling wave signal is good, which indicates that the interference of the currently obtained abnormal traveling wave signal itself is weak. The evaluation is conducted to determine whether there is cross-interference between abnormal traveling wave signals of multiple types of faults or multiple sources.

[0069] For a single abnormal response point, the collaborative monitoring point is a cable monitoring point that overlaps with the cable monitoring interval of the abnormal response point. The interference effect evaluation index is the average of the effect evaluation indices of each collaborative monitoring point of the abnormal response point. For a single collaborative monitoring point, the effect evaluation index = the number of identical cable monitoring intervals corresponding to the abnormal traveling wave signals acquired by the collaborative monitoring point and the abnormal response point / the number of cable monitoring intervals corresponding to the abnormal traveling wave signals acquired by the abnormal response point. For a single cable monitoring interval, the filtering execution coefficient is the sum of the interval execution index and the execution response index of the cable monitoring interval. The interval execution index = the number of cable monitoring points corresponding to the cable monitoring interval / the number of cable monitoring points in the target monitoring network. The execution response index is the average of the number of abnormal traveling wave signals received by each cable monitoring point corresponding to the cable monitoring interval. For cable monitoring intervals with a filtering execution coefficient greater than the preset filtering execution coefficient, channel filtering is performed, that is, the abnormal response point stops acquiring the traveling wave signals generated by the cable monitoring interval.

[0070] The values ​​of the preset reference feature matching index, the preset interference effect evaluation index, and the preset filtering execution coefficient can be determined by the user according to the actual working scenario. For example, the user can set them based on fault analysis records. The higher the user's requirement for the location analysis efficiency of fault location monitoring in the power distribution cable network, the smaller the value of the preset interference effect evaluation index and the smaller the value of the preset filtering execution coefficient. A method for determining the value of the preset reference feature matching index is provided, where fault analysis records that perform range optimization processing on abnormal response points are recorded as matching reference records, and the matching reference records that meet the user's requirements for the location analysis efficiency of fault location monitoring in the power distribution cable network are used as reference records. The minimum value of the feature matching index is denoted as the preset reference feature matching index. A method for determining the preset interference effect evaluation index is provided. Fault analysis records that perform channel filtering for abnormal response points are denoted as filtering reference records. The minimum value of the interference effect evaluation index in the filtering reference records that meets the user's location analysis efficiency requirements for fault location monitoring of power distribution cable networks is denoted as the preset interference effect evaluation index. A method for determining the preset filtering execution coefficient is provided. The minimum value of the filtering execution coefficient of the cable monitoring interval that performs channel filtering in the fault analysis records that meets the user's location analysis efficiency requirements for fault location monitoring of power distribution cable networks is denoted as the preset filtering execution coefficient.

[0071] Specifically, if the reference characteristic matching index of an abnormal response point in the Class II cable analysis state is less than or equal to the preset reference characteristic matching index, then interference compensation processing is performed on that abnormal response point.

[0072] Determine whether to perform compensation data acquisition and processing for the abnormal response point based on the interference compensation coefficient;

[0073] If the interference compensation coefficient is greater than the preset interference compensation coefficient, compensation acquisition processing will be performed on the abnormal response point.

[0074] Specifically, for a single abnormal response point in the Class II cable analysis state, if the reference characteristic matching index of the abnormal response point is less than or equal to the preset reference characteristic matching index, it indicates that the directional accuracy of the abnormal traveling wave signal acquired at that abnormal response point is relatively poor. Preliminary analysis determines that the acquired abnormal traveling wave signal has a poor matching degree with the existing benchmark fault traveling wave signal, further indicating that the acquired abnormal traveling wave signal is affected to a certain extent during its own transmission, resulting in a poor reference role for the acquired abnormal traveling wave signal in the actual analysis process. If the interference compensation coefficient is greater than the preset interference compensation coefficient, then... It is evident that the transmission loss at the abnormal response point is significant during the acquisition of the corresponding traveling wave signal. Therefore, compensation acquisition processing is required for this abnormal response point. Compensation acquisition processing involves increasing the sampling point density or extending the sampling time window during the acquisition of the traveling wave signal to obtain a more complete traveling wave waveform. The increase in sampling point density or the increase in the duration of the sampling time window is positively correlated with the interference compensation coefficient. How to increase the sampling point density or extend the sampling time window during the acquisition of the traveling wave signal to adjust the waveform quality is a topic already known to those skilled in the art and will not be elaborated here.

[0075] The value of the preset interference compensation coefficient can be set by the user according to the actual working scenario. For example, the user can set it according to the fault analysis record. The higher the user's requirement for the positioning analysis efficiency of fault location monitoring of the power distribution cable network, the smaller the value of the preset interference compensation coefficient. A method for setting the value of the preset interference compensation coefficient is provided, in which the fault analysis record for compensation acquisition and processing of the cable monitoring interval is recorded as the compensation reference record, and the minimum value of the interference compensation coefficient in the compensation reference record that meets the user's requirement for the positioning analysis efficiency of fault location monitoring of the power distribution cable network is recorded as the preset interference compensation coefficient.

[0076] Specifically, the setting method of the interference compensation coefficient is determined based on the matching evaluation difference index, wherein,

[0077] If the matching evaluation difference index is greater than the preset matching evaluation difference index, the interference compensation coefficient is determined based on the matching evaluation difference index.

[0078] If the matching evaluation difference index is less than or equal to the preset matching evaluation difference index, the interference compensation coefficient is determined based on the reference feature matching index.

[0079] Specifically, for a single abnormal response point, the matching evaluation difference index is calculated as: standard deviation between the characteristic matching indices of the abnormal traveling wave signals acquired at the abnormal response point during the response analysis phase / average value of the characteristic matching indices of the abnormal traveling wave signals acquired at the abnormal response point during the response analysis phase. The value of the preset matching evaluation difference index can be set by the user according to the actual working scenario. For example, the user can set it based on the fault analysis records. A method for determining the value of the preset matching evaluation difference index is provided, where the fault analysis records that determine the interference compensation coefficient based on the matching evaluation difference index are recorded as difference reference records, and the minimum value of the matching evaluation difference index in the difference reference records that meets the user's positioning analysis efficiency requirements for fault location monitoring of the power distribution cable network is recorded as the preset matching evaluation difference index.

[0080] If the matching evaluation difference index is greater than the preset matching evaluation difference index, it indicates that although the overall matching degree of the abnormal traveling wave signal obtained is poor with the existing benchmark fault traveling wave signal, there is a high matching degree of some abnormal traveling wave signals. This indicates that the abnormal traveling wave signal obtained originates from multiple corresponding fault monitoring intervals and only some fault monitoring intervals are affected in the transmission process of the traveling wave signal. At this time, the interference compensation coefficient is determined by the matching evaluation difference index to characterize the degree of influence of the partially affected fault monitoring intervals. The determined matching evaluation difference index is normalized, and the interference compensation coefficient is positively correlated with the normalized matching evaluation difference index.

[0081] If the matching evaluation difference index is less than or equal to the preset matching evaluation difference index, it indicates that the matching degree between the currently acquired abnormal traveling wave signal and the existing benchmark fault traveling wave signal is generally poor. This further indicates that the acquisition process of the currently acquired abnormal traveling wave signal is affected to a certain extent by the acquisition process of the traveling wave signal monitored in its corresponding fault monitoring interval. At this time, the interference compensation coefficient is determined by the reference feature matching index to characterize the overall degree of influence. The reference feature matching index is normalized, and the interference compensation coefficient is negatively correlated with the normalized reference feature matching index.

[0082] Specifically, if an abnormal response point is in a Class I cable analysis state, an evaluation analysis will be performed on that abnormal response point.

[0083] Specifically, if the execution redundancy parameter of an abnormal response point in a cable analysis state is greater than the preset execution redundancy parameter, a redundancy distribution prompt will be given for that abnormal response point.

[0084] Specifically, for a single abnormal response point, if the abnormal response point is in a Class I cable analysis state, it indicates that the abnormal traveling wave signal acquired by the abnormal response point has a high wavefront steepness and the pulse polarity between abnormal traveling wave signals is relatively stable. This indicates that the directionality of the abnormal traveling wave signal acquired by the abnormal response point is relatively clear, and fault location can be performed based on the acquired abnormal traveling wave signal. Users can determine the specific location method according to the actual working scenario. For example, users can use the single-end traveling wave location method or the double-end traveling wave location method to locate the fault area. How to perform fault location based on the acquired abnormal traveling wave signal to determine the fault response area is a content that is easy for those skilled in the art to understand, and will not be elaborated here. By analyzing the current acquisition of traveling wave signals by the abnormal response point, it is determined whether there is redundancy in the setting of cable monitoring points.

[0085] For a single abnormal response point, the execution redundancy parameter is the sum of the overlap response ratio index and the reference overlap response index of that abnormal response point. The overlap response ratio index = the number of overlapping response points of that abnormal response point / the number of cable monitoring points in the target monitoring network. The reference overlap response index is the average of the overlap response indices of all overlapping response points of that abnormal response point. The overlapping response point is an abnormal response point that overlaps with the fault response area determined by the abnormal response point. For any two abnormal response points that have completed the determination of fault response areas, the overlap response index = the number of fault response areas that overlap between the two abnormal response points / the number of fault response areas determined by the two abnormal response points.

[0086] If the execution redundancy parameter of an abnormal response point is greater than the preset execution redundancy parameter, it indicates that the abnormal response point has overlapping monitoring tasks with other cable monitoring points in the current monitoring point deployment scheme. A redundancy distribution prompt is sent to the user for this abnormal response point, suggesting whether to disable this type of cable monitoring point to avoid resource consumption. The value of the preset execution redundancy parameter can be set by the user according to the actual working scenario. For example, the user can set it based on fault analysis records. The higher the user's requirement for the location analysis efficiency of fault location monitoring in the power distribution cable network, the smaller the value of the preset execution redundancy parameter. A method for determining the preset execution redundancy parameter is provided, where the fault analysis records that provide redundancy distribution prompts for abnormal response points are recorded as redundancy reference records. Another method is provided, where the minimum value of the execution redundancy parameter in the redundancy reference records that meets the user's location analysis efficiency requirements for fault location monitoring in the power distribution cable network is recorded as the preset execution redundancy parameter.

[0087] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for locating a fault in a power distribution cable based on analysis of electrical signals, characterized by, The method comprises the following steps: determining the cable analysis state of each abnormal response point according to the interval monitoring execution index, and determining whether to perform initial interference analysis or evaluation analysis on the corresponding abnormal response point according to the cable analysis state of the abnormal response point; when the cable analysis state is type II, performing initial interference analysis, and determining whether to perform interference compensation processing and range optimization processing on each abnormal response point according to the reference feature matching index; when the reference feature matching index is greater than the preset reference feature matching index, performing range optimization processing, and determining whether to perform channel filtering on each abnormal response point according to the interference effect evaluation index, which is determined according to the cable monitoring intervals corresponding to each cable monitoring point; when the reference feature matching index is less than or equal to the preset reference feature matching index, performing interference compensation processing, determining the setting mode of the interference compensation coefficient according to the matching evaluation difference index, and determining whether to perform compensation collection processing on each cable monitoring interval according to whether the interference compensation coefficient is greater than the preset interference compensation coefficient; when the cable analysis state is type I, performing evaluation analysis, and determining whether to perform redundant distribution prompting on each abnormal response point according to whether the execution redundancy parameter is greater than the preset execution redundancy parameter; for a single abnormal response point, the interval monitoring execution index is the sum of the traveling wave steepness index and the abnormal traveling wave stability index, the traveling wave steepness index is the average value of the wave head steepness of the abnormal traveling wave signal obtained by the abnormal response point in the response analysis stage, the abnormal traveling wave stability index is the proportion of the number of deviation polarity signals in the number of dominant polarity signals in the response analysis stage, the execution redundancy parameter is the sum of the coincidence response proportion index and the reference coincidence response index, the coincidence response proportion index is the proportion of the number of coincidence response points existing in the target monitoring network to the number of cable monitoring points, and the reference coincidence response index is the average value of the coincidence response index of each coincidence response point of the abnormal response point; the categories of the cable analysis state include type I and type II; the abnormal response point in the type I cable analysis state is an abnormal response point with an interval monitoring execution index greater than a preset interval monitoring execution index; the abnormal response point in the type II cable analysis state is an abnormal response point with an interval monitoring execution index less than or equal to a preset interval monitoring execution index.

2. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 1, wherein, The abnormal response point is a cable monitoring point receiving any abnormal traveling wave signal. The abnormal traveling wave signal is a traveling wave analysis signal with an abnormal evaluation index greater than a preset abnormal evaluation index, and the abnormal evaluation index is determined according to the difference index of each baseline evaluation parameter.

3. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 1, wherein, If there is an abnormal response point in the type II cable analysis state, initial interference analysis is performed on the abnormal response point, wherein the reference feature matching index is determined according to each traveling wave matching feature parameter of each abnormal traveling wave signal.

4. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 3, wherein, If the reference feature matching index of the abnormal response point in the second cable analysis state is greater than the preset reference feature matching index, range optimization processing is performed on the abnormal response point, wherein, The interference effect evaluation index is determined based on the cable monitoring interval corresponding to the cooperative monitoring point where the abnormal response point exists, to determine whether to perform channel filtering on the abnormal response point.

5. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 4, wherein, If the interference effect evaluation index of the abnormal response point is greater than the preset interference effect evaluation index, channel filtering is performed on the abnormal response point. The filtering execution coefficient of each cable monitoring interval is determined according to the interval execution index and the execution response index, and channel filtering is performed on the cable monitoring interval with a filtering execution coefficient greater than the preset filtering execution coefficient.

6. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 5, wherein, If the reference feature matching index of the abnormal response point in the second cable analysis state is less than or equal to the preset reference feature matching index, interference compensation processing is performed on the abnormal response point, wherein, If the interference compensation coefficient is greater than the preset interference compensation coefficient, compensation collection processing is performed on the abnormal response point.

7. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 6, wherein, The setting mode of the interference compensation coefficient is determined according to the matching evaluation difference index, wherein, If the matching evaluation difference index is greater than the preset matching evaluation difference index, the interference compensation coefficient is determined according to the matching evaluation difference index. If the matching evaluation difference index is less than or equal to the preset matching evaluation difference index, the interference compensation coefficient is determined according to the reference feature matching index.

8. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 1 wherein, If the abnormal response point is in the first cable analysis state, execution evaluation analysis is performed on the abnormal response point.

9. The power distribution cable fault location method based on electrical signal analysis as claimed in claim 8, wherein, If the execution redundancy parameter of the abnormal response point in the first cable analysis state is greater than the preset execution redundancy parameter, redundancy distribution prompting is performed on the abnormal response point.

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