569results about "Fault location by pulse reflection methods" patented technology

The invention provides a power grid fault detection and positioning method and system for an intelligent power grid system. The method comprises the following steps: collecting a fault traveling wave signal when a power distribution line has a fault; preprocessing the fault traveling wave signal to obtain a preprocessed target fault traveling wave signal; carrying out traveling wave front edge detection on the target fault traveling wave signal, and determining the signal arrival time of the fault traveling wave signal; fault signal features are extracted from the target fault traveling wave signals through a frequency domain analysis method and a time domain analysis method; estimating the fault line characteristics of the fault line with the fault in combination with the fault signal characteristics and the signal arrival time; outputting the line type and the fault type of the fault line through a feature recognition model; selecting an optimal fault positioning algorithm by using a decision tree algorithm based on the line type and the fault type; and determining the line position of the fault line according to the target fault traveling wave signal by adopting an optimal fault positioning algorithm. The method has the effect of intelligently selecting the optimal positioning algorithm according to the line type.

A method for locating a high-impedance ground fault of a smart distribution network with topology change adaptation includes: acquiring a fault traveling wave sample within a specified time window after a fault occurs, and performing continuous wavelet transform on the fault traveling wave sample to obtain traveling wave full waveform feature information; establishing a graph structure of a power distribution network, obtaining a corresponding adjacency matrix, and obtaining node position and structure encoding information in the graph structure through graph random walk and graph Laplace transform; concatenating the node position, the structure encoding information and the traveling wave full waveform feature information to obtain a node feature, and inputting the node feature and an edge feature into the graph structure to establish a graph sample data set; constructing and training a Graph Transformer model; and calling the trained Graph Transformer model to locate a fault in to-be-detected sample data.

The invention discloses a cable insulation aging defect positioning evaluation self-diagnosis method, and belongs to the technical field of power system detection. According to the method, cable multi-dimensional data are obtained through a multi-band broadband dielectric spectrometer, a high-frequency pulse reflection tester and an optical time domain reflectometer, and features are extracted by applying wavelet transform, Fourier transform and a thermal diffusion model after digital processing. A deep convolutional neural network and a long and short term memory network are used for feature fusion and time sequence analysis, and a self-adaptive threshold algorithm and a fuzzy inference system are used for realizing defect accurate positioning and reliability scoring. According to the method, the accuracy and reliability of cable insulation aging defect diagnosis are improved, and intelligent self-diagnosis is realized.

The invention provides a traveling wave cable measurement sensing method and system based on a time-frequency domain combined reflection principle, and relates to the technical field of measurement, and the method comprises the steps: arranging a high-frequency signal transmitting device and a signal receiving device at one end of a traveling wave cable; establishing a time domain reflection function and a frequency domain reflection function of the traveling wave cable; constructing a time-frequency domain joint reflection model; collecting a reflected signal of the traveling wave cable through the signal receiving device to obtain time domain data and frequency domain data of the reflected signal; carrying out conjoint analysis on the time domain data and the frequency domain data by utilizing a time-frequency domain joint reflection model, and extracting characteristic parameters of a reflected signal; calculating impedance change and signal propagation characteristics along the traveling wave cable based on the characteristic parameters in combination with a time-frequency domain joint reflection model; through analysis of impedance change and signal propagation characteristics, intrusion detection, leakage positioning and fault diagnosis along the traveling wave cable are realized.

The invention discloses a power cable fault diagnosis and analysis method and system based on multi-source data, and relates to the technical field of diagnosis and analys.During operation of the system, various sensors are installed in a cable and the surrounding environment of the cable, operation data of the power cable are collected in real time, and after the collected multi-source data are preprocessed, the power cable fault diagnosis and analysis method and system based on the multi-source data are obtained. The method comprises the following steps: calculating key diagnosis parameters by using a machine learning algorithm, obtaining a comprehensive fault diagnosis index CDI, comparing the comprehensive fault diagnosis index CDI with a preset first threshold M and a preset second threshold N, obtaining a fault level and outputting a corresponding processing strategy, and carrying out fault point positioning by using a reflected wave method in combination with multi-source data according to fault characteristics and a cable model. And outputting a specific position of a fault point, accurately positioning the fault point in the cable, integrating analysis results of the modules, and automatically generating a cable fault diagnosis report which comprises a fault type, a fault point position, potential risk analysis and maintenance suggestions.

The invention provides a power line fault distance measurement system and method, and belongs to the technical field of power line detection. The system comprises monitoring terminals deployed at two ends of a line and a background processing system, and each monitoring terminal comprises a sensor module used for detecting a traveling wave current signal related to a power line fault in the line; the data acquisition module is used for extracting the arrival time of a traveling wave head according to the detected traveling wave current signal; the GPS time synchronization module is used for adjusting the local clock of the data acquisition module, reducing the time synchronization error of the two monitoring terminals and correcting the arrival time of the traveling wave head; and the background processing system is used for calculating a traveling wave time difference and a junction wave velocity normalization processing result according to the corrected arrival time at the two ends of the line, and determining a fault position coordinate and a fault type. According to the invention, collaborative optimization of fault positioning precision and type identification in a hybrid power line environment is realized.

The invention relates to the technical field of fault monitoring, in particular to a power transmission line fault monitoring and positioning method, system and device and a medium. The method comprises the following steps: firstly, performing digital conversion on an original current signal to obtain time sequence data, and then identifying and classifying fault events through threshold detection and a feature extraction algorithm to obtain classification labels of fault types; then, based on the classification label, establishing a traveling wave propagation model and carrying out time difference calculation, carrying out clustering analysis on a plurality of wave head data in a preset time window, and judging whether the fault is a single-point fault or a multi-point fault through a clustering result; and finally, a positioning result is transmitted to the central server for comprehensive verification and alarm management, and a final fault response is formed. By introducing a time series data analysis and clustering judgment mechanism, the fault type can be accurately identified, single-point and multi-point fault conditions can be effectively distinguished, and meanwhile, the reliability of a positioning result is improved through comprehensive verification of the central server.

The invention relates to the technical field of cable testing, and discloses an electric wire and cable defect fault detection method and device, and the method comprises the steps: obtaining the burying trend information of a target cable and the test characteristics of a test item, analyzing and determining the position of a cable detection end point, deploying a corresponding detection instrument according to the position of the detection end point, and carrying out the detection. A plurality of tests including electric pulse reflection test, sheath grounding circulation test, infrared temperature measurement test and the like are carried out by using deployed instruments, multi-item test data of the cable are acquired, comprehensive analysis is carried out on the multi-item test data, defects and faults of the cable are accurately positioned, the accuracy and efficiency of fault positioning are improved, and the system can adapt to a complex cable network environment and is suitable for popularization and application. The method has high flexibility and practicability, and solves the problem that cable defects and faults are difficult to accurately position in the prior art.

The invention discloses a cable fault positioning method and system based on reflected wave decomposition and kurtosis sorting, and aims to solve the problem that a cable fault is difficult to detect under a low impedance change rate. The method comprises the steps of transmitting an incident excitation signal to a cable to obtain a first reflection signal in the cable; an improved VMD algorithm is adopted for decomposition to obtain K IMF components, and the IMF with the maximum kurtosis is selected as a second reflection signal; acquiring a time-frequency distribution curve of the second reflected signal by using short-time Fourier transform and frequency spectrum redistribution technologies; and constructing a two-dimensional energy-time curve by extracting an energy value and time under the frequency of the maximum energy amplitude point, and determining a fault position. The system is composed of an incident excitation module, a decomposition module, an STFT-RSP module and a fault positioning output module, and the positioning method is achieved. According to the method, the limitation of a traditional spread spectrum time domain reflection positioning method in cable fault detection is effectively overcome, and an efficient and accurate instructive technology is provided for cable fault positioning and detection.

The invention discloses a power distribution network three-core cable fault distance measurement analysis method and system, and relates to the technical field of fault distance measurement, and the key points of the technical scheme are that the method comprises the steps: carrying out the empirical mode decomposition of three-phase voltage and current signals; generating a dynamic correction wave velocity based on the cable type, the environment temperature and the soil humidity parameter; determining the first arrival time of the wave head of the initial traveling wave according to the instantaneous frequency abrupt change point of the alpha-mode component, screening the second arrival time of the first reflected wave by using the amplitude gradient of the zero-mode component, and calculating the arrival time difference; and calculating an initial fault distance, and calling the impedance matrix to iteratively correct the initial fault distance. According to the method, the dynamic wave velocity is coupled with multiple factors, the limitation of single parameter correction is broken through, and the problem of transient drift of the wave velocity is solved; and the STFT high-frequency resolution and the wavelet low-frequency stability are fused, and the ridge continuity is optimized in combination with dynamic programming, so that the traveling wave head detection precision can be improved.

The invention discloses an operation state fault monitoring method, system and device for a heavy-load overhead line, and relates to the technical field of electrical fault detection of the heavy-load overhead line. The method comprises the following steps: injecting a high-frequency test signal into a heavy-load overhead line to carry out predefined fault detection so as to obtain a total harmonic distortion rate; performing first harmonic optimization adjustment according to comparative analysis of the total harmonic distortion rate and a threshold value; performing harmonic second optimization adjustment according to the monitoring analysis result of the external load fluctuation of the heavy-load overhead line; and performing harmonic third optimization adjustment according to the monitoring analysis result of the external environment fluctuation of the heavy-load overhead line. According to the invention, through multi-stage distribution adjustment, the effect of improving the dynamic regulation and control accuracy of the high-frequency test signal injection fault monitoring method of the heavy-load overhead line in extreme weather is achieved; the problem of insufficient dynamic regulation and control accuracy of a high-frequency test signal injection fault monitoring method of a heavy-load overhead line in extreme weather exists.

The invention relates to a weak current cable fault positioning method and system, and the method comprises the steps: preliminarily locking a fault region through monitoring the axial stress change in real time, injecting a low-frequency pulse signal in a target section, analyzing the reflection waveform characteristics, and extracting the waveform distortion characteristics in a reflection signal; dynamically adjusting the output impedance based on the amplitude attenuation and time delay relationship, and if the dynamically adjusted output impedance cannot enable the output impedance of the injected low-frequency pulse signal to be synchronous with the impedance change trend of the cable, marking as an impedance mismatch point; after an impedance mismatch point is identified, other interferences are eliminated through multi-band signal attenuation difference analysis, and the position of a fault point is determined; the system is used for implementing the method. According to the method and system, stress monitoring and electric signal detection are combined, the detection range is remarkably shortened, the positioning precision and the detection accuracy are improved, and the method and system are suitable for weak current cable fault diagnosis in a complex environment.

The invention discloses a self-adaptive fault reflection method and device based on adjustable excitation frequency, and belongs to the technical field of cable fault detection and positioning. The method comprises the following steps: injecting an excitation signal which can be adjusted in a range of 1kHz-10MHz through an adjustable impedance matching network; collecting a reflected signal and calculating an SNR (f) curve; optimizing by adopting a particle swarm optimization algorithm and taking maximization of a signal-to-noise ratio as a target, and determining an optimal excitation frequency; and finally, calculating the fault position and type based on the optimal frequency. The particle swarm optimization algorithm is adopted to perform adaptive optimization on the excitation frequency, and the adjustable impedance matching network is combined to form a closed-loop adaptive detection framework of excitation-acquisition-analysis-optimization-re-excitation, so that the excitation frequency can be automatically adjusted according to a real-time detection result, and the detection accuracy is improved. And the fault detection sensitivity, the positioning precision and the energy efficiency are obviously improved.

The invention relates to a power distribution network cable fault wave head identification and positioning method and system based on sheath traveling waves, and belongs to the field of power system relay protection. According to the invention, cable fault condition identification is carried out by adopting a sheath traveling wave analysis method. The method comprises the following steps: carrying out identification and fault positioning on a power distribution network cable fault wave head by combining time-frequency analysis with high-pass filtering based on traveling wave time-frequency characteristics of a cable sheath. Firstly, traveling wave measuring points are set at the head end and the tail end of a cable sheath, transient information of the head end and the tail end of the sheath during cable operation is recorded in real time, zero-sequence voltage is set as a fault judgment quantity during cable fault, high-frequency transient quantity information of the cable fault is extracted for high-pass filtering, namely interference variables such as noise and harmonic waves in traveling waves are removed, and the fault judgment quantity is calculated. For the traveling wave signal after filtering processing, each wave head information of the fault traveling wave is calibrated by adopting time-frequency analysis, fault positioning is performed through position information of a fault initial wave head and each catadioptric wave head, a criterion is formed for cable fault positioning, the criterion is simple and reliable, the coupling degree with an actual line is relatively good, and the selectivity and the sensitivity are relatively high.

The invention discloses a power grid fault positioning system and method based on traveling wave distance measurement, relates to the technical field of fault analysis, and solves the technical problems that traveling wave feature analysis, temperature compensation and high-precision synchronization technologies are not effectively integrated, and rapid and accurate fault positioning of a smart power grid is difficult to meet. Through the technical combination of dynamic temperature compensation, high-precision time synchronization and intelligent fault classification, the bottlenecks of traditional traveling wave distance measurement in the aspects of precision, reliability and intelligence are systematically solved, temperature sensors are deployed at key nodes of a cable, the temperature is monitored in real time, the wave speed is dynamically corrected through a formula, the overall error is reduced, and the fault location accuracy is improved. Meanwhile, an optical fiber two-way time transmission method is combined, transmission delay errors are reduced, synchronization reliability is improved, finally, a mapping library is constructed through laboratory simulation and field data, a Euclidean distance matching algorithm is combined, fault reasons are automatically recognized, and rapid positioning of the faults and accurate recognition of the fault reasons are achieved.

The invention relates to the technical field of power distribution network fault positioning, and provides a power distribution network multi-branch line fault positioning method and system based on time domain difference. The power distribution network multi-branch line fault positioning method based on time domain difference comprises the steps of obtaining a fault traveling wave line mode component based on fault traveling wave data, and performing discretization; performing time domain difference operation on the discretized fault voltage traveling wave line mode component, eliminating a sine component, and obtaining a fault traveling wave line mode component signal; constructing an objective function, optimizing a fault traveling wave line mode component signal, and determining a time domain position of a fault traveling wave head to calibrate arrival time of the fault traveling wave head; and if the fault is the trunk line fault, establishing a first fault point reflection wave time sequence constraint based on the basic parameters and the fault section of the fault line in combination with the fault traveling wave head arrival time, and determining the fault point reflection wave head arrival time so as to determine the position of the fault point. The calculation speed and reliability of fault positioning are improved, and the cost is reduced.

The invention discloses a power cable tiny defect positioning method based on a CFI-Z algorithm, and the method comprises the steps: obtaining a reflection coefficient vector of a head end of a power cable obtained through sweep frequency signals based on multiple frequencies, and obtaining a minimum norm least square solution and a closed solution of a power cable fault positioning factor according to a continuous frequency-increasing Z transformation matrix; and obtaining the sparse intensity of the minimum norm least square solution and the closed solution to obtain the final solution of the power cable fault positioning factor, and finally obtaining the position of the power cable defect according to the head end reflection time domain sequence of the power cable to complete the positioning of the early defect of the cable. According to the invention, the problems of insufficient high-frequency components and bandwidth limitation in the injected pulse are solved, so that the defect positioning sensitivity of the power cable is high, the anti-noise capability is strong, the positioning error is small especially under the condition of a long cable or a cable with small defects, and the method has a good effect in early-stage small defect positioning.

The invention relates to the technical field of power monitoring, in particular to an operation state monitoring operation and maintenance method and system for a power cable, and the method comprises the following steps: transmitting a test signal with preset frequency and intensity to a target cable; capturing a test signal transmitted through the cable at the other end of the cable, and predicting the aging degree of the cable through an attenuation index; analyzing the time delay and intensity of a reflected signal in the cable by using a TDR technology, and determining the initial position of potential damage or discontinuity in the cable; performing a multi-frequency signal test on the cable, and analyzing the transmission characteristics of the cable to each frequency signal so as to obtain a fault type; and comprehensively analyzing by using a multi-task learning model to determine the aging condition and the specific damage position of the cable. According to the invention, obvious external damage of the cable can be detected, tiny damage or aging phenomena, invisible to naked eyes, in the cable can be identified, and the requirement of manual operation is reduced, so that the detection efficiency and reliability are improved.

The invention discloses a power distribution network fault positioning method and device based on a satellite time service inverter, and belongs to the technical field of power system fault diagnosis, and the method comprises the steps: obtaining a time service signal of a satellite navigation system, decoding the time service signal to generate a unified space-time reference, distributing the unified space-time reference to a plurality of inverter nodes in a power distribution network, and forming a cooperative measurement network; a coding sequence current signal is injected into a power distribution network line through a master control inverter node; synchronously acquiring response voltage traveling wave data by each inverter node, performing cross-correlation analysis on the response voltage traveling wave data and the coded sequence current signal, and extracting propagation time delay of each inverter node; and correcting the reference line wave velocity by using the current line parameters and the current meteorological data, and calculating fault point position data in combination with propagation time delay. According to the method, an inverter cooperative measurement network is constructed by using satellite time service, a coding sequence current signal is actively injected, and a real-time wave velocity is corrected by combining an intelligent model, so that rapid, accurate and high-reliability positioning of a power distribution network fault can be realized.

The invention belongs to the technical field of power cable fault positioning. The invention discloses a TDR power cable global fault positioning method based on multi-frequency cooperative excitation and environment adaptive correction. The method comprises the following steps: 1) multi-frequency pulse cooperative injection and signal acquisition; 2) environment parameter dynamic sensing and speed correction: embedding a miniature temperature and humidity sensor and a cable insulation state monitoring unit along the cable at an interval of 500m, and collecting laying environment temperature, humidity and insulation material dielectric constant change data in real time; constructing a dynamic speed correction formula based on a preset environment-dielectric constant correlation model; according to the method, the complex fault positioning precision is improved, the environment and scene adaptability is enhanced, and the troubleshooting efficiency is optimized.

The provided are a line fault detection method, system, equipment, and a computer-readable storage medium. The line fault detection method comprises the following steps: Inject a pulse signal into the grounding electrode line and acquire fault voltage traveling wave data responding to the fault point in the grounding electrode line based on the measuring spot; Based on the fault voltage traveling wave data and a preset step size, determine the voltage forward traveling wave sequence and voltage reverse traveling wave sequence for the entire grounding electrode line; Based on the corresponding energy superposition expressions of the voltage forward traveling wave sequence and the voltage reverse traveling wave sequence, determine the integral value sequence of the traveling wave product within a preset time period; Based on the maximum mutation point in the integral value sequence, determine the fault distance.

The invention discloses a wind driven generator blade lightning conductor broken line point positioning method based on a radio frequency transformer, and relates to the field of wind driven generator blade lightning conductor broken line point positioning. A to-be-detected line is connected in series with the radio frequency transformer before being injected into traveling waves, and the change of traveling wave current is converted into the change of transformer output voltage; therefore, the output voltage of the radio frequency transformer is detected to judge the arrival time difference of the incident wave and the reflected wave, and then the breakpoint position is judged by multiplying the wave velocity by the time difference and dividing by 2. According to the wind driven generator blade lightning conductor breaking point positioning method based on the radio frequency transformer, the position of the lightning conductor breaking point can be efficiently, accurately, conveniently and flexibly detected at low cost, positioning measurement of disconnection of a multi-core wire part can be achieved, the specific positions of the breaking point and an abnormal point of the lightning conductor can be effectively determined, and the working efficiency is improved. After the positions of the broken line point and the abnormal point are determined, specific positions are repaired in a targeted manner, so that the cost for replacing the lightning conductor is saved.

A cable fault detection system includes a frequency-modulated continuous-wave (FMCW) signal generator, an amplifier connected with the FMCW signal generator, an impedance matcher, a lead cable connected with the impedance matcher, a mixer, a first signal distributor, a second signal distributor, a cable dictionary, and a data processer. The first and second signal distributors are connected with the amplifier, the impedance matcher, and the mixer. The data processer is connected with the mixer for performing cable fault detection using the cable dictionary and a signal from the mixer.

Provided is a precise fault location method for a collector line in an onshore wind farm. The method includes sends sending, by a slave unit, a high-voltage pulse signal at the beginning of a collector line to measure a cable length at a fault point of the collector line. A master unit and the slave unit send high-voltage pulse signals to each other to measure a cable length at any point on the collector line, thereby obtaining a geographical location corresponding to the cable length. The two measured cable lengths are compared and if the measured lengths are inconsistent, the master unit is moved, to make the two measured lengths equal with multiple approaches. In this case, the position of the master unit is a geographical location corresponding to the fault point.

An electronic device for integrated monitoring of a wind turbine is described. This electronic device may selectively electrically couple to a lightning-protection system, which is included within a wind-turbine blade or wing. For example, the electronic device may establish the electrical coupling when the wind-turbine blade is orientated below a horizontal direction (such as an orientation having an angle between 180° and 360°). Then, the electronic device may characterize the wind-turbine blade using time-domain reflectometry. More generally, the electronic device may characterize the wind-turbine blade using a wide variety of measurements, such as: pressure, humidity, acoustic, vibration, etc. Moreover, measurement results may be communication from the electronic device to a remote computer (such as a cloud-based computer system) for analysis. When the analysis identifies potential damage to the wind-turbine blade, the remote computer and / or the electronic device may perform a remedial action, such as recommending enhanced inspection and / or a repair.

The invention discloses a power distribution network line fault positioning system based on multi-source information fusion, which relates to the technical field of power system operation and maintenance and comprises a data acquisition module, a data preprocessing module, an electric network topology management module, a fault prediction module, a fault judgment module and a man-machine interaction and alarm module. The method comprises the following steps: acquiring running state information from a power distribution network in real time, generating a structured multi-dimensional information database according to the running state information acquired by a data acquisition module, and performing time alignment, format standardization and feature vector construction on the acquired running state information to generate the structured multi-dimensional information database; according to the method, a fault section is preliminarily judged according to fault features, a fault state prediction model is constructed, a multi-dimensional information database is used for estimating state variables of the model, and the method aims at overcoming the defects that in the prior art, fault positioning fuzziness and reliability are insufficient due to the fact that a single information source is relied on.

The invention discloses a power transmission line fault identification method and device based on artificial intelligence, and relates to the technical field of power transmission line fault identification. Determining line data of the target area, performing data acquisition according to the line data to obtain an original traveling wave signal, and filtering the original traveling wave signal to obtain a time domain signal; performing adaptive variational mode decomposition on the time domain signal to obtain a mode component, and performing calculation according to the mode component to obtain a fault point; and determining an inspection scheme according to the fault point, executing the inspection scheme to obtain a fault point image, and performing alarm judgment on the fault point image through artificial intelligence. Line data and traveling wave signals are accurately collected, noise is filtered by adopting an advanced filtering technology, and the signal quality is improved; adaptive variational mode decomposition is utilized to accurately extract a mode component, and the fault point positioning precision is enhanced; faults are quickly and accurately judged by combining artificial intelligence image recognition, automatic operation and maintenance are realized, and the operation and maintenance efficiency of the power transmission line and the stability of the power system are improved.

The invention relates to the technical field of electromagnetic measurement, and discloses a line partial discharge positioning method and system based on pulse signal analysis, and the method comprises the steps: carrying out the band-pass filtering of pulse signal data, and obtaining a preprocessing signal; constructing a waveform template library based on the historical partial discharge pulse waveform data; screening out a partial discharge pulse and an interference pulse in the preprocessed signal to obtain a pulse matching result of the preprocessed signal; determining time difference data of the preprocessed signal according to time differences of pulses reaching different sensors in the pulse matching result; constructing an initial propagation velocity model according to the parameters and the environment data, performing iterative optimization on the initial propagation velocity model according to the time difference data, and determining an initial position of a partial discharge source in the line; correcting the initial propagation velocity model according to the initial position and the actual propagation path to obtain a target propagation model, and determining position coordinates of a partial discharge source in the target line according to the target propagation model; according to the invention, the accuracy of line partial discharge positioning can be improved.

Method for characterizing the aging of an object comprising an insulating material, the method comprising the steps of: Determining (301), from a measurement on the insulating material, an estimate of the complex permittivity of the insulator as a function of frequency, called the permittivity spectrum; Evaluating (303) whether the permittivity spectrum exhibits a variation in the value of the imaginary permittivity and / or a variation in the value of the real permittivity within a given frequency range, characterizing an aging state of the conduit. Figure 3

The invention discloses a cable defect detection device and method. The detection device comprises a high-frequency current sensor, a signal acquisition module, an algorithm analysis module, a high-frequency pulse detection module and a fault diagnosis module, the high-frequency current sensor is used for detecting a current pulse signal on a cable grounding wire, converting the current pulse signal into a voltage signal and transmitting the voltage signal to the signal acquisition module; the signal acquisition module is used for amplifying, filtering and detecting the voltage signal; the algorithm analysis module is used for carrying out feature extraction and analysis on the processed voltage signals and carrying out feature classification and clustering on the voltage signals; the high-frequency pulse detection module is used for carrying out noise reduction processing on the voltage signal and extracting the voltage signal representing the partial discharge defect of the cable; and the fault diagnosis module is used for determining the type and degree of the cable defect according to the voltage signal representing the partial discharge defect of the cable and historical data. Cable line faults are rapidly judged, and the reliability of a power supply system is improved.