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CN-121978456-A - Power transmission line fault location method and device based on bimodal traveling wave fusion

CN121978456ACN 121978456 ACN121978456 ACN 121978456ACN-121978456-A

Abstract

The invention relates to a power transmission line fault location technology of a power system, and discloses a power transmission line fault location method and device based on bimodal traveling wave fusion. According to the method, current and voltage signals are collected through multiple channels, high-frequency components are extracted through time synchronization and wavelet decomposition, wave head candidates are identified through mode maximum detection and morphological processing, and real wave heads are confirmed through combination of dynamic threshold values and multiple channels. Calculating a fault distance through the double-end wave head time stamp, correcting according to wave speed, improving distance measurement accuracy, mapping the fault position into longitude and latitude coordinates, overlapping GIS data to mark fault points and nearest towers, generating a navigation file supporting offline positioning, and pushing the navigation file to emergency repair personnel through a notification module. The invention realizes high precision, strong robustness and visualization of fault location, improves adaptability and rush repair efficiency of fault distance measurement, and has good engineering application value.

Inventors

  • ZHANG XINHONG
  • SUN ZHIYIN
  • ZHANG LONGBIAO
  • SHI GUOZHONG
  • ZHANG QISHUN
  • ZHAO JIAQI

Assignees

  • 中宝电气有限公司

Dates

Publication Date
20260505
Application Date
20260121

Claims (10)

  1. 1. A power transmission line fault location method based on bimodal traveling wave fusion is characterized by comprising the following steps: s1, acquiring multiple paths of current signals and multiple paths of voltage signals of a power transmission line through a broadband transformer group, preprocessing the current signals and the multiple paths of voltage signals through a band-pass filter and a differential circuit, and converting the current signals and the voltage signals into digital signals through a multi-channel analog-to-digital conversion module and temporarily storing the digital signals; S2, receiving a second pulse signal by utilizing a high-precision time synchronization technology, acquiring a nanosecond time stamp, calibrating digital signals of all channels, eliminating phase differences, and outputting time-aligned multichannel signals; s3, respectively carrying out wavelet decomposition on the multichannel signals to extract high-frequency components, preliminarily screening out wave head candidate points by using a mode maximum detection algorithm, and carrying out morphological expansion and corrosion treatment on the wave head candidate points to obtain a purified wave head candidate set; S4, setting an initial threshold, screening the wave head candidate set based on the initial threshold, dynamically adjusting the initial threshold according to the real-time noise level and the candidate point density for the wave head candidate points which do not pass through the initial threshold, screening again, and further confirming the final real wave head according to a multichannel association rule and a zero sequence wave head priority principle for all the wave head candidate points which pass through the screening; S5, exchanging time stamps of the local real wave heads and the real wave heads of the opposite ends, and calculating the fault distance from the fault point to the local device according to a wave speed correction formula; s6, mapping the fault point into longitude and latitude coordinates by adopting a linear interpolation formula, and generating a visual label by combining line GIS data; and S7, generating a navigation file supporting offline use based on longitude and latitude coordinates of the fault point and real-time traffic information, and pushing a path and a fault abstract to a rush-repair person in a short message or mail mode through an automatic notification module.
  2. 2. The method according to claim 1, wherein in the step 2, the analysis and correction of the time residual error are performed on any two-channel signals by using a cross-correlation algorithm, and specifically includes: Extracting any two channel signals, and calculating the correlation degree of any two channel signals under different offset by a sliding delay mode according to the consistency of the amplitude variation trend and the time sequence of the signals to obtain a complete cross-correlation curve; Identifying the time offset corresponding to the peak value position in the cross-correlation curve, comparing the time offset with a synchronization tolerance threshold, and marking that any two channel signals are synchronized if the time offset is smaller than the synchronization tolerance threshold; and for the channel pairs exceeding the synchronization tolerance threshold, performing fine adjustment compensation on the time stamp labels of the channel signals, and shifting the whole signals forward or backward according to the time axis until the time residual among all channels is smaller than or equal to the synchronization tolerance threshold.
  3. 3. The method of claim 1, wherein in the step 3, db4 wavelet-based processing current signals and db6 wavelet-based processing voltage signals are adopted, the number of decomposition layers is three, wherein the first layer of decomposition retains high-frequency narrowband impact characteristics, the second layer corresponds to harmonic response of a middle frequency region, the third layer reflects waveform gradual change of a low frequency region, and each layer of wavelet coefficients establishes a mapping relation with channel identifiers according to time sequence to form high-frequency characteristic sequences of current and voltage under different scales.
  4. 4. The method according to claim 3, wherein in the step 3, a mode maximum detection algorithm scans the high frequency component sequence according to the amplitude variation trend, identifies local extremum points formed by amplitude sudden increase or sudden decrease of adjacent sampling points, and records the time position, wavelet coefficient amplitude and channel number corresponding to the local extremum points to form a preliminary wave head candidate set.
  5. 5. The method according to claim 1, wherein a parameter model is constructed in advance based on different voltage levels, line lengths and historical fault signal libraries to form dynamic correspondence rules between main frequency and structural element sizes, frequency bandwidths and length thresholds, in the step 3, the high-frequency components are subjected to spectrum analysis to obtain characteristic parameters of signals in a target frequency band, the characteristic parameters comprise frequency main components, frequency bandwidths, power spectral densities and frequency energy distribution, bandwidth ranges and noise energy duty ratios in main frequency and frequency domain energy concentrations of the signals are calculated based on the characteristic parameters, and a mapping relation between signal spectrum characteristics and morphological parameters is established; Acquiring a specific structural element size and a specific length threshold based on the parameter model and the mapping relation; The expanding operation aggregates the wave head candidate points adjacent in time based on the specific structural element size, and the erosion operation performs deletion processing on the wave head candidate points which are isolated and have the time span smaller than the specific length threshold.
  6. 6. The method according to claim 1, wherein in the step 4, the initial threshold is Wherein T init is the initial threshold, And Respectively obtaining the average value and standard deviation of the amplitude values of the historical wave heads, wherein k is an adjustable coefficient, and the adjustable coefficient is configured based on the signal-to-noise environments and the historical statistical characteristics of different power transmission lines; the dynamic adjustment formula of the initial threshold value is as follows: wherein T adj is a dynamically adjusted threshold, And And (3) as a parameter adjustment coefficient, N is the real-time noise level, and D is the candidate point density.
  7. 7. The method according to claim 1, wherein in the step 5, the wave speed correction formula dynamically adjusts the reference wave speed based on line parameters and environmental conditions, and obtains the wave speed correction value, wherein the line parameters include a line type, a sectional area, a laying mode, an insulation level, and a grounding mode, and the environmental conditions include a real-time air temperature, an atmospheric pressure, and a humidity along the line.
  8. 8. The method according to claim 1, wherein in the step 6, the longitude and latitude coordinates of the fault point are calculated by using a linear interpolation formula based on the fault distance and the line GIS data, wherein the line GIS data includes the start point and the end point of the power transmission line and longitude and latitude coordinate information of all towers; And calculating the space distance between the fault point and the nearest tower, and carrying out map marking on the fault position based on the longitude and latitude coordinates of the fault point, the nearest tower and the space distance.
  9. 9. The method according to claim 1, wherein in the step 7, a repair planning path is generated based on the longitude and latitude coordinates of the fault point and the real-time traffic information, and the longitude and latitude coordinates of the fault point and the repair path planning result are spatially encoded by combining the road number, the steering node and the distance parameter corresponding to the repair planning path in the GIS map, so as to form the navigation file which does not depend on absolute coordinates and is based on relative path information, wherein the navigation file format complies with OpenLR or equivalent standard, and supports offline positioning in a network-free state.
  10. 10. A power transmission line fault distance measuring device based on the method of any one of claims 1 to 9, comprising a signal acquisition module, a time synchronization module, a feature extraction module, a wave head fusion module, a fault calculation module, a geographic information module and a path planning module corresponding to each step of the method; The signal acquisition module is used for acquiring multiple paths of current signals and multiple paths of voltage signals of the power transmission line through the broadband transformer group, and converting the current signals and the voltage signals into digital signals through the multichannel analog-to-digital conversion module and temporarily storing the digital signals after the current signals and the voltage signals are subjected to band-pass filtering and preprocessing by the differential circuit; The time synchronization module is used for receiving the second pulse signal by utilizing a high-precision time synchronization technology, acquiring nanosecond time stamps, calibrating the digital signals of each channel, eliminating phase differences and outputting time-aligned multichannel signals; the characteristic extraction module is used for respectively carrying out wavelet decomposition on the multichannel signals to extract high-frequency components, preliminarily screening out wave head candidate points by applying a mode maximum detection algorithm, and carrying out morphological expansion and corrosion treatment on the wave head candidate points to obtain a purified wave head candidate set; The wave head fusion module is used for screening the wave head candidate set based on the initial threshold value, dynamically adjusting the initial threshold value according to the real-time noise level and the candidate point density, screening again, and further confirming the final real wave head according to the multichannel association rule and the zero sequence wave head priority principle for all the wave head candidate points which pass through the screening; The fault calculation module is used for setting an initial threshold value, exchanging time stamps of local real wave heads and real wave heads of opposite ends, and calculating the fault distance from a fault point to a local device according to a wave speed correction formula; The geographic information module is used for mapping the fault point into longitude and latitude coordinates by adopting a linear interpolation formula and generating a visual label by combining line GIS data; the path planning module is used for generating a navigation file supporting offline use according to longitude and latitude coordinates of the fault point and real-time traffic information, and pushing a path and a fault abstract to a rush-repair person in a short message or mail mode through the automatic notification module.

Description

Power transmission line fault location method and device based on bimodal traveling wave fusion Technical Field The invention relates to the technical field of power system monitoring and diagnosis, in particular to a power transmission line fault location method and device based on bimodal traveling wave fusion. Background The fault location technology of the power transmission line is a key link in the operation and maintenance of the power system, and aims to quickly and accurately locate fault points so as to shorten fault maintenance time and improve power supply reliability. Along with the continuous expansion of the power grid scale and the improvement of the reliability requirement, the traditional fault location method is subjected to the following main development stages, namely, the first stage of the impedance-based fault location method is that an early fault location commonly adopts a current and voltage impedance method, and the impedance value between a fault point and a measuring end is calculated by measuring the current and voltage changes during fault and combining the line characteristic parameters and is converted into the distance. However, the method has great dependence on the accuracy of line parameters, and the positioning accuracy is difficult to ensure when the topology of the power grid is complex or the parameters are uncertain. In the second stage, time difference method and frequency domain method based on waveform identification, with the development of digital technology, methods of Time-of-Arrival (Time-of-Arrival) and frequency domain analysis (Fourier/wavelet transformation) using fault current or voltage waveform characteristics are presented. The method realizes faster ranging speed by extracting the traveling wave head or the high-frequency component in the fault signal, but only depends on a single path or a single mode signal, is easily influenced by noise and multipath interference, and has higher false detection and omission ratio. In the third stage, in order to overcome the limitation of the single-mode method, a multichannel current and voltage signal fusion technology is introduced in recent years. By collecting multiple paths of signals in parallel and carrying out joint extraction and correlation analysis on current and voltage traveling wave characteristics, the reliability and positioning accuracy of wave head detection can be remarkably improved. Meanwhile, the introduction of algorithms such as dynamic threshold adjustment, cross-correlation synchronous verification and the like provides technical support for robustness under complex working conditions. However, the existing multi-mode traveling wave fusion method still has the defects that the first threshold value is static and single in setting, the noise level and the signal density which are difficult to adapt to the real-time change of the scene are not enough, the second wave head candidate point screening and noise suppression means are easy to produce false detection or omission, the third time synchronization scheme is mainly hardware-level synchronization, software-level cross-correlation verification is lacked, synchronization errors cannot be effectively quantized, and the fourth fault ranging result is lack of connection with the scene visualization and navigation, so that the comprehensive requirements of the scene rush repair cannot be met. Therefore, it is necessary to provide a new power transmission line fault location method and device based on bimodal traveling wave fusion, which comprehensively improves the accuracy, reliability and operability of fault location through wave head extraction, multi-channel dynamic threshold screening and association confirmation, synchronization verification of cross-correlation software verification, geographic information mapping and offline navigation file generation combined with wavelet decomposition and morphological processing. Disclosure of Invention Aiming at the problems that a single-mode signal is easy to be interfered by noise, a threshold value is set to be static, a time synchronization error is difficult to quantify, a ranging result is difficult to be visualized on site, navigation is disjointed and the like in the conventional power transmission line fault ranging method, the invention provides a power transmission line fault ranging method and device based on bimodal traveling wave fusion. The end-to-end closed loop of on-site rush repair navigation from fault wave head detection is realized through parallel acquisition and fusion extraction of current and voltage traveling wave signals, dynamic threshold screening, multi-channel association confirmation, software cross-correlation synchronous verification, geographic information mapping and off-line navigation file generation. In a first aspect, the present application provides a power transmission line fault location method based on bimodal traveling wave fusion, where the metho