CN-122017476-A - Fault location method and system based on breaker traveling wave signals

CN122017476ACN 122017476 ACN122017476 ACN 122017476ACN-122017476-A

Abstract

The invention provides a fault location method and a fault location system based on a breaker traveling wave signal, and relates to the technical field of power grid fault detection, wherein the method comprises the following steps of constructing a line topology library comprising tower coordinates and wire sag; the method comprises the steps of collecting transient traveling wave signals generated during opening or closing operation of a circuit breaker, determining an arrival time set of traveling wave heads, resolving geographic coordinates of fault points and tower sections to which the fault points belong, and calculating electrical distances of the fault points along a line relative to a preset reference point according to the resolved geographic coordinates of the fault points and the tower sections to which the fault points belong to obtain a final fault distance measurement result. The invention utilizes the equivalent distance between the initial wave and the reflected wave to eliminate clock synchronization errors, combines least square solution and coordinate projection to map the electrical measurement value into the geographic coordinates of a specific tower section, can shorten the fault finding time from an hour level to a minute level, and greatly improves the power supply reliability.

Inventors

TAN ZHANWEN
BI JUAN
ZHANG SHAOLEI
HU CHANGXU
TANG SHIXUAN
HUANG SHUO

Assignees

安徽海图智能科技有限公司

Dates

Publication Date: 20260512
Application Date: 20260416

Claims (9)

1. The fault location method based on the breaker traveling wave signal is characterized by comprising the following steps of: s1, collecting point cloud data of a circuit breaker line, and generating a line point cloud model through three-dimensional reconstruction; S2, acquiring transient traveling wave signals generated during opening or closing operation of the circuit breaker based on a mutual inductor pre-installed on the circuit breaker; S3, filtering and denoising the transient traveling wave signals, performing wavelet transformation on the preprocessed transient traveling wave signals to obtain a two-dimensional time-frequency spectrogram, constructing a weight function matrix by using the two-dimensional time-frequency spectrogram, determining the movement speed and direction of each energy point by calculating an optimized direction field of the energy point to form energy flow distribution, calculating the directional entropy and amplitude entropy of energy flow vectors in each window according to the energy flow distribution and along a sliding analysis window of a time axis, constructing a traveling wave confusion index by combining the average movement speed of the energy points in the windows, and determining the arrival time of a candidate traveling wave surge by combining a preset confusion threshold; s4, determining a propagation path and a reflection point of the fault traveling wave by utilizing a two-way ranging time difference positioning algorithm according to the arrival time set of the traveling wave head, and solving the geographic coordinates of the fault point and a tower section to which the fault point belongs by combining a line topology library; and S5, calculating the electrical distance between the fault point and a preset reference point along the line according to the calculated geographical coordinates of the fault point and the tower section to which the fault point belongs, and obtaining a final fault distance measurement result.
2. The fault location method based on breaker traveling wave signals according to claim 1, wherein the constructing a weight function matrix using a two-dimensional time-frequency spectrogram, and determining the movement speed and direction of each energy point by calculating an optimized direction field of the energy point, so as to form an energy flow distribution comprises the following steps: S321, constructing a composite weight function matrix fusing amplitude intensity and frequency change rate based on energy amplitude of each pixel point in a two-dimensional time-frequency spectrogram and distribution gradient of each pixel point on a frequency axis; s322, calculating an initial direction field of the energy flow based on the composite weight function matrix and by combining a covariance manifold method; S323, carrying out iterative smoothing and correction on an initial direction field of the energy flow by utilizing propagation speed range constraint and frequency attenuation priori of the transient traveling wave signal on a time-frequency plane to obtain an optimized direction field of the energy point; S324, according to the optimized direction field of the energy points, the movement speed of each energy point is estimated by calculating the change rate of the energy amplitude along the direction field, and the movement speed and the optimized direction field are combined to obtain the movement speed and the direction of each energy point so as to form energy flow distribution.
3. The fault location method based on the traveling wave signal of the circuit breaker according to claim 2, wherein the calculating the initial direction field of the energy flow based on the composite weight function matrix in combination with the covariance manifold method comprises the following steps: S3221, taking a composite weight function matrix as a two-dimensional image, and dividing the two-dimensional image into a plurality of mutually overlapped rectangular areas, wherein for each rectangular area, a feature vector set is formed by extracting multi-dimensional features of each pixel point in the rectangular area; S3222, calculating covariance matrixes of all feature vectors in the rectangular area based on the feature vector set of each rectangular area to obtain covariance descriptors of the rectangular area; S3223, carrying out iterative solution on covariance descriptors of all rectangular areas to obtain Karcher mean points serving as reference standard; s3224, projecting covariance descriptors of each rectangular area to a tangent space at a Karcher mean point by using a logarithmic mapping mode to obtain vectors in the tangent space; S3225, for each rectangular region, extracting components corresponding to the frequency gradient characteristics and the time gradient characteristics from the tangent space vectors, and constructing a local gradient covariance matrix of the rectangular region; S3226, performing smoothing on the initial energy flow directions of all the region center points to obtain an initial energy flow direction field.
4. The fault location method based on breaker traveling wave signals according to claim 3, wherein the iterative smoothing and correction are performed on the initial direction field of the energy flow by using the propagation speed range constraint and the frequency attenuation priori of the transient traveling wave signals on the time-frequency plane, and the optimized direction field of the energy point is obtained, which comprises the following steps: S3231, determining propagation characteristics of transient traveling wave signals in a circuit based on the type of the circuit breaker, determining propagation speed range constraint and frequency attenuation priori of the transient traveling wave signals on a time-frequency plane, and constructing a direction field optimization energy functional according to the propagation speed range constraint and the frequency attenuation priori; S3232, carrying out iterative solution on the direction field optimization energy functional, and smoothing and correcting an initial direction field of the energy flow in each iteration; and S3233, stopping iteration when the change quantity of the direction field of two adjacent iterations is smaller than a preset convergence threshold or reaches a preset maximum iteration number, and obtaining the optimized direction field of each energy point.
5. The fault location method based on the traveling wave signal of the circuit breaker according to claim 4, wherein the error analysis is performed on the arrival time of the candidate traveling wave surge by using three-phase different opening and closing periodic parameters of the circuit breaker and the contact closing bounce time as prior constraints, and the final arrival time set of the traveling wave head is obtained through screening and interpolation processing, and the method comprises the following steps: S341, arranging the arrival time of the candidate traveling wave surge according to the time sequence, and calculating the time difference between every two phases of time, if the time difference of any two phases is beyond the allowable range of the three-phase switching-on/off different periodic parameters of the breaker, judging the arrival time as abnormal data, and deleting the abnormal data to obtain the candidate time after preliminary screening; S342, taking each candidate moment after preliminary screening as a starting point, and expanding the duration corresponding to the contact closing bounce time parameter forwards and backwards to serve as a refusal action time window; if a plurality of candidate moments occur in the same refusing time window, the moment with the maximum energy amplitude is reserved as an effective wave head, and the rest wave heads which are judged to be pseudo wave heads generated by mechanical bounce are removed, so that the wave head moment after secondary screening is obtained; S343, calculating the electrical distance corresponding to the time difference between adjacent wave heads based on the tower coordinates and the line length parameters in the line topology library, judging that reflected waves or refracted waves are reserved if the electrical distance has an integer multiple relation with the line length or the tower distance, and eliminating the reflected waves or refracted waves as noise interference to obtain the wave heads after three times of screening; And S344, extracting original waveform fragments with the preset lengths before and after each wave head moment after three times of screening, performing local fitting by adopting a spline interpolation method, taking the position with the maximum energy change rate as the final wave head arrival moment, and outputting a complete wave head arrival time set.
6. The fault location method based on the breaker traveling wave signal according to claim 1, wherein the determining the propagation path and the reflection point of the fault traveling wave according to the arrival time set of the traveling wave head by using a two-way ranging time difference positioning algorithm, and combining the line topology library, and resolving the geographic coordinates of the fault point and the tower section to which the fault point belongs comprises the following steps: s41, respectively extracting an initial traveling wave surge arrival time and a fault point reflected wave time according to a traveling wave head arrival time set, and determining the wave speed of a transient traveling wave signal by combining a line topology library; s42, calculating an equivalent distance between the circuit breaker and the fault point based on the initial traveling wave surge arrival time, the fault point reflected wave time and the wave speed of the transient traveling wave signal; s43, taking a circuit breaker which receives the traveling wave surge first as a reference station, and establishing a linear equation of a fault point coordinate by combining the position information of the circuit breaker; s44, solving a linear equation between the coordinates of the fault point and the reference distance to obtain the preliminary geographic coordinates of the fault point, and determining the geographic coordinates of the fault point and the tower section to which the fault point belongs by combining a line topology library.
7. The fault location method based on breaker traveling wave signals according to claim 6, wherein the determining the wave speed of the transient traveling wave signals in combination with the line topology base comprises the steps of: extracting all intact line section information with known length and no faults from a line topology library, and extracting traveling wave head arrival time generated by last operation of circuit breakers at two ends of each line section before faults from traveling wave head arrival time set; Calculating the length of the line sections in the line topology library to obtain a dynamic wave speed candidate value in the current environment; And carrying out consistency test on the dynamic wave velocity candidate values obtained by calculating the plurality of intact line sections, removing the deviation abnormal values, and then taking a weighted average value to obtain the final dynamic wave velocity of the transient traveling wave signal of the current line.
8. The fault location method based on the traveling wave signal of the circuit breaker according to claim 6, wherein the step of using the circuit breaker that receives the traveling wave surge first as a reference station and combining the position information of the circuit breaker to establish a linear equation of the coordinates of the fault point comprises the steps of: s431, determining a breaker which receives the traveling wave surge first as a reference station according to the arrival time set and the equivalent distance of the traveling wave head; S432, extracting coordinates from a line topology library for each other breaker, and calculating a reference station distance difference by combining the equivalent distance of the reference station; s433, based on the arrival time difference positioning principle, the quadratic term is eliminated by utilizing a square subtraction method, and a linear equation about the coordinates of the fault points is established by combining the coordinates of each breaker and the distance difference of the reference station.
9. A fault location system based on a breaker traveling wave signal for implementing the fault location method based on a breaker traveling wave signal according to any one of claims 1 to 8, the system comprising: The system comprises a data acquisition module, a line point cloud model, a line topology library, a line processing module and a line processing module, wherein the data acquisition module is used for collecting point cloud data of a circuit breaker and generating a circuit point cloud model through three-dimensional reconstruction; The signal acquisition module is used for acquiring transient traveling wave signals generated during opening or closing operation of the circuit breakers based on a mutual inductor which is pre-installed on the circuit breakers, and recording the arrival time of the transient traveling wave signals of each circuit breaker; The time analysis module is used for carrying out filtering and denoising pretreatment on the transient traveling wave signals and carrying out wavelet transformation treatment on the pretreated transient traveling wave signals to obtain a two-dimensional time-frequency spectrogram; the method comprises the steps of constructing a weight function matrix by utilizing a two-dimensional time-frequency spectrogram, determining the movement speed and direction of each energy point by calculating the optimized direction field of the energy point to form energy flow distribution, calculating the directional entropy and the amplitude entropy of energy flow vectors in each window according to the energy flow distribution and a sliding analysis window along a time axis, constructing a traveling wave confusion index by combining the average movement speed of the energy points in the window, and determining candidate traveling wave surge arrival time by combining a preset confusion threshold; The coordinate resolving module is used for determining the propagation path and the reflection point of the fault traveling wave by utilizing a time difference positioning algorithm of two-way ranging according to the arrival time set of the traveling wave head, and resolving the geographic coordinates of the fault point and the tower section to which the fault point belongs by combining a line topology library; The distance measurement result calculation module is used for calculating the electrical distance between the fault point and a preset reference point along the line according to the calculated geographical coordinates of the fault point and the tower section to which the fault point belongs, and obtaining a final fault distance measurement result.

Description

Fault location method and system based on breaker traveling wave signals Technical Field The invention relates to the technical field of power grid fault detection, in particular to a fault location method and system based on a breaker traveling wave signal. Background The distribution network is taken as a main component of a power system in China, bears important tasks of conveying and distributing electric energy, is a network closely contacted with users in a power transmission link, and is closely related to the safe and stable operation of the normal operation and development of various industries in China. Therefore, rapid fault detection and troubleshooting of the power distribution network is particularly important. The short circuit fault condition of the distribution network is mostly single-phase earth fault, but in actual engineering, the distribution network has complex operation, tree line and foreign matter hidden trouble and other factors due to the complex structure of feeder line branch multiple networks, so that the operation environment is complex. At present, fault location technology based on traveling wave principle receives extensive attention because of advantages such as its positioning accuracy is high, response speed is fast. However, the conventional traveling wave distance measuring method still has the following technical problems in practical application that the conventional traveling wave distance measuring method generally adopts fixed theoretical wave speed to perform distance calculation, but the actual traveling wave speed is influenced by various factors such as line type, wire sag, environment temperature, load current and the like, dynamic change characteristics are presented, and a large error exists in a distance measuring result due to fixed wave speed assumption. Meanwhile, in an actual complex power grid environment, a traveling wave signal is often mixed with a power frequency component, high-frequency noise and mechanical vibration interference generated by breaker operation, the arrival time of a traveling wave surge is difficult to accurately extract from a strong noise background by a traditional method, and wave head missing detection or false detection is easy to occur. Especially when faults occur near the zero crossing of the voltage, the traveling wave signal energy is weaker, and wave head identification is more difficult. For the problems in the related art, no effective solution has been proposed at present. Disclosure of Invention In view of the above, the present invention provides a fault location method and system based on a traveling wave signal of a circuit breaker, so as to solve the above-mentioned problems. In order to solve the problems, the invention adopts the following specific technical scheme: According to one aspect of the invention, a fault location method based on a breaker traveling wave signal is provided, comprising the following steps: s1, collecting point cloud data of a circuit breaker line, and generating a line point cloud model through three-dimensional reconstruction; S2, acquiring transient traveling wave signals generated during opening or closing operation of the circuit breaker based on a mutual inductor pre-installed on the circuit breaker; S3, preprocessing a transient traveling wave signal, determining the arrival time of a traveling wave surge according to the preprocessed transient traveling wave signal, and carrying out error analysis on the arrival time of the traveling wave surge by combining three-phase different opening and closing periodic parameters of a breaker and the contact closing bounce time based on the energy flow direction to determine a traveling wave head arrival time set; s4, determining a propagation path and a reflection point of the fault traveling wave by utilizing a two-way ranging time difference positioning algorithm according to the arrival time set of the traveling wave head, and solving the geographic coordinates of the fault point and a tower section to which the fault point belongs by combining a line topology library; and S5, calculating the electrical distance between the fault point and a preset reference point along the line according to the calculated geographical coordinates of the fault point and the tower section to which the fault point belongs, and obtaining a final fault distance measurement result. Preferably, the method comprises the steps of preprocessing transient traveling wave signals, determining the arrival time of traveling wave surge according to the preprocessed transient traveling wave signals, carrying out error analysis on the arrival time of traveling wave surge based on the energy flow direction and combining three-phase different opening and closing periodic parameters of a breaker and contact closing bounce time, and determining a traveling wave head arrival time set, wherein the steps comprise the following steps: S31, performing filtering and denoisin