CN-122017472-A - Positioning method, system, electronic equipment and medium for low-voltage cable leakage fault point

CN122017472ACN 122017472 ACN122017472 ACN 122017472ACN-122017472-A

Abstract

The invention relates to the technical field of power system fault detection, in particular to a method, a system, electronic equipment and a medium for positioning a low-voltage cable leakage fault point; the method comprises the steps of responding to a triggering signal of an electric leakage fault, obtaining fault line section information of the electric leakage, injecting a target current signal into a fault cable corresponding to the fault line section information, collecting a magnetic field signal along the path direction of the fault cable by using a non-contact sensor after the target current signal is injected into the fault cable, converting the magnetic field signal into an electric signal, and determining the position of the electric leakage fault point of the low-voltage cable according to the signal intensity mutation point of the electric signal. By the mode, the technical problem that the existing leakage fault positioning technology has insufficient non-contact measurement precision is solved, and the accuracy, safety and efficiency of fault positioning in complex environments, particularly in the situation of hidden cables are improved.

Inventors

LIU JIANGTAO
CHEN SHANSHAN
XIA YIMING
He Liye
WU ANJIE
QIN FAN
LU HONGYU
YU XIRONG
ZHANG BING

Assignees

国网浙江省电力有限公司龙泉市供电公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The method for positioning the low-voltage cable leakage fault point is characterized by comprising the following steps of: responding to a triggering signal of the leakage fault, and acquiring fault line section information of the leakage; injecting a target current signal into a fault cable corresponding to the fault line section information, wherein the target working frequency of the target current signal is determined based on cable distribution parameters and environment interference parameters through a quantitative calculation model and a dynamic frequency self-adaptive adjustment mechanism; After a target current signal is injected into the fault cable, a non-contact sensor is used for collecting a magnetic field signal along the direction of the path of the fault cable, and the magnetic field signal is converted into an electric signal; and determining the position of the low-voltage cable leakage fault point according to the signal intensity abrupt change point of the electric signal.
2. The method of claim 1, wherein the trigger signal is generated by the residual current monitoring platform when the residual current monitoring platform detects that the residual current value exceeds a preset threshold, and wherein the step of obtaining fault line segment information for the occurrence of the electrical leakage comprises: Acquiring action state information of the multi-stage residual current protector by the multi-stage residual current protector, performing action time sequence analysis on the action state information, and outputting fault line section information with electric leakage; or using a clamp ammeter to measure the current of each distribution branch of the low-voltage cable, executing distribution abnormality analysis according to the measured current value, and outputting the fault line section information.
3. The method of claim 1, wherein prior to injecting a target current signal into the faulty cable corresponding to the faulty line segment information, the method further comprises: acquiring cable distribution parameters of the fault cable and environment interference parameters of a field environment; calculating to obtain a theoretical target working frequency through a quantitative calculation model based on the cable distribution parameter and the environment interference parameter; Performing environment interference correction and frequency band constraint verification on the theoretical target working frequency to obtain an adjusted frequency; And determining the target working frequency of the target current signal through a preset field self-adaptive calibration mechanism based on the adjusted frequency.
4. The method of claim 1, wherein the capturing the magnetic field signal along the path of the faulty cable using the non-contact sensor and converting the magnetic field signal into an electrical signal comprises: inducing the magnetic field signal and outputting induced potential through a composite magnetic core structure, wherein the composite magnetic core structure is formed by materials with different magnetic permeability characteristics so as to realize broadband magnetic field induction; Performing a filtering process on the induced potential to suppress out-of-band interference; performing gain adjustment processing on the filtered signal to adapt the signal amplitude to the input range of the analog-to-digital converter; and performing analog-to-digital conversion processing on the signal subjected to gain adjustment to obtain an electric signal in a digital form.
5. The method of claim 1, wherein determining the location of the low voltage cable leakage fault point based on the signal strength discontinuity of the electrical signal comprises: Performing signal intensity calculation processing on the electric signals to obtain signal intensity sequences distributed along the path of the fault cable; performing gradient analysis processing on the signal intensity sequence to generate a gradient sequence with a signal intensity change rate; Identifying the position of a mutation point where the signal intensity is mutated according to the gradient value continuously changed in the gradient sequence; mapping the abrupt point position to a corresponding geographic position of the non-contact sensor in a space moving path to determine the position of a low-voltage cable leakage fault point.
6. A method according to claim 3, wherein the field adaptive calibration mechanism comprises: injecting by taking the adjusted frequency as an initial frequency, and obtaining corresponding first signal intensity; Adjusting injection frequency according to a preset step length, and respectively obtaining second signal intensity and third signal intensity corresponding to frequencies higher than and lower than the initial frequency; selecting a maximum value from the first, second and third signal intensities, and determining the frequency corresponding to the maximum value as a candidate frequency; And repeating the steps with the candidate frequency as a center and with a fine step length smaller than the preset step length until the lifting amplitude of the signal strength is lower than a preset threshold value, and determining the final stable frequency as the target working frequency.
7. The method of claim 1, wherein upon injecting a target current signal into the fault cable, the method further comprises: detecting the grounding resistance of an injection loop; And dynamically adjusting the output amplitude of the target current signal through an automatic gain control loop based on the grounding resistance so as to maintain the signal strength within a preset range.
8. A system for locating a low voltage cable leakage fault point, comprising: The fault line section positioning module is used for acquiring fault line section information of the occurrence of electric leakage when receiving a trigger signal of the electric leakage fault; The target current signal injection module is used for injecting a target current signal into the fault cable corresponding to the fault line section information, and the target working frequency of the target current signal is determined based on the cable distribution parameter and the environment interference parameter through a quantitative calculation model and a dynamic frequency self-adaptive adjustment mechanism; The non-contact signal acquisition module is used for acquiring magnetic field signals along the path direction of the fault cable by using a non-contact sensor after the target current signals are injected into the fault cable, and converting the magnetic field signals into electric signals; And the electric leakage fault point positioning module is used for determining the position of the electric leakage fault point of the low-voltage cable according to the signal intensity mutation point of the electric signal.
9. An electronic device, comprising: and a memory communicatively coupled to the at least one processor; Wherein the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-7.
10. A non-transitory computer readable storage medium storing computer instructions, wherein the computer instructions are for causing a computer to perform the method of any one of claims 1-7.

Description

Positioning method, system, electronic equipment and medium for low-voltage cable leakage fault point Technical Field The invention relates to the technical field of power system fault detection, in particular to a method, a system, electronic equipment and a medium for positioning a low-voltage cable leakage fault point. Background With the continuous expansion of the low-voltage distribution system scale and the increasing complexity of the laying environment, especially the wide application of the hidden cable, the frequent occurrence of leakage faults caused by the aging and damage of line insulation and the like, not only is the safety accidents such as electric shock and fire disaster easily caused, but also serious threat is formed to the personal safety and the stable operation of equipment. Although the existing leakage protector (Residual Current Protective Device, abbreviated as RCD) can cut off a circuit when leakage occurs, fault isolation can be realized only, fault points cannot be accurately positioned, and great difficulty is brought to subsequent investigation and repair work. In the field of positioning of leakage faults, the prior art mainly relies on two types of methods, namely a traditional manual checking means such as manual line inspection and insulation resistance meter measurement, which are low in efficiency, depend on experience and can hardly be used for a hidden line, and a detection technology based on signal injection, wherein the faults are positioned by injecting specific signals into a cable and tracking changes of the specific signals. However, the existing signal injection method mostly adopts contact measurement, needs to disconnect a line and connect equipment, and has complex operation and electrical safety risk. In addition, the low-voltage cable is often densely distributed with metal materials such as steel bars, and the eddy current effect generated by the metal materials can seriously interfere with magnetic field signals, so that the precision of non-contact measurement is reduced and even misjudgment is carried out. The reference 1 (application publication number CN 112034390A) discloses a low-voltage distribution system leakage current fault monitoring method based on Hausdorff distance, which calculates the bidirectional Hausdorff distance of residual current waveforms of adjacent monitoring nodes through an edge terminal, and constructs a mismatch matrix to realize fault section identification. The method improves the monitoring sensitivity by utilizing the characteristic of waveform difference, and avoids the problem of misoperation of the numerical value matching of the traditional single-ended electrical quantity. However, the comparison document 1 mainly focuses on macroscopic difference analysis of residual current waveforms, and fails to effectively solve the problem of accurate positioning of fault points. The method relies on synchronous sampling and topological matching of multiple terminals, is high in deployment cost and low in flexibility in a dark or complex environment, and the algorithm is focused on section-level fault identification, so that the leakage point cannot be directly positioned on meter level or even higher precision, waveform distortion caused by field metal interference is particularly difficult to restrain, and the positioning result is easily influenced by environment specificity. Therefore, the existing leakage fault positioning technology has the technical problem of insufficient non-contact measurement precision, so that the practicability is limited in complex scenes such as a hidden cable and the like, and the operation and maintenance requirements of high precision and quick response are difficult to meet. Disclosure of Invention The invention aims at the defects or shortcomings, provides a positioning method, a system, electronic equipment and a medium for a low-voltage cable leakage fault point, and can solve the technical problem that the existing leakage fault positioning technology has insufficient non-contact measurement precision. The invention provides a positioning method of a low-voltage cable leakage fault point, which comprises the following steps: and responding to the triggering signal of the leakage fault, and acquiring the fault line section information of the leakage. And injecting a target current signal into the fault cable corresponding to the fault line section information, wherein the target working frequency of the target current signal is determined based on the cable distribution parameter and the environment interference parameter through a quantitative calculation model and a dynamic frequency self-adaptive adjustment mechanism. After the target current signal is injected into the fault cable, a non-contact sensor is used for collecting magnetic field signals along the path direction of the fault cable, and the magnetic field signals are converted into electric signals. And determining the po