CN-122017460-A - Defect positioning method, device, equipment and medium

CN122017460ACN 122017460 ACN122017460 ACN 122017460ACN-122017460-A

Abstract

The embodiment of the application provides a defect positioning method, device, equipment and medium. The method comprises the steps of firstly collecting sheath current values of a target high-voltage cable at a plurality of preset positions based on a time synchronization mechanism, marking collecting positions and collecting moments, then constructing a sheath current line distribution curve for the sheath current values at the same collecting moment according to each collecting moment, constructing space-time distribution data based on the sheath current line distribution curves corresponding to a plurality of continuous collecting moments, determining space characteristic points according to the space-time distribution data, determining candidate positions of the sheath defects according to the space characteristic points, and finally determining time propagation paths according to the candidate positions of the sheath defects, and positioning the defect positions according to the time propagation paths. By the method, reliability and positioning accuracy of the detection of the defects of the protective layer are improved.

Inventors

LIN YANGRUI
WENG JIA
HUANG KAIJIE
ZENG XIANNING
XU YINGCHUN
LIN RUNJIE
WU CHAOHANG
GU YINGBIN
HUANG WEIYUE
HUANG PEIFENG

Assignees

广东电网有限责任公司潮州供电局

Dates

Publication Date: 20260512
Application Date: 20260228

Claims (10)

1. A defect localization method, comprising: acquiring sheath current values of a target high-voltage cable at a plurality of preset positions based on a time synchronization mechanism, and marking acquisition positions and acquisition moments; Constructing a sheath current line distribution curve for the sheath current value at the same acquisition time aiming at each acquisition time; constructing space-time distribution data based on the sheath current corresponding to a plurality of continuous acquisition moments along a distribution curve; Determining spatial feature points according to the space-time distribution data, and determining candidate positions of the defects of the protective layer according to the spatial feature points; and determining a time propagation path according to the candidate position of the sheath defect, and positioning the defect position according to the time propagation path.
2. The method of claim 1, wherein the time synchronization mechanism based acquisition of the sheath current values of the target high voltage cable at a plurality of locations and labeling of the acquisition locations and the acquisition times comprises: Acquiring a unified time reference signal, and taking the unified time reference signal as a global time reference for sheath current acquisition; Performing time calibration on local timing of each preset position according to the unified time reference signal at a plurality of preset positions to obtain time offset corresponding to each acquisition position, and correcting the local timing based on the time offset; and synchronously acquiring the sheath current values of the target high-voltage cable at the plurality of preset positions according to the preset sampling period.
3. The method of claim 1, wherein said constructing a sheath current profile for the sheath current values at the same acquisition time comprises: Based on the acquisition positions corresponding to the sheath current values, sequencing the sheath current values corresponding to the same acquisition time according to the spatial sequence of the acquisition positions along the laying direction of the target high-voltage cable to obtain a discrete current sampling sequence corresponding to the cable spatial position; Performing difference fitting treatment on the discrete current sampling sequence to obtain a continuous distribution function, wherein the continuous distribution function is used for representing the variation trend of the sheath current along the length direction of the cable; And determining the continuous distribution function as a distribution curve of the sheath current along the line.
4. The method of claim 1, wherein said determining spatial feature points from said spatio-temporal distribution data comprises: performing first derivative calculation on the sheath current along the space direction along a distribution curve, and taking the acquisition position with the first derivative value of zero as a curve extreme point; Performing second derivative calculation on the sheath current along the space direction along the distribution curve, and taking the acquisition position of the sign change of the second derivative value as a curve inflection point; and taking the curve extreme point and the curve inflection point as the space characteristic points.
5. The method of claim 4, wherein determining sheath defect candidate locations from the spatial feature points comprises: Based on the sheath current along the line distribution curve, respectively taking two adjacent curve inflection points as boundary inflection points, and determining a curve segment defined by the two boundary inflection points as a curve segment to be determined; obtaining the maximum value and the minimum value of the current value of the protective layer in the curve section to be judged; Judging whether the first change direction of the current value of the protective layer in the curve section to be judged is opposite to the second change direction of the current value of the protective layer in the adjacent curve sections at the two sides of the curve section to be judged; judging whether the sheath current values corresponding to the two boundary inflection points are in the interval between the maximum value and the minimum value or not under the condition that the first change direction is opposite to the second change direction; and if the sheath current values corresponding to the boundary inflection points are in the intervals of the maximum value and the minimum value, determining the space interval corresponding to the curve section to be determined as the candidate position of the sheath defect.
6. The method of claim 1, wherein the determining a time propagation path from the sheath defect candidate locations comprises: Selecting time sequence data corresponding to the sheath defect candidate position from the space-time distribution data, wherein the time sequence data comprises change information of a sheath current value at the sheath defect candidate position at a plurality of continuous acquisition moments; performing time sequence fluctuation analysis on the time sequence data to determine occurrence time and arrival time of abnormal change of the current value of the protective layer; determining propagation delay of the abnormal change of the sheath current value in a time dimension based on the occurrence time and the arrival time; Acquiring a propagation speed parameter of sheath current in the sheath, and determining a propagation distance of abnormal change of the sheath current value in a space dimension based on the propagation delay and the propagation speed parameter; and correlating the propagation delay, the propagation speed parameter and the propagation distance to determine a time propagation path, wherein the time propagation path is used for representing the propagation relationship of the abnormal change of the sheath current along with time and space.
7. The method of claim 6, wherein said locating a defect location based on said time propagation path comprises: Acquiring a propagation distance corresponding to abnormal change of the current value of the protective layer from the time propagation path; Determining the length of an overlapped section of the propagation distance in a space interval corresponding to the candidate position of the sheath defect, and acquiring the total length of the space interval corresponding to the candidate position of the sheath defect; judging whether the length of the overlapped section is consistent with the total length of the space section; When the length of the overlapped section is consistent with the total length of the space section, determining the acquisition position in the space section corresponding to the candidate position of the sheath defect as a defect position; when the length of the overlapped section is inconsistent with the total length of the space section and the length of the overlapped section is greater than zero, respectively determining the distance between two end point positions of the propagation distance and acquisition positions corresponding to two boundary inflection points of the candidate position of the sheath defect; And determining the acquisition position of the boundary inflection point corresponding to the minimum distance as the defect position.
8. A defect localization apparatus, comprising: the acquisition module is used for acquiring the sheath current values of the target high-voltage cable at a plurality of preset positions based on a time synchronization mechanism and marking the acquisition positions and the acquisition moments; the first construction module is used for constructing a sheath current line distribution curve for the sheath current value at the same acquisition time according to each acquisition time; the second construction module is used for constructing space-time distribution data along a distribution curve based on the sheath currents corresponding to a plurality of continuous acquisition moments; the first determining module is used for determining spatial feature points according to the space-time distribution data and determining candidate positions of the defects of the protective layer according to the spatial feature points; And the second determining module is used for determining a time propagation path according to the candidate position of the sheath defect and positioning the defect position according to the time propagation path.
9. An electronic device is characterized by comprising a memory and a processor; The memory stores computer-executable instructions; The processor executing computer-executable instructions stored in the memory, causing the processor to perform the method of any one of claims 1-7.
10. A computer readable storage medium having stored therein computer executable instructions which when executed by a processor are adapted to carry out the method of any one of claims 1-7.

Description

Defect positioning method, device, equipment and medium Technical Field The present application relates to the field of power system detection technologies, and in particular, to a defect positioning method, device, apparatus, and medium. Background The high-voltage cable is used as a key power transmission facility in a power system and is widely applied to urban power grids, industrial power supply systems and long-distance power transmission lines. Its main functions are to shield electromagnetic interference, protect the insulating layer from mechanical damage and environmental corrosion, and realize current reflow through grounding. In the long-term operation process, the protection layer may have defects due to factors such as insulation breakage, poor grounding, corrosion or mechanical stress, etc., so that the current distribution of the protection layer is abnormal. Abnormal distribution of sheath current not only accelerates insulation aging, but also can cause local overheating, discharge and even cable breakdown faults, thereby seriously threatening the safe operation of the power grid. In practical application, the high-voltage cable is usually laid underground or underwater, the environment is complex and difficult to directly observe, the traditional manual inspection is low in efficiency and high in cost, and the operation and maintenance requirements of a large-scale power grid are difficult to meet. Meanwhile, the operation load of the cable fluctuates along with time (such as day and night electricity consumption difference and sudden load change), and the spatial distribution of the sheath current can dynamically evolve. Therefore, a technical scheme capable of realizing synchronous acquisition of sheath current in time and space, accurately reconstructing spatial distribution and carrying out defect positioning by combining time propagation characteristics is needed, so that the real-time performance and accuracy of monitoring the state of the high-voltage cable sheath are improved. Current sensors are typically deployed at two or more locations on a cable, and the sheath insulation status is determined by measuring the sheath current values at each location. The common detection mode is to collect the current of each measurement position at different time points, and identify the abnormal region by comparing the current of each position or calculating the difference value of the current at the head and the tail. And in the time interval of data acquisition of each measuring position, the spatial distribution of the default sheath current is kept unchanged, and a plurality of current values acquired at different moments are regarded as spatial distribution data at the same moment. However, the solution in the prior art cannot accurately restore the real spatial distribution state of the sheath current along the cable line at any time, which results in insufficient positioning accuracy of the sheath defect. Disclosure of Invention The embodiment of the application provides a defect positioning method, device, equipment and medium, which are used for solving the problem that the defect positioning accuracy of a protective layer is insufficient because the real space distribution state of the protective layer current along a cable line at any moment cannot be accurately restored in the prior art. In a first aspect, an embodiment of the present application provides a defect positioning method, including: acquiring sheath current values of a target high-voltage cable at a plurality of preset positions based on a time synchronization mechanism, and marking acquisition positions and acquisition moments; Constructing a sheath current line distribution curve for the sheath current value at the same acquisition time aiming at each acquisition time; constructing space-time distribution data based on the sheath current corresponding to a plurality of continuous acquisition moments along a distribution curve; Determining spatial feature points according to the space-time distribution data, and determining candidate positions of the defects of the protective layer according to the spatial feature points; and determining a time propagation path according to the candidate position of the sheath defect, and positioning the defect position according to the time propagation path. In one possible implementation manner, the time synchronization mechanism is based on collecting sheath current values of a target high-voltage cable at a plurality of positions, and marking the collecting positions and collecting moments, including: Acquiring a unified time reference signal, and taking the unified time reference signal as a global time reference for sheath current acquisition; Performing time calibration on local timing of each preset position according to the unified time reference signal at a plurality of preset positions to obtain time offset corresponding to each acquisition position, and correcting the loca