A direct current cable defect detection method and device based on frequency band selection and a medium

CN121933879BActive Publication Date: 2026-06-16STATE GRID SHANGHAI MUNICIPAL ELECTRIC POWER CO +1

Patent Information

Authority / Receiving Office: CN · China
Patent Type: Patents(China)
Current Assignee / Owner: STATE GRID SHANGHAI MUNICIPAL ELECTRIC POWER CO
Filing Date: 2026-03-30
Publication Date: 2026-06-16

AI Technical Summary

Technical Problem

In the field testing of DC cables, there is a large amount of broadband noise interference. The injected detection signal is limited by the power of the signal source and the attenuation effect of long-distance transmission. Its energy and amplitude are limited. At high frequencies, the attenuated detection signal may be submerged by the noise signal, resulting in serious interference with the defect detection results.

Method used

The minimum signal amplitude and output signal amplitude are obtained by an impedance analyzer set on the DC cable under test. The upper limit of the detection frequency is determined, a set of frequency calculation formulas is constructed, and the optimal test frequency band upper limit frequency is searched by an optimization algorithm based on the fitness function to determine the frequency sweep range. The frequency sweep excitation signal is then injected to locate cable defects.

Benefits of technology

Wideband impedance spectrum detection and localization within the optimized frequency band enables precise localization, effectively suppresses noise interference, and improves the accuracy of defect detection and adaptability to different operating conditions.

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Abstract

The embodiment of the application discloses a DC cable defect detection method and device based on frequency band selection, and a medium, and belongs to the technical field of cable defect detection. The method solves the problem that in the DC cable test, the decayed detection signal may be submerged by noise signal under high frequency, resulting in that the defect detection result is seriously interfered. The method comprises the following steps: determining the upper limit of the detection frequency by the minimum signal amplitude and the output signal amplitude obtained by the impedance analyzer arranged on the DC cable to be detected; constructing the fitness function based on the amplitude of the decayed detection signal corresponding to the candidate frequency point and the frequency domain amplitude spectrum of the background noise in the current cable detection environment; searching the optimal test upper limit frequency by the optimization algorithm based on the upper limit of the detection frequency and the fitness function; determining the sweep frequency range based on the optimal test upper limit frequency, injecting the sweep excitation signal into the first end of the DC cable to be detected in the sweep frequency range, and positioning the cable defect based on the received reflected signal.

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