Local-point fault detection method for marine low-voltage power cable based on FDR method

Abstract

The invention discloses a local-point fault detection method for a marine low-voltage power cable based on an FDR method. A sweep generator (1) emits a segment of sinusoidal sweeping-frequency signals to the detected cable (3), fault information of the initial end (8) of the detected cable is returned to a wave detector (2), a total-reflection voltage waveform is displayed via a display device (7) a waveform frequency difference deltaf is obtained from the total-reflection voltage waveform, a distance L between a fault point and an incident point is calculated according to a formula L=150Vp / deltaf, and Vp as a known quantity represents the speed ratio of the cable. According to the invention, possible faults as open circuit and short circuit of the marine low-voltage power cable can be located accurately, and the method is characterized by high positioning precision, simple operation, less loss, low cost, high safety and the like.

Description

technical field [0001] The invention relates to the technical field of cable fault detection, in particular to a method for detecting local point faults of marine low-voltage power cables based on the FDR method. Background technique [0002] As one of the core equipment of the power system, cables play a vital role in power distribution, transmission and a series of power services. The search and discovery of local point faults in low-voltage power cables has always been a difficult problem in the power industry. The commonly used methods are bridge method and time domain reflectometry. [0003] bridge method [1,2] The main principle is to measure the DC resistance value of the cable core wire with a double-arm bridge, and then accurately measure the actual length of the cable, and calculate the location of the fault point according to the proportional relationship between the cable length and the resistance. This method is mature in technology, the circuit is simple and...

AI Technical Summary

Problems solved by technology

[0006] The present invention is a local fault point detection method of marine low-voltage power cables based on the FDR method. Compared with the FDR method applied to communication cables in existing literature reports, the difference is that the FDR method is applied to local fault points of marine low-voltage power cables Detection, power cables do not have ideal impedance matching characteristics, different cable lengths, cable types, and dielectric thicknesses can cause different reflections at different positions of the transmission line, and all cables have unique characteristics

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