A pulse wave velocity correction method for partial discharge monitoring of high-voltage cables

Abstract

The invention discloses a pulse wave velocity correction method for partial discharge monitoring of high-voltage cables. The method first injects coupling pulses into the grounding joints of three-phase cables in the current grounding box based on electromagnetic coupling, and then grounds the adjacent grounding boxes of the current grounding box. The grounding joint of the three-phase cable in the box collects the coupling pulse, calculates the pulse wave speed according to the cable length and the transmission time of the coupling pulse, and then fits the load of the three-phase cable and the pulse wave speed to the coefficient of the wave speed load curve. The wave velocity load curve corrects the pulse wave velocity under real-time load to obtain the corrected pulse wave velocity. The corrected pulse wave velocity can be used for partial discharge positioning to make the positioning result more accurate. The invention can accurately correct the pulse wave speed according to the load fluctuation, which is beneficial to the accurate positioning of the partial discharge position.

Description

technical field [0001] The invention relates to the technical field of cable insulation detection, in particular to a pulse wave velocity correction method for partial discharge monitoring of high-voltage cables. Background technique [0002] Partial discharge monitoring of high-voltage cables is of great significance for discovering early defects in cable insulation. At present, high-frequency current transformers (HFCTs) are usually installed at the cross-connected grounding box for partial discharge monitoring of high-voltage cables to collect partial discharge signals, and different signals are collected through optical fibers. The time base of the acquisition point is synchronized. [0003] The accuracy of locating cable defects through partial discharge is very dependent on the propagation speed of the discharge signal in the cable. At present, the pulse wave speed cannot be accurately obtained in the cable partial discharge monitoring, and 172m / μs is often used for re...

AI Technical Summary

Problems solved by technology

[0003] The accuracy of locating cable defects through partial discharge is very dependent on the propagation speed of the discharge signal in the cable. At present, the pulse wave velocity cannot be accurately obtained in cable partial discharge monitoring, and 172m / μs is often used for related calculations.

However, the wave velocity of the pulse in the cable is affected by the temperature of the medium, so the wave velocity is often different at different times due to the load fluctuation of the cable.

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