Interference Research of Partial Discharge On-line Detection In Subway Direct Current 1500V Cable

摘要

The subway direct current 1500V feeder cable is a very important equipment in the track traffic system. It has enormous social benefit that using on-line detecting partial discharge in the cable to assess its insulating status. The electric wiring of the subway direct current cable is very special. Based on analysis of the electric structure of the subway draught system, this paper discusses the potential interference source in detecting partial discharges in the direct current cable by laboratory simulation and field measurement. The results of laboratory simulation and field measurement show that the main interferences involve rectifying pulse generated by the rectifying equipments, partial discharge pulse transmitted from the AC side, partial discharge pulse generated by the other equipments on the direct current side, stochastic pulse interference, current pulse generated by the frequency modulation of the locomotive, interference generated by electric equipment and white noise. In allusion to the aforementioned interference signal, the corresponding anti-interference steps are given based on analyzing theirs time domain and frequency domain characteristic in detail integrated with the electric structure of cable. The work provides a reference for anti-interference in subway DC 1500V cable discharge on-line detection.