Research on On-Line Monitoring Method of Cable Insulation Based on Signal Injection

Abstract

Underground cables are widely used in urban distribution network. The insulation state of cable is related to the safety and reliability of power supply. In this paper, a cable insulation monitoring method based on signal injection is proposed. The low frequency signal is injected and the dielectric loss parameters of the cable are obtained. The insulation state of the cable is reflected by the dielectric loss parameter of the injected signal. Considering the accuracy of the injected signal in cable insulation monitoring, double terminal sampling is adopted. The variational mode decomposition and signal entropy are used to process the sampled signal and extract the injection signal to reduce the noise interference in the sampling signal. The feasibility and effectiveness of this method is verified by simulation.