The Method for Cable Insulation On-line Monitoring in MV Distribution Network

Existing insulation monitoring methods have problem that the measured signal is weak and the accuracy is low. Based on the analysis of the transient fault in distribution network, a new insulation monitoring method by using transient fault signals is proposed in this paper. The insulation monitoring method utilizes the characteristics that the transient fault occurs frequently and the fault signal contains massive insulation information of the cable. Using power theory to decompose the distortion zero sequence signal generated by the transient fault, extract the components related to the cable insulation. Deriving the formula for calculating the cable insulation, and realize cable insulation on-line monitoring. The simulation results show this method is correct and effective, and improves the accuracy of insulation monitoring.