The Design of a Sensor for Monitoring Partial Discharge within a Joint of Power Cable

A wideband capacitive sensor has been designed, aimed at the structural characteristics of cross-linked polyethylene power cable and defects within the insulation. An analytical model has been established based on the capacitance and the antenna coupling. All the elements which have an influence on the property of sensor are analyzed, and the structure and the parameter of sensor are optimized, through a derivation of transfer function, a calculation of impedance characteristics and an analysis of the response of square wave. Partial discharge signals produced by various defects of insulation are measured and analysis in the lab.