Cable insulation detection based on coplanar capacitive sensor

Abstract

Power cable insulation aging affects the safe operation of the power system. Detection and prediction of the insulation aging status makes it possible to replace, repair and maintain the cables in time. Coplanar capacitive sensors are widely used in non-destructive with the advantages of single-side access, adjustable signal strength and tomography capability. In this paper, capacitive sensing for the cable insulation is proposed. The presence of conductor in the cable has a big effect on the field distribution. The output capacitance was calculated by analyzing the distribution of the electric field. Then, the relationships between the sensor structural parameters and the performance indexes (sensitivity and penetration depth) were studied and the sensor structure parameters were optimized. Finally, a coplanar capacitive sensor with a flexible substrate was developed for benchmark experiments. The result shows that coplanar capacitive sensor can be used to detect the cable insulation effectively.