Evaluation of a Low-cost Capacitive Non-intrusive Sensor for the Detection, Localization and Identification of Defects in MVAC Cables

Partial discharges (PDs) monitoring is a common tool for diagnosing electrical systems. An innovative, low-cost sensor for distance detection and positioning of partial PDs has been developed. An ambitious challenge for this PD monitoring system is to predict dielectric breakdowns on a grid and particularly in MVAC cables. The first part of the article demonstrates the proper functioning of this sensor on a test bench. In a second part, monitoring measurements of PD activity issued from artificial defects are presented. PD initiated in submillimetric cavities were collected. Parameters and PD patterns have been interpreted with the aim to correlate with the electrical treeing propagation until breakdown. The final section is dedicated to a concise review of electrical treeing monitoring. Analysis of existing approaches are presented, as well as the interesting opportunities offered by the sensor.