An Improved Directional Sensor for On-line Partial Discharge Measurement in Overhead Covered Conductors

Partial discharge is a symptom of the insulation condition of covered conductor lines and is effective for their predictive maintenance. Accordingly, there is increasing interest in identifying the traveling direction of partial discharge pulses in covered conductor lines in an effort to assist the location of the partial discharge source. In this article, a simple, convenient, and inexpensive sensor is designed to identify the traveling direction of partial discharge pulses. This improved sensor mainly consists of a pulse current transducer (an air-cored Rogowski coil) and a voltage coupler (two copper foil electrodes). The feasibility of this sensor is proven by software simulation and finally confirmed by both a pulse injection experiment and a high-voltage partial discharge test on a 10-kV cross linked polyethylene (XLPE) covered conductor.