Practical experience in on-line partial discharge measurements of MV switchgear systems

On-line partial discharge (PD) monitoring has proved to he a fast, convenient, reliable and cost-effective tool in determining numerous areas of insulation deterioration within medium voltage switchgear lineups. The paper reflects the authors' practical experience and concentrates on specific areas requiring further attention, such as sensor sensitivity, sensor calibration, PD recognition and discriminating various PD sources.