Mistakes During Partial Discharge Measurements of High Voltage Capacitors

Abstract

This paper presents some common mistakes which should appear during partial discharge measurements in ca se of high voltage capacitors. The partial discharge measurements are a very sensitive measurement type, which have to be done in a shielded chamber. This kind of measurement should be disturbed by conducted low frequencies electromagnetic noises. For example the switching power supply of a Computerized Numerical Control machine, produce a high level electromagnetic noises, which some times is higher than the partial discharge produced by high voltage capacitors. Another kind of mistakes which should appear is the poor cable connections in the measurement system, which determines some discharges which appear at poor cable connections. This kind of mistake determine a very high amount of partial discharge measurement results. This kind of mistakes determine false measurement result or make impossible the measurement process, which affect the credibility of the measurement laboratory.