Tools for partial discharge testing MV cables and plant

Probably the most useful diagnostic for high voltage insulation is a measurement of partial discharge (PD) activity. Even for insulation systems which are designed to be discharge free (such as polymeric cables, enclosed busbars etc), where PD activity is nevertheless present, and hence potentially responsible for insulation deterioration, measurements of PD activity are vital to avoid plant failure. As the PD voltages tend to be small, other electromagnetic interfering signals are always a problem. In addition, there may be many PD sources in a power network, all contributing to the overall measured pulses. The separation and localisation of the PD activity is still a major task in improving the quality of the measured PD data.