Sensitivity Assessment Procedure for Partial Discharge Measurements on Transmission Class Cables

Over the last decade, partial discharge testing has gained acceptance as a valid diagnostic tool for condition assessment of cable insulation. As a result, PD testing has become the corner stone of most asset management programs. However, the results obtained from a partial discharge test depend not only on the conditions under which the test was performed but also on the test equipment itself including the type of sensor used and its location. The issues related to the relationship between the actual discharge, induced charge and apparent charge is well understood. The issues related to attenuation and dispersion of partial discharge pulses traveling along a transmission line are also well understood. Considering these, this paper proposes a calibration procedure for field-installed cable joints which can be used for assessing the sensitivity of a partial discharge measurement for an installed system using both integrated sensors as well as external PD sensors.