Partial Discharge Test

Test method

A partial discharge is an electrical discharge that partially short-circuits the insulation between two electrodes. The purpose of the partial discharge test is to verify that the cable insulation is free from any defects caused by partial discharges above a specified magnitude, typically 5pC at the voltage specified in the cable standard.

To carry out the partial discharge test, equipment is required that includes a high voltage power supply with suitable capacity for the length of the test cable, a voltmeter suitable for high voltages, a partial discharge measuring device and a discharge calibrator.

The test procedure to test partial discharge involves applying a test voltage between the conductor and the cable screen. The voltages are determined according to the relevant cable standard.