Investigation of partial discharge behaviour with alternating current and damped alternating current

Inhalt:
This article shows investigations of partial discharge (PD) in a high voltage cable system using different voltage shapes. The two sources which were used for energizing the cable system, are 50 Hz alternating current (AC) generated by a high voltage transformer and damped alternating current (DAC). Both systems can be used for PD detection with use of a standard PD measurement circuit existing of coupling capacitor and coupling device with digital signal processing. The both test circuits are described and can be used for energizing the cable to a voltage over 110 kV (greater than 1.7 U0 for the cable used in this investigation). The cable system which is used for the investigations in this work is a 200 meter long high voltage cable with two joints. PD defects can be attached to both joints and the far end termination by using an artificial PD source. PD level for defects are compared for AC and DAC. The phase relation of PD for both methods is shown. Moreover comparison of partial discharge inception voltage (PDIV) for both energizing methods is described and measurements are shown.