Sensitivity check for on-line VHF/UHF PD detection on Transmission cables

The VHF/UHF PD detection technique is a non-intrusive method for power cable PD diagnostics. It incorporates a VHF/UHF current probe placed at the grounding of the cable and a spectrum analyzer connected to the probe. This technique however is very difficult to calibrate due to different factors affecting the frequency response of the measuring setup. In this paper the calibration procedure is described and discussed. Furthermore two examples of on-site calibration are presented, before the actual PD measurements take place. In these examples the sensitivity of the technique is also studied.