Improving UHF partial discharge location in high voltage equipment

Insulation degradation in high voltage equipment may be caused by partial discharge activity. In this paper we investigate possible techniques for improving UHF partial discharge location based on the time-of-flight measurements, which are dependent on the accuracy with which the onset of PD signals can be determined. Wavelet de-noising is discussed in the context of how the resultant waveforms are modified in a way that alters the apparent arrival times. A method based on relative increase in energy is presented for determining the arrival times which might assist with PD location accuracy in high voltage equipment. In addition, possible approaches for implementing the relative increase in energy using automated systems in several ways are discussed.