Study of propagation effects on wideband radiated RF signals from PD activity

Location of partial discharge sources via the recording of wideband VHF/UHF signals is well known. Having obtained good accuracies, researchers in this area now aim to develop characterization techniques comparable to those of more traditional contact systems. One obstacle hindering this development is the lack of a complete mathematical understanding of the means of propagation and effects on the properties of the signals recorded. This paper puts forward an initial description of the factors involved and affecting the radiated signal. It then describes, based on initial site experiments, propagation effects which need to be considered at the time of developing algorithms for partial discharge classification based on time/frequency and apparent charge levels.