PD location in power cables using parametric models

In order to locate partial discharge in power cables, multiple pulses are detected using sensor(s) either installed at a single cable end or at both ends. The difference in arrival times of pulses originating from the same defect provides a measure for the discharge location. Multiple sources contribute to errors in the determined location, such as attenuation and dispersion introduced by the cable. Dispersion implies that the propagation velocity or cable speed is frequency dependent. As a consequence errors are introduced in the mapping of discharge sources along the cable length. Moreover, pulses spread and waveform reference points cannot be well defined, thus impeding accurate time of arrival estimation. Model-based signal processing provides a theoretical framework to deal with such inaccuracies. An efficient model-based method is proposed that enables compensation for dispersion related errors.