PILC cables evaluation using on-tine PD diagnosis techniques

Results of the evaluation performed on nearly 5000 measurement points in PILC feeders are presented in this paper. The measurements were performed on-line during normal operation of distribution cables. PD measurement method presented here, uses ultra wide band (UWB) techniques for proper PD detection reducing electromagnetic noise interference. UWB PD detection is based on a very high measuring frequency range and on the use of selective sensors. Those sensors were matched to conventional detectors to produce traditional patterns for ease analysis. Obtained partial discharge patterns were qualitatively classified in order to establish cable maintenance and replacement criteria. Along with PD measurement, thermometry and load analysis results of the tested circuits were used for diagnosis improvement.