Paper Title
Use of Pulse Propagation Behavior for MV PD Source Localization in Medium Voltage Cables

Partial discharge (PD) is caused in the insulation system such as medium and high voltage cable due to a variety of defects. Such discharges, if allowed to continue, can degrade the insulation causing its ultimate breakdown. Online PD (OLPD) measurements are now extensively being used for condition based maintenance programs. The partial discharge initiates a current pulse which propagates simultaneously in the cable core and the cable earth screen with opposite polarities. The PD pulses tend to propagate away from the source and their magnitudes become smaller due to attenuation. Moreover, the high frequency components are attenuated more during propagation in the cable. Thus, PD associated pulses undergo changes in magnitude and waveform during propagation. Direct and reflected pulses can be used for cable length measurement and PD source localization. PD propagation studies in cable networks are useful for online PD source localization purposes. This paper discusses, cable length measurements using direct pulse acquisition in OLPD measurements. In addition to partial discharge pulse polarity tracing method helps to identify the direction of arrival of partial discharge pulses. Such polarities as well as peak pulse magnitudes captured by HFCT sensors during the OLPD measurements are studied in this paper. Lab studies were performed using online PD measurement systems and medium voltage cable networks, and the results are reported in this paper to point out how PD pulse behaves in single core cable and how it can help in PD source localization in OLPD method. Index Terms—Polarity, Tracing, Direct Pulse, Partial Discharge, HFCT, Length.