On-site Applications of the VHF Partial Discharge Detection Method for the Underground Power Cable Terminations

Extra-high voltage underground power cables are adopted as the major transmission cable system in most metropolitan cities of Korea. As a result, any operational malfunctioning thereof may cause social and economic damage and the ripple effects as well as enormous time and financial costs. Moreover, as the EHV underground power cables in Korea have operated for a prolonged time, the necessity for regular check-ups and other preventive diagnostics becomes more critical. One of the preventive diagnostic methods is to detect the VHF partial discharge that could occur inside terminations or the cables, and this method has been conducted to decide the current states of underground power lines. Conventional detection methods for the partial discharge of the underground cables utilized the detection of the high-frequency ranges. Contrary to them, this paper described the method of detecting and analyzing the partial discharge for the underground transmission cable terminations at the VHF ranges, and this method can minimize the extraneous noise effect. Also, on-site application of the method is conducted in this paper in order to test reliability.