Calibration of on-line partial discharge measuring system using Rogowski coil in covered-conductor overhead distribution networks

摘要

Partial discharge (PD) detection has been regarded as one of the most effective on-line predictive maintenance test and diagnostic tool for the condition monitoring of high voltage (HV) equipment. In this study, a methodology for detecting on-line PDs produced because of falling trees on the covered-conductor (CC) overhead distribution lines is introduced and calibration of PD measuring system is carried-out. The Rogowski coil is used as a PD sensor which is non-intrusive and superior to the conventional PD detectors. The experimental set-up was arranged in the HV laboratory for real-time analysis and a pulse calibrator was used to calibrate the PD measuring system. Few real-life PD measurements have been taken and it is revealed that PD magnitudes and signals bandwidth may vary under various circumstances. The calibrated on-line PD measuring system can be used to detect and measure the amount of PDs produced because of falling trees on CC lines, thus improving the reliability and safety of the distribution networks as well as reducing visual inspection work after storms.