PD signal propagation characteristics in GIS and its locationsystem by frequency components comparison

摘要

Propagation characteristics of partial discharge signal in GISnwere investigated in a laboratory and at a 300 kV undergroundnsubstation. The laboratory test indicates that signal damping can benattributed to two major mechanisms; reflection due to irregularity ofncharacteristic impedance such as spacers, and the mode shift from TEM tonTE or TM. Tests at the substation show that the signal damping phenomenanare independent of propagation direction, and the mode shift gives risento a large signal damping. The major higher mode seems to be TE11n. Amplitudes of observed waveforms using narrow-band filters thatnagree well with the corresponding frequency components observed with anspectrum analyzer show irregular or random behavior depending upon theirnobservation point. This indicates that narrow-band filters do not seemnto be suitable for a partial discharge location system by a frequencyncomponent comparison, and the realizability of the system usingnbroadband filters instead is discussed