実規模GILにおける各種センサの部分放電受信スペクトラム特性比較

抄録

Long-distance SF₆ Gas Insulated Transmission Line (GIL) has been developed for huge power supply in future. To enhance the reliability of GIL operation and to diagnose the insulation performance in GIL, partial discharge (PD) measurement is one of the expected technique and thus we measured the frequency spectrum of PD current pulse and that of electromagnetic wave radiated from PD on full scale, long distance 275kV SF₆ GIL.
In this paper, by analyzing these spectra we carried out the comparative study of different types of PD sensor like UHF, foil electrode and search coil sensors, as well as the attenuation characteristic of PD signals in long distance GIL. The result of the experiment shows that under 100MHz, both UHF sensor and foil electrode sensor have enough high sensitivity, whereas above 100MHz, UHF sensor has better sensitivity than other sensors. Furthermore, we estimated that the attenuation ratio of electromagnetic spectrum measured by UHF sensor was 5.9 [dB/100m] in the frequency range from 200 to 500MHz. Finally, we concluded that UHF sensor has the best performance from the viewpoints of sensitivity and frequency characteristics, for PD measurement in GIL.