実規模GILにおける蔀分放電電流パルスとその伝搬電磁波の同時測定

抄録

In Japan, long distance Gas Insulated Transmission Line (GIL) technique has been developed and now is being constructed for future huge electric power transmission. In GIL, if there would be a small defect such as void and metallic particle, partial discharge (PD) would occur, thus detecting PD is an effective method for insulation diagnosis in GIL. Among the PD measuring method, detecting electromagnetic wave generated by PD is one of the most effective method because PD radiates wide-frequency electromagnetic wave up to UHF.
This paper describes the experimental result of simultaneous measurement of PD current pulse and its electromagnetic wave in full-scale long distance 275kV GIL. The result, shows that firstly, PD signal with 1_??_2pC can be detected at the point of 169.5m away from PD source using UHF sensor. Secondly, the propagation velocity of electromagnetic wave in GIL is nearly equal to the light velocity. Thirdly, electromagnetic wave magnitude is attenuated about 7.5dB at the point of 100m away from PD source. Moreover, time-frequency analysis (wavelet analysis) of waveforms shows that the attenuation rate of electromagnetic wave differs depending on its frequency.