Partial discharge phenomena in SF6 gas and their sensor signals

Microgap discharge phenomena were studied using a wide-bandwidth oscilloscope and a streak camera set as well as some discharge detection sensors. The results indicate that a spark-type discharge both in SF₆ gas and in air causes electromagnetic radiation up to a frequency range of gigahertz due to its very steep front time of several nanoseconds. Its radiated waves can be easily received by the sensors. However, the electromagnetic waves radiated by a corona-type discharge have a relatively low level, and are much more difficult to detect using the antenna. Experimental results obtained with a fiberscope and photomultiplier show that the fiberscope is sensitive enough to detect such weak corona-type discharges