Partial discharge (PD) measurement using electromagnetic wave by antennas i
s a promising technique to diagnose the insulation performance of GIS. In o
rder to establish high-sensitive diagnosis technique of GIS insulation, fre
quency characteristics of electromagnetic wave, which are determined by GIS
apertures such as insulating spacers and bushings, should be clarified.
In this paper, we measured the electromagnetic wave radiated from different
GIS apertures and also analyzed it using transient analysis program "PSpic
e." Comparing the measurements with the theoretical analyzes, we investigat
ed the relationship between the GIS aperture configuration and the radiated
electromagnetic wave spectrum from the aperture. We also discussed how the
aperture condition contributed to the radiation characteristics of electro
magnetic wave. Finally, we concluded that the electromagnetic wave radiated
from GIS aperture was based on different radiation mechanism in frequency.