The results show that great difference occursbetween electromagnetic waves excited by PD actual current
signal and that by ideal Gaussian pulse excitation; it has been
pointed out that basin type insulator, shielding electrodes and
three-phase common enclosure can affect the amplitude,
frequency component and propagation mode of
electromagnetic waves. When electromagnetic waves
propagates in GIS breaker, the time duration for signal
resonance attenuation is relatively long, and the signal intensity
is not necessarily proportional to its distance from discharge
source; the proportion of frequency components is proportional
to the diameter of GIS shell.