Influence of GIS structure on propagation of electromagnetic waves of partial discharge

Partial discharge process caused by GIS typical insulation defect is mainly analyzed in this study, and propagation properties of electromagnetic waves in actual GIS structure are investigated by applying FDTD algorithm and using real PD current signal as excitation source. The results show that great difference occurs between electromagnetic waves excited by PD actual current signal and that by ideal Gaussian pulse excitation and basin type insulator, shielding electrodes and three-phase common enclosure can affect the amplitude, frequency component and propagation mode of electromagnetic waves. The electromagnetic waves 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 when it propagate in breakers.