Simulation of propagation characteristics of higher order mode electromagnetic waves in GIS

Numerical simulation of electromagnetic fields was performed to investigate the transmission and reflection characteristics of spacers, L-shaped sections of a GIS bus structure. The resonance frequencies of a cavity between spacers agreed roughly with experiment. The modes of electromagnetic wave are shown to transform to different modes, e.g., from TE11 to TE21 mode, after transmission and reflection through L-shaped sections of a GIS structure.