Meanwhile, the connection
cavity of GIS bus bar can be treated as coaxial resonator cavity
on the UHF wave band, and the resonance duration of
electromagnetic wave is generally tens of us orders, with its
maximum of over 10ms[3]. Inside GIS, there are high-voltage
conductors, joints, shields and basin type insulator, etc; its
structure can be classified into straight tube, L branch and T
branch. Because of different locations of PD generation, thepropagation and resonance mode of electromagnetic waves in
GIS are very complex.