Surface flashover characteristic of disc-type spacer system initiated by wedge shaped gas gap and its improvement

The surface flashover characteristics initiated by local field intensification are investigated for lightning impulse, switching impulse, and AC voltages, using disc-type model spacer systems with a wedge-shaped gas gap formed between the spacer flange and the earthed sheath end. The surface flashover voltages of the systems are evaluated by simple theory in SF/sub 6/ gas and compared with experimental results. Thin dielectric coating of a low-permittivity material on the sheath ends and the shielding of sheath ends which protrude inwardly are effective in improving the dielectric performance of the system.<
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