Air Insulation Design of UHV Stations Based on Switching Surges

Switching impulse tests were performed on large air gaps to determine the insulation strength of future UHV stations. Rigid buses, both suspended and post insulator supported, were tested for heights up to 15 m. Phase-to-phase arrangements were tested by simulating substation configurations. This includes horizontal crossed buses and the ring-to-bus configuration of parallel buses, for interphase clearances up to 16 m. This study also included the effects of other parameters such as wave shape, bus size, shape of ground support structures and proximity effects.