Dielectric Tests on EHV Pantograph Switches

Tests were conducted on pantograph type disconnect switches to determine their dielectric characteristics. The data includes switching surge, impulse, and power frequency tests on insulations of 1300-, 1550-, and 1925-kV BIL, and open gaps of 130, 160, 180, and 200 inches. A comparison between the pantograph gap characteristics and various other vertical gaps, as well as vertical break switch gaps, is made. The effects of water resistivity on wet switching surge characteristics of the switch insulators was investigated for a 1550-kV BIL stack. The data is useful as a guide to the application of pantograph switches for EHV.