UHV Transmission Tower Insulation Tests

To provide data for design of UHV transmission towers from which system design altemates can be evaluated, switching-and lightning-impulse tests were performed on simulated full-scale transmission towers having a minimum strike distance from 16.3 to 27.8 feet. Although it appears economically undesirable to design 1100-to 1300-kV systems to "withstand" a 2.0-pu switching surge, as was done at 550-kV transmission, these tests indicate that this design is technically feasible for 1100-kV transmission. The economic solution appears to be at design levels of 1.5 pu or less.