Electrical test results of UHV airgaps and insulator configurations

The paper summarises BPA´s (Bonneville Power Administration) 60 Hz and impulse test results on UHV airgaps and insulator configurations performed to evaluate the insulation requirements for 1100 kV transmission lines. Information is presented on the effects of switching impulse waveshape and polarity, the number and type of insulators, grading devices and tower configurations, weather conditions, and the performance of prototype 1100 kV insulator configurations for 60 Hz and switching impulse voltage under artificially contaminated conditions.