Optimization of Air Insulation Clearances for EHV/UHV Transmission Lines

This paper presents the results of the study conducted on 400 kV, 800 kV and 1200 kV transmission line insulator strings and conductor–tower window geometries with an aim to optimize air insulation clearances. Laboratory investigations were carried out to evolve the switching impulse performance of phase–to–earth and conductor–window confi gurations in addition to the reference rod plane air gap lengths in EHV/UHV range. Tests were conducted on 400 kV, 800 kV and 1200 kV line confi gurations of I, Vee, double Vee, etc., by simulating the tower windows. The paper also presents results of the study on optimization of conductor-tower air insulation clearances for adoption in 1200 kV AC transmission lines using 8 bersimis conductor bundle carried out for establishment of 1200 kV Test Station at BINA, Madhya Pradesh, by Power Grid Corporation of India. Results of the tests and the data presented in the paper will be useful for design of phase-to-ground air insulation for adoption in EHV/UHV Transmission lines.