765 kV Externally Gapped Line Surge Arrester (EGLA): Steps in Design, Testing & Integration
Externally gapped line arresters have already been applied for years for lightning protection of overhead lines up to 550 kV maximum system voltage. This presentation describes development, design and installation of the first EGLA for UHV systems with maximum voltage of 800 kV (i.e. 765 kV operating voltage) and tested according to the latest standard, IEC 60099-8, ed. 2.0. It also discusses important challenges as well as basic functional requirements, such as severe service conditions, difficult insulation coordination due to existing tower design, high-energy ratings and difficult installation accessibility. Finally, recommendations and comparisons are made with alternative solutions.