Extended range of application for outdoor SF6 circuit-breakers

SF6 outdoor circuit breakers of type ELF for voltages from 72.5 to 420 kV have been in service for a number of years in numerous countries. This article reports on the extension of this range to rated voltages up to 800 kV, breaking currents up to 50 kA, the two-cycle interrupting time and on the facility for fitting closing resistors