Recent evolution of high-voltage SF6 circuit-breakers

For a long time, SF₆ puffer circuit-breakers have been considered the most efficient and reliable type of interrupting switchgear. This technique was introduced by GEC ALSTHOM T&D (then DELLE ALSTHOM) at the end of the 1950s for medium voltage applications, and then extended in the 1960s to high-voltage circuit breakers. Since then, and until the end of the 1980s, it has been the dominant technique in the high voltage range. In the 1980s, GEC ALSTHOM T&D began to study a new generation of SF₆ circuit breakers which can be operated by low-energy mechanisms and which were characterized by the use of arc energy for interruption. Here, the author examines the development of tools used in the design of circuit breakers, and describe the recent evolution of high-voltage circuit breakers