PARTS OF SF6 POWER CIRCUIT BREAKERS BASIC INFORMATION

SF6 gas circuit breakers were first developed in the early 1950s by Westinghouse Corporation, following the discovery of the excellent arc quenching and insulating properties of SF6 gas.

Both live tank and dead tank designs were introduced from the late 1950s into the 1960s. SF6 remains the dominant insulating and arc-quenching medium at higher voltages (72.5 kV and above) even today.

Dead tank SF6 gas circuit breakers were incorporated into gas-insulated substations (GIS) up to 800 Kv from the mid-1960s through the present. Gas insulated substations offer space savings and environmental advantages over conventional outdoor substations, using the reduced insulation gap requirements of SF6 gas.

SF6 gas circuit breakers were initially of the two-pressure type, in which high pressure gas for interruption is compressed and stored for later interrupting duty.

Later designs employed the puffer principle, in which interrupting pressure is developed during the contact motion itself, and no high pressure gas is stored.

The latest designs of SF6 gas circuit breakers utilize the arc thermal energy itself to develop the interrupting pressure; these designs are referred to as self-blast or thermal-assist circuit breakers.

Below are the parts of Dead-tank SF6 circuit breaker.