Sulfur hexafluoride circuit breaker

A high-voltage circuit breaker that uses sulfur hexafluoride gas for electrical insulation and to extinguish the arc formed when contacts separate.

Connect

Electrical arc: A sustained electrical discharge through an insulating medium, often formed when current-carrying contacts separate. The breaker must cool and extinguish this discharge during interruption.
Sulfur hexafluoride: A colorless, nonflammable gas composed of one sulfur atom and six fluorine atoms. Its insulating and arc-quenching properties are the basis of this breaker design.
Gas-insulated switchgear: High-voltage switchgear whose components are enclosed in grounded metal housings and insulated by pressurized gas. SF₆ breakers are widely used as switching components in compact gas-insulated substations.
Global warming potential: A measure comparing the heat trapped by a greenhouse gas with that trapped by carbon dioxide over a specified period. SF₆ has an exceptionally high global warming potential, making leakage consequential.
Vacuum circuit breaker: A circuit breaker that interrupts current by extinguishing the arc in a vacuum interrupter. It avoids SF₆ and is widely used at medium voltages, but serves different voltage and design needs.
Arc quenching: The process of extinguishing an electrical arc by removing its energy or preventing continued ionization. SF₆ cools the arc and captures free electrons, helping restore insulation between contacts.
Electrical insulation: The prevention or limitation of electric current flow between conductive parts. The gas insulates live components that must remain electrically separated inside the breaker.
Electrical substation: A facility that transforms voltage and switches, protects, or routes electrical power. Substations use these breakers to switch circuits and isolate faults.
Greenhouse gas emissions: The release of gases that absorb infrared radiation and contribute to warming the atmosphere. Leaks and handling losses from breakers add SF₆ to these emissions.
Air-blast circuit breaker: A circuit breaker that uses a high-pressure blast of compressed air to extinguish an arc. It is an earlier gas-blast alternative that requires compressed-air equipment.