High-voltage circuit breakers are mechanical devices used to open and close current circuits, and are the central part of switchgears. To break fault currents arising from perturbations on the transmission lines, grading capacitors are used in multi-chamber circuit breakers to ensure a proper voltage distribution between the chambers and to avoid the risk of overloading one chamber. To limit the transient recovery voltage (TRV) in single chamber circuit breakers, capacitors are used either in parallel to the chamber or connected phase-to-ground (TRV capacitors).
Maxwell Technologies develops and commercializes high-voltage capacitors for circuit breakers, including air-insulated switchgear (AIS) and gas-insulated switchgear (GIS) grading capacitors, as well as AIS or GIS transient recovery voltage (TRV) capacitors.
Maxwell grading capacitors are installed worldwide in multi-chamber circuit breakers (AIS life tank and dead tank circuit breakers or GIS) up to the highest voltage levels of 1,100 kV or 1,200 kV with two or four chambers. TRV capacitors are used either externally on dead tank or single chamber life tank circuit breakers, or internally in GIS circuit breakers as well as on generator circuit breakers.