Outage-free Retrofit Scheme of Substituting SF6/CF4 Gas Mixture in SF6 Circuit Breakers
SF6 is widely used in power equipment owing to its excellent insulation and arc extinguishing performances.In order to meet the arc extinguishing requirements,SF6 gas is often maintained at high pressure inside the equipment,and thus prone to liquefaction under undue pressures and low ambient temperatures.In recent years,during winter cold waves,the equipment in State Grid Urumqi Power Supply Company repeatedly encountered circuit breaker SF6 liquefaction and locking,and the resultant rising risk of breaker inaction or even override trip.In view of this,the present work tries the method of substituting SF6/CF4 gas mixture instead of pure SF6 as an insulating medium to address insula-tion gas liquefaction.And more importantly,it proposes and practically verifies a power outage-free retrofit scheme for this substitution.
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