The effects of moisture and gaseous additives on SF6 recovery characteristics

Abstract

SUMMARYIn order to investigate the intrinsic recovery characteristics of SF 6 an idealized model-breaker experiment is designed. The experimental simulation of the interruption phenomena offers the possibility to study the evolution of the free-decaying plasma dielectric strength against the recovery time. The effect of gaseous additives such as air, nitrogen and oxygen on the SF 6 recovery characteristics has been researched. The obtained recovery curves show distinct phases as for pure SF 6 . The influence depends on the gaseous additive nature and its proportion to the gaseous mixture. The presence of water vapor (humidity) in the breaking chamber is proved to be a degradation agent of the SF 6 insulating and recovery properties. Both dielectric and post-arc recovery studies show that the gas dielectric strength reduces with the increment of the humidity concentration.