Study On Post-arc Dielectric Recovery Of High-current Vacuum Arc

Recently, the power system’s short-circuit current is so high that it needs a moreinterruption capability circuit breaker. Meanwhile SF6as a kind of greenhouse gas whichits application will be limited. In these factors, using vacuum circuit breaker in parallel ininterruption become a better solution. Vacuum circuit breaker is a new type of switchingequipment developed in the early20thcentury, and is widely used in many areas especiallyin electric distribution system. Vacuum circuit breaker has many advantages such aspowerful extinction capability, light in weight, small in size, long working-life,maintenance-free, and no pollution etc. Since characteristics of vacuum arc become animportant subjects of the advanced topics in the electrical switches field.The development of vacuum circuit breaker and arc characteristic of vacuum arc ininterruption are reviewed, and the mechanism and characteristics of vacuum arc areintroduced. At the same time this paper compare the similarities and the differencesbetween vacuum arc and air arc. The characteristic of vacuum arc extinguishing of post-arcdielectric recovery process are introduced. The dielectric recovery process is divided intoelectronic current damping stage and ion sheath developing stage by the maximum ofpost-arc current. At last breakdown criterion is gave.This paper combine plasma parameters and continuous transition model of currentzero moment together, develop a post-arc current and sheath growth numerical model,incorporate in software in the form of black box model, meanwhile it is the foundation offollow-up simulation. Simulation model together with breakdown criterion can be used toforecast whether the vacuum circuit breaker’s opening is success or not.The simulation result and practical circuit breaker test results are compared. Theinfluence of electrical erosion rate of materials and arcing duration time to the result ofcircuit breaker’s opening are researched. The simulation results are coincide with testresults. At last this paper points out that the high electric erosion rate of material may causethe opening failed, and in order to ensure the opening success that it should guarantee acertain arcing duration.