Research On The Arc Ablation Resistance Character Of Composite PTFE Using In Circuit Breaker Nozzle

In recent years, with the acceleration of UHV power grid construction, the requirement for the various components in the power system is continue to improve. To ensure the safety and the reliable operation of power system, requiring the open capacity increasing. Nozzle as the core component of HV circuit breaker, which can control arc and create high-speed gas blowing, ablation resistance of nozzle materials seriously affects the safe operation of the circuit breaker. So the research of high arc ablation resistance of nozzle material has a far-reaching theoretical and practical significance.Combined with the existing trials of the arc ablation resistance of solid materials methods and the research status of the ablation of nozzle material properties both at home and abroad, through the analysis of the characteristics of arc, the mechanism of electric arc stable combustion and ablation mechanism of nozzle material within the circuit breaker, for the study of nozzle ablation resistant properties and preliminary screening of the nozzle material, this paper propose to design a set of DC electric arc generator, for which the arc voltage, arc current, arc time and arc length is controllable. Make the nozzle material into specific cylinder models, namely inner diameter 10 mm, outer diameter 20 mm, length 10 mm. Arc burning inside the cylindrical nozzle material, and raising the material for the first time through the quality of the arc ablation losses as the nozzle material ablation resistance index.Analysis of the arc volt-ampere characteristics and the ablation factors of nozzle material by the arc. The results show that:the static volt-ampere characteristics of DC electric arc is a negative resistance characteristics, the longer the arc length, the greater the voltage of arc used to maintain stable combustion; Only change the arc time, the amount of PTFE ablation positively related with electric arc combustion time, the longer the arc burning, the larger the ablation volume change; Make the arc time and arc length unchanged, only change the arc voltage and the current, the PTFE ablation volume increases with the arc current and the arc output power increases. Filling the air in the stable burning arc, arc current fluctuation is serious, maintain arc voltage increase, material surface ablation range increases, but the ablation degree is smaller.Adding different kinds of fillers and different percentage of fillers in nozzle material, the ablation experiment was carried out, and preliminary analysis the ablation resistance of the various materials, The results show that:in the condition of arc current 21A, voltage 45V, burning time 5s and arc length 6mm, the ablation resistance of nozzle material that adding BN is better than adding MoS2+BN, and the material adding MoS2+BN is better than adding AlN; The nozzle materials adding BN and its percentage is 20% is the best. The work of this paper is suitable for the preliminary screening of nozzle material, it can provide data and test support for the selection of nozzle materials in actual circuit breaker, which has a great practical significance for the studies of the ablation resistance of nozzle materials.