Research on arc ablation resistance of PTFE improved by introducing inorganic filler

Polytetrafluoroethylene (PTFE) is the nozzle material of high voltage SF₆ circuit breaker, and the life of circuit breaker is influenced directly by arc ablation of PTFE nozzle. Arc ablation resistance and dielectric property of PTFE composite are studied as adding different filler, including Al₂O₃, BN, TiO₂, and MoS₂. The result indicates that arc ablation resistance can be greatly improved by introducing inorganic filler. When filler type is different, the sequence from big to small of arc ablation quantity of PTFE composite is: compound MoS₂ PTFE, compound TiO₂ PTFE, compound Al₂O₃ PTFE, compound BN PTFE. Relative dielectric constant of PTFE composite is increasing along with increment of filler, and decreasing as temperature rising. Dielectric loss angle tangent is increasing as increment of filler addition and temperature rising. The result of arc ablation resistance is analyzed using orthogonal design software. The analysis result reveals that arc ablation quantity is influenced greatly by addition of filler, next by filler particle size, and thirdly by the interaction of filler particle size and PTFE particle size, and the least by PTFE particle size.