Effect of Micron-scale and Nanoscale Hybrid Boron Nitride Fillers on AC Breakdown Performances of Polytetrafluoroethylene

As an important part of power equipment, high voltage circuit breakers play an important role in circuit breaking and isolating. However, during the breaking process of high voltage circuit breakers, arcs and recovery voltages are generated between the moving and stationary contacts, which may cause serious ablation and breakdown of the nozzles in the circuit breaker, shortening the life of the circuit breakers. Therefore, nozzles with superior performance are urgently needed. PTFE filled with different proportions of micron-BN and nano-BN was prepared in this paper to study the effect of hybrid fillers on the AC breakdown performance of PTFE. Scanning electron microscope (SEM) is used to characterize the dispersion state of micron-BN sheets and nano-BN sheets in PTFE matrix. The Thermally stimulated depolarization currents (TSDC) experiment is used to test and calculate the trap parameters of the sample. The AC breakdown experiment is used to test the breakdown strength of the specimen. The relationship between the breakdown performance and the change of trap parameters is discussed. And these factors are considered to be closely related.