热电驱动下断路器碳陶瓷合闸电阻的导电机理研究

Closing resistors are critical components in ultra-high-voltage circuit breakers, however, their dynamic conduction under pulsed-energy injection remains poorly understood, thereby limiting energy-handling capability and compromising breaker reliability. This study combines pulsed-energy injection experiments and thermoelectrically coupled simulations to elucidate the electrothermal response and conductivity evolution of carbon-ceramic resistors. By correlating macroscopic resistance variations with microscopic conductive-chain dynamics, the conduction process is divided into four distinct stages: transient conduction, sustained decline, steady fluctuation, and gradual recovery. A thermoelectric-driven mechanism governing the conductive network is proposed. The microscale network consists of non-conductive, discontinuous, and continuous conductive chains, whose activation is jointly controlled by both the electric field and temperature. Strong electric fields induce tunneling conduction in discontinuous chains, whereas thermal expansion effectively reduces contact resistance in continuous chains. The individual and coupled influences of temperature and electric field are quantified by numerical fitting of the recovery resistance versus temperature and transient resistance versus field. Results reveal a pronounced thermoelectric synergy with clear energy dependence. Under low-energy injection, coupling enhances carrier excitation, yielding resistance reductions exceeding the sum of individual thermal and electrical contributions. Under high-energy injection, conductive-chain saturation suppresses further synergy, leading to smaller-than-additive resistance reductions.