Effect of Al doping on nonlinearity and residual voltage of ZnO ceramic resistor

ZnO arresters are widely used in DC circuit breakers to absorb energy in the process of breaking short-circuit fault currents because of their excellent current carrying capability and excellent nonlinearity. In this paper, some samples of ZnO ceramic resistors with different electrical properties were prepared by changing the doping amount of Al content. The I-V characteristics of the sample were tested. By studying the I-V curve, the grain resistance and the voltage at the grain boundary were calculated. The relationship between nonlinearity and and residual voltage is obtained. It is considered that the residual voltage is affected not only by the residual voltage of the grain but also by the breakdown voltage of the grain boundary.