Research of Carbon Ceramic Materials for Closing Resistors by Hot Pressing Sintering

Abstract The closing resistor is an important component of high-voltage circuit breakers. Its function is to withstand the L-C oscillation in the power grid during line closing, convert electrical energy into thermal energy, and release it to the external environment to achieve the purpose of suppressing closing overvoltage. The ceramic resistors currently used in circuit breakers are mainly resistance sheet products from a British company. The sintering method for preparing resistance sheets is pressureless sintering, but it cannot be ignored that this sintering method has problems such as high sintering temperature, long insulation time, and abnormal grain growth. Considering that hot pressing sintering can produce ceramic products with higher density and better performance, this paper uses hot pressing sintering to prepare carbon ceramic closing resistors, and compares their performance with resistance sheets of the same specification from a British company. The experimental results show that the density of resistance sheets prepared by hot pressing sintering is much higher than that of British company products, and their conductivity is better. Compared to products from British companies, the thermal conductivity has doubled and the bending strength has increased by nearly twice.