Influence of Different Voltages on Charge Characteristics of SiR/SiC Composites for HVDC Cable Accessory Insulation

The electric field distortion and charge movements are effected by polarity-reversal voltage in HVDC cable system. The electric field can be uniformed by the semiconductive material and the charge movement characteristics can also be regulated. This paper investigates the influence of polarity-reversal voltage on charge movement characteristics in SiR/SiC composites for DC cable accessory SiR insulation at various temperatures. The charge movement process of the composites under polarity-reversal voltage and DC voltage at temperature ranges from 30 to 90 °C are obserced by surface potential decay (SPD) method. Studies have shown that the increase in temperature and the content of SiC improve the conductivity of SiR/SiC omposites. This can obviously weaken the accumulation of charges. There are cases where the charge at the centre of the sample is less than outside because of the high surface charge decay rate in the voltage polarity-reversal process,