Comparison and Analysis of AC and DC Discharge Voltage of Cable Defects Based on Electric Heating Co-Simulation

With the wide application of high-voltage direct current (HVDC), cross-linked polyethylene (XLPE) cable may have some defects in production and operation. In the construction site, the method of using AC test voltage to detect the local defects of DC cable is lack of effective standards. At the same time, the existing research results do not provide the relationship between the co-simulation of electric heating and the initial discharge voltage of cable defects under AC and DC voltage. This makes the partial discharge (PD) phenomenon under AC test voltage difficult to correspond to the PD phenomenon under DC working voltage. Therefore, this paper uses the finite element software to simulate the joint of 320 kV DC cable under AC and DC voltage, and obtains the AC and DC voltage relationship when the defect occurs. The simulation results provide the threshold value of the power frequency initial discharge voltage and the DC initial discharge voltage when the internal defects of the DC cable occur partial discharge.