Study on Space charge Transport and accumulation characteristics of XLPE Cable during DC Operation

Changing the AC cable line to DC operation can make full use of the original transmission line corridor and improve the transmission capacity of the line. However, the electrical characteristics of insulating media in DC operation are different from those in AC operation. In order to study the electric field distribution and space charge accumulation characteristics of AC-AC-linked polyethylene (XLPE) cable under DC voltage, the temperature field, electric field and space charge characteristics of cable insulator under different temperature differences were studied based on bipolar carrier model. It is found that the electric field distribution and space charge accumulation characteristics in the cable insulation are greatly affected by the temperature gradient (temperature difference). After being pressurized for a long time, the electric field distribution in the insulator will be obviously reversed, that is, after AC voltage is changed to DC operation, there will be a serious distortion of the electric field on the outside of the insulating layer.