Numerical Simulation of the Electric Field in HVDC GIL with Application of Surface Conductivity Gradient Material

Gas insulated systems are utilized in narrow spaces and possess advantages in reliability, low loss and power capacity. HVDC gas insulated lines (GIL) are a suitable transmission technology for electrical energy. However, under DC condition space charge accumulation occurs and may lead to enhanced electric field stress within the GIL. The interface between solid and gaseous insulation is especially sensitive for electric fields and charge accumulation. Therefore, surface functionally graded material (SFGM) is applied as a field control technique to decrease the electric field. Thus, different SFGM approaches are investigated in this work by numerical simulation to optimize the electric field distribution within HVDC GIL.