Surface Functional Graded Material Considered for DC Gas-Insulated Pipeline

To achieve improved flashover voltage and more uniform electric field (E-field) distribution on spacer surface in HVDC gas insulated lines (GILs), this paper proposed the novel spacer by depositing ZnO film onto spacer surface using magnetron sputtering method. For fabricating the optimized spacer, a baffle with designed gap was placed above the rotating spacer to control the sputtering time at different radial positions. Flashover tests were conducted under both DC and polarity reversal voltages, and the optimized spacer shows the best insulation performance, followed by the 30 min-sputtered spacer, and finally the conventional spacer. By applying such novel spacers, higher compactness and reliability can be achieved in HVDC GILs.