A comparison of AC and DC surface discharges characteristics for silicone rubber

High voltage direct current (HVDC) transmission technology has been known as a green energy transfer technology to make large capacity transmission possible and allow towers to be compact with low power loss and lower insulation level than AC. However the overhead insulators of HVDC capture a lot of dirty materials due to specific static electricity phenomenon of DC differently from AC scheme. As this change of surface characteristics not only reduces water repellent due to leak current but also leads destructions such as tracking, erosion, etc. HVDC overhead insulators significantly require contamination resistance performance. Thus this paper has considered surface discharge and tracking characteristics under AC and DC with silicone rubber that has been widely used as an insulation material. As DC has constant minor flame discharge and electrical corrosion, metal is ionized by the current and the electrode is consumed. To the contrary, as AC is alternating electric field, it has occasional discharges with short discharging time, less erosion and little mass lost on the electrode.