Surface Flashover Characteristics of Cylindrical Epoxy Resin Insulators in CF3SO2F/N2 Mixture
CF3SO2F/N2 mixture is a potential SF6 substitute gas,however,few researches on its surface flashover charac-teristics are available in the literature.In this paper,combined with the existing research results of CF3SO2F,the liquefaction temperature,operating conditions,application costs and other aspects were taken into account,and CF3SO2F/N2 mixture was studied.Consequently,an experimental platform for surface flashover under different voltage forms was established,including DC voltage,power frequency AC voltage,and lightning impulse voltage.The surface flashover characteristics of gas mixture under uniform electric field were studied and compared with SF6.It is found that the surface flashover voltage under different voltage forms increases with the rise of gas pressure.Under DC voltage,the 12％CF3SO2F/88％N2 mixture with surface flashover voltage of 0.8 MPa can reach more than 90％that of 0.5 MPa SF6.Moreover,under power frequency AC voltage and lightning impulse voltage,surface flashover voltage of the former can be close to 70％and 90％that of the later,respectively.Additionally,the surface morphology of the samples after surface flashover is compared and analyzed.It is found that the shape and color of the flashover traces on the sample surface are different in the gas mixture under different voltage forms,and the flashover along the power frequency AC voltage causes the most damage to the sample surface.The conclusions of this paper can provide references for insulation designs of CF3SO2F insulation equipment.
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