Surface flashover characteristics of epoxy insulator in C4F7N/CO2 mixtures in a uniform field under AC voltage

This paper reports on an investigation into the surface flashover of an insulator in a C<sub>4</sub>F<sub>7</sub>N/CO<sub>2</sub> mixture which is used as an alternative to SF<sub>6.</sub> To date, no studies on this aspect have been reported in the literature. This study was done for a uniform field using a 220 kV AC experimental platform. The influence of molar fraction, gas pressure and creepage distance is reported and compared to that in SF<sub>6</sub>. The results show that small quantities of C<sub>4</sub>F<sub>7</sub>N mixed in CO<sub>2</sub> can increase the surface flashover voltage but, as the fraction of C<sub>4</sub>F<sub>7</sub>N increases, saturation of the surface flashover occurs. The relative surface flashover voltage of 13.0% C<sub>4</sub>F<sub>7</sub>N/87.0% CO<sub>2</sub> is approximately 80% that of SF<sub>6</sub>. The empirical formulae on the critical flashover electrical field has been obtained, which may be referenced in the design of environment friendly high voltage equipment.

[1]  Yannick Kieffel,et al.  Characteristics of g3 - an alternative to SF6 , 2017, 2016 IEEE International Conference on Dielectrics (ICD).

[2]  Yannick Kieffel,et al.  Green Gas to Replace SF6 in Electrical Grids , 2016, IEEE Power and Energy Magazine.

[3]  Dengming Xiao,et al.  Analysis of the insulation characteristics of c-C4F8/CO2 gas mixtures by the Monte Carlo method , 2006 .

[4]  S. Jia,et al.  Dielectric breakdown properties of SF6–N2 mixtures at 0.01–1.6 MPa and 300–3000 K , 2013 .

[5]  A. V. Tatarinov,et al.  Dielectric Barrier Discharge Processing of trans-CF3CH=CHF and CF3C(O)CF(CF3)2, Their Mixtures with Air, N2, CO2 and Analysis of Their Decomposition Products , 2015, Plasma Chemistry and Plasma Processing.

[6]  Yannick KIEFFEL,et al.  ALTERNATIVE GAS TO SF 6 FOR USE IN HIGH VOLTAGE SWITCHGEARS : g 3 , 2015 .

[7]  J. D. Mantilla,et al.  Investigation of the insulation performance of a new gas mixture with extremely low GWP , 2014, 2014 IEEE Electrical Insulation Conference (EIC).

[8]  A. Beroual,et al.  Fluoronitriles/CO2 gas mixture as promising substitute to SF6 for insulation in high voltage applications , 2016, IEEE Transactions on Dielectrics and Electrical Insulation.

[9]  R. Stryjek,et al.  PRSV: An improved peng—Robinson equation of state for pure compounds and mixtures , 1986 .

[10]  Yi Li,et al.  Dissociative adsorption of environment-friendly insulating medium C 3 F 7 CN on Cu(111) and Al(111) surface: A theoretical evaluation , 2018 .

[11]  H. Kuwahara,et al.  Factors Controlling Surface Flashover in SF6 Gas Insulated Systems , 1978, IEEE Transactions on Power Apparatus and Systems.

[12]  S. Yanabu,et al.  Investigation of the performance of CF3I Gas as a Possible Substitute for SF6 , 2008, IEEE Transactions on Dielectrics and Electrical Insulation.

[13]  A. Beroual,et al.  Effective ionization coefficients and limiting field strength of fluoronitriles-CO2 mixtures , 2017, IEEE Transactions on Dielectrics and Electrical Insulation.

[14]  A. Haddad,et al.  CF3I Gas Mixtures: Breakdown Characteristics and Potential for Electrical Insulation , 2017, IEEE Transactions on Power Delivery.

[15]  Alan H. Cookson,et al.  Review of high-voltage gas breakdown and insulators in compressed gas , 1981 .

[16]  J. Houghton,et al.  Climate Change 2013 - The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change , 2014 .

[17]  E. Kuffel,et al.  Gas Mixtures as Alternatives to SF6 Gas , 1999 .

[18]  R. A. Dougal,et al.  Mechanisms of Surface Flashover Along Solid Dielectrics in Compressed Gases: a Review , 1986, IEEE Transactions on Electrical Insulation.

[19]  K. Sasaki,et al.  ABSOLUTE DENSITY AND REACTION KINETICS OF FLUORINE ATOMS IN HIGH-DENSITY C-C4F8 PLASMAS , 1998 .