Electrical Breakdown of Long Gaps in Sulfur Hexafluoride

The electrical discharge characteristics of SF6 are discussed theoretically in relation to the field dependence of the ionization coefficient a and the electron attachment coefficient The results are compared with the characteristics of air. A simple theoretical formulation of breakdown or corona inception voltages of gaps in SF6 is derived. The formulation has been examined by experiments on several electrode configurations. At low pressures of less than 4 atm, the agreement of the theoretical and the experimental results is fairly good. The breakdown voltage decreases from the theoretical estimation at higher pressure.