Phenomenon and Mechanism of Positive Synergistic Effect of SF6/N2 Mixed Gas

With the aim to investigate the insulation properties of SF
6
/N
2
mixed gas which has been commonly applied in power system, it is requisite to establish a method to improve the insulation properties of SF
6
/N
2
mixed gas. The positive synergistic effect of mixed gas could be a solution so the conditions that the positive synergistic effect appealed were investigated by experiments in this paper. The mechanism of the positive synergistic effect was analyzed. It is ascertained that the positive synergistic effect appealed when the pressure is at 0.2 MPa for 30%SF6/70%N2 mixed gas in an electric field that is not uniform under AC voltage. The positive synergistic effect appealed with a mixing ratio from 30%-40% at 0.2 MPa. The positive synergistic effect did not appeal under lightning impulse in the same conditions. The analysis indicated that the corona stabilization effect around the needle electrode contributes to the positive synergistic effect of SF
6
/N
2
mixed gas.