Breakdown and Partial Discharge Inception Voltages Characteristics in N2, CO2, Dry air and SF6 at Lightning Impulse Voltage

The authors investigated partial discharge inception voltages (PDIVs) and breakdown voltages (BDVs) of the potential gases like N2, CO2 and dry air as well as SF6 under the quasi-uniform field (clean condition) and the non-uniform field (particle condition). The non-uniform field was formed by a metallic particle with 3 mm in length which was attached on the high voltage sphere electrode. The gas pressure was changed from 0.1 MPa to 0.5 MPa, and standard lightning impulse voltages were applied. As a result, under the quasi-uniform field, the negative minimum BDVs of all the gases were lower than those of the positive ones in general. The negative minimum BDVs of the potential gases ware about 35% to 45% of that of SF6. Under the non-uniform field, the 50% PDIVs of SF6, CO2 and dry air…