Lightning Impulse Breakdown Characteristics of High-Pressure N2 as an Alternative Insulation Gas to SF6

Lightning Impulse Breakdown Characteristics in Compressed N2 and CO2 and Feasibility of their Gases' Application to Gas-Insulated Buses

“…SF 6 has been applied to a gas-insulated switchgear (GIS) and a gas-insulated transmission line (GIL) owing to its excellent insulation and interruption performances, and has contributed to the miniaturization and the achievement of high performance of equipment. Currently, global environmental problems such as global warming are important issues, and SF 6 has been identified as a greenhouse gas with a long atmospheric lifetime (1) .…”

“…Currently, global environmental problems such as global warming are important issues, and SF 6 has been identified as a greenhouse gas with a long atmospheric lifetime (1) . Therefore, recycling guidelines for SF 6 in electric power apparatuses have been studied, and the amount of SF 6 released into the atmosphere has been reduced (2) . In the long term, it is preferable to reduce the amount of SF 6 used.…”

“…Therefore, it is important to discuss the possibility of using environmentally friendly gases as an alternative insulation gas for practical gas-insulated apparatuses. Figure 1 shows dielectric strengths in different gases normalized by that in SF 6 as functions of boiling temperature. In the selection of an alternative gas, it should be noted that an artificial gas in which a high dielectric strength is achieved often has some environmental restriction.…”

“…Therefore, it is thought that high-pressure natural gases, such as air, nitrogen (N 2 ), and carbon dioxide (CO 2 ), are promising environmentally friendly candidates. In this study, we assume the complete substitution of SF 6 by a pure environmentally friendly gas (natural gas), although we also assume the use of a gas mixture as the target gas from the viewpoint of the reduction in the amount of SF 6 used (3) . To date, we have investigated the basic insulation characteristics of N 2 gas in the high-pressure range of up to 2.0 MPa (4)- (6) .…”

“…In this study, we assume the complete substitution of SF 6 by a pure environmentally friendly gas (natural gas), although we also assume the use of a gas mixture as the target gas from the viewpoint of the reduction in the amount of SF 6 used (3) . To date, we have investigated the basic insulation characteristics of N 2 gas in the high-pressure range of up to 2.0 MPa (4)- (6) . Recently, it has been reported that CO 2 has an excellent interruption performance compared with N 2 (7)- (9) .…”