方形波インパルスによる高気圧N_2およびCO_2ガスの短時間領域絶縁特性とその定量的評価手法 [in Japanese] Short Time Region Sparkover Characteristics of Compressed N_2 and CO_2 using Square Impulse and their Quantitative Estimation Method [in Japanese]
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SF<sub>6</sub> is used as a main insulation gas for gas-insulated switchgears (GIS), but it has recently become a gas to be restricted because of its greenhouse effect. Up to now, we have studied the insulation characteristics of compressed N<sub>2</sub> and CO<sub>2</sub> as a possible SF<sub>6</sub>-alternative gas. As GIS are subjected to very fast transient voltage due to incoming lightning surges or at disconnector switching operation, it is necessary to clarify the sparkover voltage-time (V-t) characteristics in the short time region. In this report, we describe the V-t curves ranging from 30ns to 10μs for high pressure (0.6 and 1.0MPa) N<sub>2</sub> and CO<sub>2</sub> obtained by applying square impulse voltage. We next studied the V-t curves for standard lightning and oscillating impulses for the same experimental conditions. Based on these results, we investigated the possibility of quantitatively estimating of the V-t curves for these waveforms by applying the "equal-area criterion". The minimum sparkover voltage estimated by the criterion very well agreed with the measured characteristic in all conditions studied, and thus it has become clear that the quantitative estimation of the sparkover characteristics is possible for high pressure N<sub>2</sub> and CO<sub>2</sub>.
- IEEJ Transactions on Fundamentals and Materials
IEEJ Transactions on Fundamentals and Materials 128(4), 165-171, 2008-04-01
The Institute of Electrical Engineers of Japan