CO_2ガスの非標準雷インパルス振動波形に対する絶縁特性(その2) : 5.3-20.0MHz単一振動周波に対する絶縁特性 [in Japanese] Insulation Characteristics of CO_2 Gas for Non-standard Lightning Impulse Oscillations : Insulation Characteristics under Single-Frequency Oscillations from 5.3 to 20.0MHz [in Japanese]
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To improve GIS insulation specifications, it is important to recognize the insulation characteristics under oscillatory overvoltage waveforms occurring in the field. The actual lightning surge waveform (called non-standard lightning impulse waveform) in actual substations is different from the standard lightning impulse waveform (1.2/50<i>μ</i>s). The actual lightning surge waveform generally rises steeply, however, the decay of the overvoltage is large, and the insulation requirements are not as severe as those of the standard lightning impulse waveform. Since SF<sub>6</sub> gas was identified as a greenhouse gas at COP3 in 1997, alternative insulation gases to SF<sub>6</sub> have been investigated. The CO<sub>2</sub> gas insulation is one of the candidates, which is a natural gas and has lower global warming potential (GWP). V-t characteristics with CO<sub>2</sub> showed a steep decline than SF<sub>6</sub> and the effects of oscillation on the insulation characteristics with CO<sub>2</sub> are not definite under the condition of frequency up to 4.0MHz.<br>This paper describes the insulation characteristics of CO<sub>2</sub> gas for single-frequency oscillatory waveforms with various frequencies from 5.3 to 20.0MHz and damping ratios. From experimental investigation, similarly to SF<sub>6</sub>, it might be possible to reduce the test voltage of CO<sub>2</sub> gas insulation system by evaluating actual lightning surge waveform in terms of the equivalent standard lightning impulse waveform.
- IEEJ Transactions on Power and Energy
IEEJ Transactions on Power and Energy 126(5), 539-544, 2006-05-01
The Institute of Electrical Engineers of Japan