| Authors |
Feng Li ; Yang-Woo Yoo ; Dong-Kyu Kim ; Bok-Hee Lee |
| DOI |
http://dx.doi.org/10.5207/JIEIE.2011.25.3.024 |
| Keywords |
Lightning Impulse Voltage ; Switching Impulse Voltage ; Damped Oscillatory Impulse Voltage ; Breakdown Voltage-Time Characteristic ; Dry Air ; Alternative Insulation Gas |
| Abstract |
SF? gas, which has an excellent dielectric strength and interruption performance, is used in various applications such as gas insulated switchgear (GIS) in substations. However, since SF? has a high global warming potential (GWP), it is necessary to find an eco-friendly alternative insulation gas. In order to examine the possibility of using alternative insulation gases for SF? in power distribution system equipment, the dielectric strength and physical phenomena of dry air in a quasi-uniform electric field are investigated experimentally in this paper. As a result, the breakdown voltages for positive polarity are higher than those for negative polarity under impulse voltage applications. The negative 50[%] flashover voltage, V50 of dry air under conditions above 0.4[㎫] gas pressure, is higher than 150[㎸], that is the basic impulse insulation level of distribution equipment. The V50 increases linearly with increasing the gas pressure, regardless of the waveform and polarity of the applied impulse voltages. The voltage-time curves are dependent on the rise time of the impulse voltage and gas pressure. Furthermore, streamer discharge was observed through light emission images by an ICCD camera under impulse voltage applications. |