준평등전계에서 SF6/CF4 혼합가스의 절연 파괴 전압 및 임계전계 특성

초록

SF6 is the most commonly used insulating gas in electrical systems. But In these days SF6 mixtures and alternative gas has been studied because of global warming. so although many studies have been carried out about binary gas mixtures with SF6, few studies were presented about breakdown characteristics of SF6/CF4 mixtures. At present study the breakdown characteristics of SF6/CF4 mixtures in quasi-uniform field was performed. This experiments were carried out under AC voltages. The rod-rod electrode was used with 5 mm gap distance. The mixture of SF6/CF4 containing 20%,50%,70% of SF6 were compared with pure SF6 and CF4 gas and gas pressure ranged from 0.1 to 0.5 MPa. The show that the breakdown voltages of gas were linearly increased according to the pressure in quasi-uniform field. For breakdown vlotage values of (E/P)crit are important. Because If values of (E/P) is a little more than (E/P)crit, electrons rapidly increase and streamer discharge gernerates. Through this experiments values of (E/P)crit are found to vary with the ratio of SF6/CF4 mixture according to the following relationship.