摘要
在中性点不接地(绝缘)和消弧线圈接地电力系统中,单相间歇性电弧接地有时会引发相间短路,过去将这类事故原因大多归结为绝缘弱或单相间歇性电弧接地过电压高。事实上,所有这类型事故均用这两个原因是解释不了的,也不全面。国内外实测"单相间歇性电弧接地过电压"为3～4倍相电压,正常绝缘水平是能耐受的。在分析事故时,提醒人们不要忘了早就实测证实的,在单相接地过渡阶段的高频振荡电流电弧效应。分析认为:"几百安培的高频振荡电流电弧效应"是引发烧毁电缆或室内配电装置的一个不可忽视的原因。
In the electric power system with the neutral point ungrounded or grounded through the arc suppression coil,the single phase intermittent electric arc grounding can sometimes induce short circuit between the phases.In the past the causes of such faults were ascribed to too weak insulation or too high overvoltage due to the single phase intermittent electric arc grounding.To say that all such kind of faults arises because of the above-mentioned two causes is inconvincible or not comprehensive enough.According to the tests conducted in our country or abroad the overvoltage produced by the single phase intermittent electric arc grounding amounts to 3~4 times of the phase voltage which is sustainable so far as normal insulation level is considered.During the process of fault analysis we should remind our colleagues not to forget that the electric arc effect caused by the high frequency oscillation during the transition period of the single phase grounding has already been verified by tests.According to the result of analysis the electric arc effect due to the high frequency oscillation current of several hundred amperes proves the main cause that will lead to the burning-out of the cables and the indoor distribution devices and can never be neglected.
出处
《上海电力》
2004年第3期212-215,共4页
Shanghai Electric Power
关键词
电力系统
单相接地
相间短路
消弧线圈
配电网
neutral point
single phase intermittent electric arc grounding
overvoltage
