| At the beginning of transmitting electricity project, tripping caused by lighting striking is always a difficult problem to safe supply of power, accidents of electric wire netting take majority , with strike by lightning with trouble of transmission line of electricity proportion accounted for to trip relatively heavy trouble of transmission line of electricity, especially in the transmission line of electricity in the mountain area, the circuit trouble is caused by lightning striking and tripping basically, accidents caused by thunder account for 1/3 or more of circuit tripping accidents, so we can reduce the trouble of transmission line of electricity greatly by preventing tripping caused by lightning striking, and then reduce the emergence frequency of the accident in the electric wire netting. So seeking effective defending thunder and protective measure of circuit is always the projet which workers in power industry all over the world pay close attention to.Because of the randomness and complexity of the lightning activity, there is a great deal of unknown composition on understanding transmissionlines of lightning harm in the world at present. In addition, because of the limitation of the observing , and lightning strike is a kind of statistics little probability incident, we measure it inaccurately and it is difficult to get lightning parameter about transmission lines and even very difficult to distinguish accurate flashover style of lightning fault, such as that it is being back striking or detour lightning, So we can not be definitude in defending the thunder. We are efforts to study protection of transmission lines through making investigations and observing it in order to clarify its characteristic ,find out problem further, and make the pointed thunder measure.In order to do thunderstorm protection of circuit well, the law of thunderstorm damage of electric transmission line should be studied and the nature of thunderstorm damage should be analyzed firstly. In this way suitable measure to protect thunderstorm can be choosed. According to domestic and international research and operation experience, lightning strike bears alternatives and some line segments which are apt to be hit in the circuits are existent. This research mainly investigates the situation of electric transmission line by lightning strike in Liuzhou over the years and lightning current as well as topographical situation, the situation of ground lightning near the transmission line, grounding resistance of bar, the thunderstorm strike and lightning protection measures of transmission line are checked out by thunder orientation. Partial coupling ground wire oforiginal 110KV of Liuzhou twine bureau in 70's, enhancement of insulation, installing line arrester, effect of lightning protection by adding aerial earth wire with drain line attached in recent years are calculated, analyzed, summarized and the characters of thunderstorm strike in transmission line are comprehensive studied so as to find out the law of thunderstorm strike and pointed measures to protect lightning. It is true that how to reduce lightning strike is no doubt important, but the more important thing is how to prevent the permanent fault caused by lightning which will acause much harm to electric network. So the study of permanent fault caused by lightning strike, analyses of practice result are introduced in this paper and arranged in more preceding chapter.Through research, analysis and practice, some measures of preventing the fault of lightning strike have proposed, such as selecting glass insulator for use , examining zero according to cycle and improving examining out rate of null value , improving the ability of hot stability of lead ground lines and sheltering the electric arc to burn etc. Analysis results about the nature of lightning strike have drawn that to 110kV and 220kV circuit, in the mountain area, relying mainly on winding and hitting lightning strike, whose proportion is about 80-90%, in the plain, hills area, relying mainly on striking back lightning s... |
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