電力系統(tǒng)故障中英文資料外文翻譯文獻(xiàn)(完整版)
【正文】 reephase faults, like balanced threephase loads, may be handled on a lioneutral basis or on an equivalent singlephase basis. Problems may be solved either in terms of volts, amperes, and ohms. The handing of faults on singlephase lines is of course identical to the method of handing threephase faults on an equivalent singlephase basis. Faults may be classified as permanent or temporary. Permanent faults are those in which insulation failure or structure failure produces damage that makes operation of the equipment impossible and requires repairs to be made. Temporary faults are those which may be removed by deenergizing the equipment for a short period of time, short circuits on overhead lines frequently are of this nature. High winds may cause two or more conductions to swing together momentarily. During the short period of contact. An arc is formed which may continue as long as line remains energized. However, if automatic equipment can be brought into operation to service as soon as the are is extinguished. Arcs across insulators due to overvoltages from lighting or switching transients usually can be cleared by automatic circuitbreaker operation before significant structure damage occurs. Because of this characteristic of faults on lines, many panies operate following a procedure known as highspeed reclosing. On the occurrence of a fault, the line is promptly deenergized by opening the circuit breakers at each end of the line. The breakers remain open long enough for the arc to clear, and then reclose automatically. In many instances service is restored in a fraction of a second. Of course, if structure damage has occurred and the fault persists, it is necessary for the breakers to reopen and lock 畢業(yè)設(shè)計(jì) open. 電力系統(tǒng)故障 每年新設(shè) 計(jì)的電力設(shè)備都使系統(tǒng)的可靠性不斷提高，然而，設(shè)備的使用不當(dāng)以及一些偶然遇到的外在因素均會(huì)導(dǎo)致系統(tǒng)故障的發(fā)生。在允許的期限內(nèi)，最靠近故障處的電壓會(huì)變得很低，致使用電設(shè)備無法正常運(yùn)行。此時(shí)，供電雖然往往能維持，但電壓較低。 大部分架空明線是用裸導(dǎo)體假設(shè)的，又是由于風(fēng)、雨、雷、或大樹、起重機(jī)，飛機(jī)及支撐物的損壞等因素會(huì)使導(dǎo)線偶然碰到一起。同一繞組相鄰畢業(yè)設(shè)計(jì) 線圈之間由于絕緣問題造成的短路可能是由于突然遇到外加高壓電所致。 故障有永久性故障及暫時(shí)性故障之分。故障發(fā)生時(shí)，線路兩端的斷路器跳閘，電流即被切斷，經(jīng)過一定的時(shí)間間隔，待電弧熄滅后，斷路器又自動(dòng)進(jìn)行 再次合閘，大多數(shù)情況下，不到一秒種即可恢復(fù)正常供電。只要線路通電，此電弧會(huì)一直存在。同
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