電(dian)(dian)橋(qiao)法首先在(zai)電(dian)(dian)纜(lan)終(zhong)端處對電(dian)(dian)纜(lan)的(de)故(gu)障相(xiang)與(yu)非(fei)故(gu)障相(xiang)短接(jie)(jie),然后(hou)(hou)用單臂(bei)電(dian)(dian)橋(qiao)在(zai)電(dian)(dian)纜(lan)始(shi)端對故(gu)障相(xiang)與(yu)被短接(jie)(jie)的(de)非(fei)故(gu)障相(xiang)進行連接(jie)(jie),*后(hou)(hou)測量非(fei)故(gu)障相(xiang)電(dian)(dian)阻(zu)與(yu)故(gu)障相(xiang)故(gu)障點之后(hou)(hou)的(de)電(dian)(dian)阻(zu),并(bing)相(xiang)加兩(liang)者用它們的(de)和來比故(gu)障相(xiang)故(gu)障點之前電(dian)(dian)阻(zu),綜合考(kao)慮電(dian)(dian)纜(lan)長度(du),就可把電(dian)(dian)纜(lan)故(gu)障點的(de)詳(xiang)細(xi)位置計算出來。
簡(jian)單、方便、高精確度是(shi)電(dian)橋法的主要優點(dian),電(dian)橋法的缺點(dian)是(shi)在檢(jian)(jian)測(ce)高阻(zu)故障(zhang)與(yu)閃絡(luo)性(xing)故障(zhang)時(shi)(shi),電(dian)橋法不適(shi)用(yong),這主要是(shi)由于當(dang)故障(zhang)電(dian)阻(zu)很高時(shi)(shi),電(dian)橋電(dian)流(liu)通常都比(bi)較小(xiao),探測(ce)比(bi)較困難。另外,應用(yong)電(dian)橋法進行(xing)檢(jian)(jian)測(ce)作業時(shi)(shi),應事先知(zhi)道電(dian)纜長度,當(dang)遇到(dao)組成電(dian)纜線路的各電(dian)纜截面(mian)不同(tong)時(shi)(shi),應先進行(xing)換算(suan),然后(hou)再(zai)進行(xing)檢(jian)(jian)測(ce)。
低壓(ya)脈(mo)(mo)沖(chong)(chong)反射(she)(she)法在電(dian)纜(lan)故(gu)障(zhang)中注入低壓(ya)脈(mo)(mo)沖(chong)(chong),基于故(gu)障(zhang)點的阻(zu)抗與其他點不(bu)匹配,低壓(ya)脈(mo)(mo)沖(chong)(chong)在電(dian)纜(lan)中傳播遇到(dao)故(gu)障(zhang)點時,會(hui)有反射(she)(she)脈(mo)(mo)沖(chong)(chong)出現,依據發射(she)(she)脈(mo)(mo)沖(chong)(chong)與反射(she)(she)脈(mo)(mo)沖(chong)(chong)實際(ji)(ji)存(cun)在的往返時間差大小(xiao)與脈(mo)(mo)沖(chong)(chong)具(ju)(ju)體傳播速度,便可把故(gu)障(zhang)點的位置(zhi)計(ji)算出來。由于測(ce)(ce)(ce)量(liang)電(dian)纜(lan)故(gu)障(zhang)的儀器通(tong)常都是使用矩形脈(mo)(mo)沖(chong)(chong),而(er)矩形脈(mo)(mo)沖(chong)(chong)很容易形成,若在實際(ji)(ji)測(ce)(ce)(ce)量(liang)中,所得的反射(she)(she)脈(mo)(mo)沖(chong)(chong)重疊于發射(she)(she)脈(mo)(mo)沖(chong)(chong),這樣(yang)區(qu)分就(jiu)會(hui)很困難,故(gu)障(zhang)點的具(ju)(ju)體距(ju)離也(ye)就(jiu)不(bu)能(neng)測(ce)(ce)(ce)出,可以說這種檢(jian)測(ce)(ce)(ce)法具(ju)(ju)有一定檢(jian)測(ce)(ce)(ce)盲區(qu)。
沖擊(ji)高壓(ya)(ya)閃絡法在對(dui)電(dian)纜故(gu)障(zhang)進行(xing)(xing)檢測(ce)的(de)(de)(de)(de)一(yi)些方法當中,施工(gong)人員應用十(shi)分(fen)廣泛的(de)(de)(de)(de)一(yi)種方法是沖擊(ji)高壓(ya)(ya)閃絡法。這 種方法的(de)(de)(de)(de)檢測(ce)原(yuan)理是在故(gu)障(zhang)電(dian)纜的(de)(de)(de)(de)開(kai)端(duan)地(di)方施 加沖擊(ji)高壓(ya)(ya),從而(er)對(dui)發生(sheng)故(gu) 障(zhang)的(de)(de)(de)(de)地(di)方進行(xing)(xing)十(shi)分(fen)迅速(su)的(de)(de)(de)(de)擊(ji)穿,以及記錄下(xia)故(gu) 障(zhang)地(di)方一(yi)剎那電(dian)壓(ya)(ya)突跳的(de)(de)(de)(de)數據信息。在仔細研究電(dian)纜故(gu)障(zhang)地(di)方與電(dian)纜始末(mo)數 據信息耗費時(shi)間的(de)(de)(de)(de)基礎上(shang)對(dui)時(shi)間距離進行(xing)(xing)測(ce)試,從而(er)得到故(gu)障(zhang)的(de)(de)(de)(de)地(di)方,以及執行(xing)(xing)解(jie)決對(dui)策。?
二(er)次(ci)脈(mo)沖(chong)法對(dui)于二(er)次(ci)脈(mo)沖(chong)法來(lai)講(jiang),其(qi)是有效應(ying)用形(xing)(xing)成(cheng)(cheng)一(yi)(yi)體化高壓(ya)發生器(qi)一(yi)(yi)剎那的(de)沖(chong)擊(ji)高壓(ya)脈(mo)沖(chong)以(yi)(yi)(yi)(yi)及(ji)向電(dian)(dian)纜(lan)故(gu)(gu)障(zhang)地方(fang)引送,在(zai)(zai)對(dui)故(gu)(gu)障(zhang)地方(fang)有效刺穿(chuan)的(de)前提(ti)條件下(xia),延長擊(ji)穿(chuan)后(hou)故(gu)(gu)障(zhang)地方(fang)形(xing)(xing)成(cheng)(cheng)電(dian)(dian)弧的(de)不間(jian)斷時間(jian)。當然,需要(yao)清楚的(de)是,在(zai)(zai)同一(yi)(yi)時間(jian),一(yi)(yi)個(ge)(ge)(ge)(ge)觸(chu)發脈(mo)沖(chong)可以(yi)(yi)(yi)(yi)對(dui)二(er)次(ci)脈(mo)沖(chong)自動(dong)觸(chu) 發裝(zhuang)置(zhi)(zhi)以(yi)(yi)(yi)(yi)及(ji)電(dian)(dian)纜(lan)檢測儀器(qi)的(de)運行(xing)(xing)進(jin)(jin)行(xing)(xing)觸(chu)發,這樣對(dui)二(er)次(ci)脈(mo)沖(chong)自動(dong)觸(chu)發裝(zhuang)置(zhi)(zhi)進(jin)(jin)行(xing)(xing)啟動(dong)的(de)基礎 上(shang) 發射出兩個(ge)(ge)(ge)(ge)低 壓(ya) 脈(mo)沖(chong),通過形(xing)(xing)成(cheng)(cheng)二(er)次(ci) 脈(mo)沖(chong)的(de)裝(zhuang)置(zhi)(zhi)后(hou)在(zai)(zai)檢測故(gu)(gu)障(zhang)電(dian)(dian)纜(lan)上(shang)進(jin)(jin)行(xing)(xing)有效傳輸,從而對(dui)電(dian)(dian)纜(lan)進(jin)(jin)行(xing)(xing)擊(ji)穿(chuan)。通過檢測儀器(qi)來(lai)查(cha)看(kan)電(dian)(dian)壓(ya)波(bo)形(xing)(xing)浮動(dong)的(de)特點和形(xing)(xing)成(cheng)(cheng)電(dian)(dian)弧整個(ge)(ge)(ge)(ge)過程的(de)反射波(bo)長,全面和系統記錄在(zai)(zai)檢測裝(zhuang)置(zhi)(zhi)的(de)屏幕上(shang),以(yi)(yi)(yi)(yi)及(ji)區別(bie)一(yi)(yi)系列種(zhong)類的(de)電(dian)(dian)流波(bo)動(dong),其(qi)中,一(yi)(yi)個(ge)(ge)(ge)(ge)對(dui)電(dian)(dian)纜(lan)的(de)實(shi)際(ji)長度進(jin)(jin)行(xing)(xing)體現;另一(yi)(yi)個(ge)(ge)(ge)(ge)對(dui)短路電(dian)(dian)纜(lan)故(gu)(gu)障(zhang)的(de)實(shi)際(ji)距離(li)進(jin)(jin)行(xing)(xing)體現。