3.1 電容放電沖擊法
變壓(ya)(ya)(ya)器(qi)(qi)鐵(tie)(tie)芯多(duo)點(dian)(dian)(dian)接(jie)地故(gu)(gu)(gu)(gu)障(zhang)(zhang)一(yi)般都是(shi)由鐵(tie)(tie)芯毛刺、焊渣或懸浮物引起的(de)(de)(de)(de)。可以利用(yong)(yong)高(gao)壓(ya)(ya)(ya)電(dian)(dian)氣(qi)試驗，然后用(yong)(yong)升(sheng)壓(ya)(ya)(ya)變壓(ya)(ya)(ya)器(qi)(qi)進行(xing)慢慢升(sheng)壓(ya)(ya)(ya)放(fang)電(dian)(dian)，但是(shi)在做(zuo)試驗的(de)(de)(de)(de)時候要根據現場的(de)(de)(de)(de)環境、變壓(ya)(ya)(ya)器(qi)(qi)的(de)(de)(de)(de)接(jie)地方式和(he)接(jie)地程度等具體情況來進行(xing)。具體的(de)(de)(de)(de)操作(zuo)步(bu)驟是(shi)：首先，要用(yong)(yong)輸出(chu)電(dian)(dian)壓(ya)(ya)(ya)大約在2500V 的(de)(de)(de)(de)直流電(dian)(dian)壓(ya)(ya)(ya)發生器(qi)(qi)對0.3 ～ 50μF 左右(you)的(de)(de)(de)(de)電(dian)(dian)容(rong)進行(xing)充電(dian)(dian)，再用(yong)(yong)充好電(dian)(dian)的(de)(de)(de)(de)電(dian)(dian)容(rong)器(qi)(qi)對變壓(ya)(ya)(ya)器(qi)(qi)鐵(tie)(tie)芯多(duo)點(dian)(dian)(dian)接(jie)地故(gu)(gu)(gu)(gu)障(zhang)(zhang)點(dian)(dian)(dian)進行(xing)放(fang)電(dian)(dian)，此時判定(ding)(ding)變壓(ya)(ya)(ya)器(qi)(qi)鐵(tie)(tie)芯多(duo)點(dian)(dian)(dian)接(jie)地故(gu)(gu)(gu)(gu)障(zhang)(zhang)點(dian)(dian)(dian)，就是(shi)聽深孔磨床有沒有響聲，看有沒有青煙(yan)冒出(chu)就可以判定(ding)(ding)。但這樣還不算(suan)完(wan)成(cheng)了電(dian)(dian)容(rong)放(fang)電(dian)(dian)沖擊(ji)，在判定(ding)(ding)了故(gu)(gu)(gu)(gu)障(zhang)(zhang)點(dian)(dian)(dian)以后還需要用(yong)(yong)絕緣拉(la)桿將電(dian)(dian)容(rong)器(qi)(qi)與(yu)(yu)直流電(dian)(dian)壓(ya)(ya)(ya)發生器(qi)(qi)的(de)(de)(de)(de)連接(jie)線(xian)斷開并與(yu)(yu)外引線(xian)接(jie)觸，然后能聽到(dao)放(fang)電(dian)(dian)聲時才算(suan)完(wan)成(cheng)。要證明(ming)已經排除變壓(ya)(ya)(ya)器(qi)(qi)鐵(tie)(tie)芯多(duo)點(dian)(dian)(dian)接(jie)地故(gu)(gu)(gu)(gu)障(zhang)(zhang)，需要用(yong)(yong)1000V 兆(zhao)歐表測量(liang)變壓(ya)(ya)(ya)器(qi)(qi)鐵(tie)(tie)芯絕緣電(dian)(dian)阻，絕緣電(dian)(dian)阻值(zhi)達到(dao)正常值(zhi)時就代(dai)表已經排除了。
3.2 電(dian)流沖擊法
首先要先把(ba)電(dian)焊機(ji)的(de)輸出(chu)電(dian)流(liu)調(diao)到小值，之后(hou)把(ba)變(bian)壓器(qi)鐵(tie)芯接地(di)端和電(dian)焊機(ji)接地(di)線連在(zai)一(yi)起，墊腳要用焊把(ba)快速(su)碰觸，這個時(shi)候要墊腳與鐵(tie)芯片會形成一(yi)個回路后(hou)，流(liu)過接地(di)故障點的(de)電(dian)流(liu)就會把(ba)故障點燒掉。在(zai)使用大電(dian)流(liu)沖擊(ji)法操作時(shi)，變(bian)壓器(qi)鐵(tie)芯墊腳的(de)地(di)方如(ru)果冒出(chu)黑煙，就代表沖擊(ji)電(dian)流(liu)值在(zai)不斷加
大。這(zhe)時就要立(li)刻把電焊機(ji)給關掉，然后檢查墊(dian)(dian)腳(jiao)墊(dian)(dian)塊木(mu)紋(wen)方向有(you)(you)沒有(you)(you)發(fa)黑或存有(you)(you)碳化物，如果(guo)有(you)(you)就要將所有(you)(you)發(fa)黑的木(mu)墊(dian)(dian)塊換成干燥的木(mu)墊(dian)(dian)塊以后，對地(di)與鐵芯進行(xing)絕(jue)緣測(ce)量(liang)。測(ce)量(liang)結果(guo)如果(guo)是正常的，這(zhe)就表明變壓器鐵芯多點接地(di)故障已(yi)經(jing)排除。
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