測量(liang)變壓器直流電(dian)阻的方法

測(ce)量方法

1、電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)-電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)法(fa) 原理(li)(li)是在(zai)被(bei)測(ce)(ce)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)中(zhong)通(tong)適(shi)當的(de)(de)(de)(de)(de)(de)直流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)，然(ran)(ran)后(hou)測(ce)(ce)量(liang)(liang)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)中(zhong)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)和(he)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)兩(liang)端的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降，然(ran)(ran)后(hou)根(gen)據歐(ou)姆值(zhi)計(ji)算繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)直流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。法(fa)律(lv)。測(ce)(ce)量(liang)(liang)時(shi)(shi)(shi)，所用儀(yi)表(biao)應(ying)(ying)(ying)不(bu)小(xiao)(xiao)于(yu)(yu)0.5，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)表(biao)應(ying)(ying)(ying)選(xuan)用內(nei)(nei)阻(zu)(zu)較(jiao)(jiao)(jiao)小(xiao)(xiao)的(de)(de)(de)(de)(de)(de)，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)應(ying)(ying)(ying)選(xuan)用內(nei)(nei)阻(zu)(zu)較(jiao)(jiao)(jiao)大(da)(da)的(de)(de)(de)(de)(de)(de)，引(yin)線(xian)要(yao)有(you)測(ce)(ce)量(liang)(liang)方法(fa) 1.電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)的(de)(de)(de)(de)(de)(de)原理(li)(li)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)法(fa)是在(zai)被(bei)測(ce)(ce)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)中(zhong)，通(tong)過(guo)(guo)(guo)適(shi)當的(de)(de)(de)(de)(de)(de)直流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)，測(ce)(ce)量(liang)(liang)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)中(zhong)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)和(he)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)兩(liang)端的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)降，然(ran)(ran)后(hou)根(gen)據歐(ou)姆定(ding)(ding)律(lv)計(ji)算繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)直流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。測(ce)(ce)量(liang)(liang)時(shi)(shi)(shi)，所用儀(yi)器(qi)應(ying)(ying)(ying)不(bu)小(xiao)(xiao)于(yu)(yu)0.5，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)表(biao)應(ying)(ying)(ying)選(xuan)擇內(nei)(nei)阻(zu)(zu)較(jiao)(jiao)(jiao)小(xiao)(xiao)的(de)(de)(de)(de)(de)(de)，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)應(ying)(ying)(ying)選(xuan)擇內(nei)(nei)阻(zu)(zu)較(jiao)(jiao)(jiao)大(da)(da)的(de)(de)(de)(de)(de)(de)，引(yin)線(xian)應(ying)(ying)(ying)有(you)足(zu)夠(gou)的(de)(de)(de)(de)(de)(de)橫截面(mian)。測(ce)(ce)量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)感較(jiao)(jiao)(jiao)大(da)(da)的(de)(de)(de)(de)(de)(de)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)時(shi)(shi)(shi)，也需(xu)(xu)要(yao)足(zu)夠(gou)的(de)(de)(de)(de)(de)(de)充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)間(jian)(jian)。通(tong)過(guo)(guo)(guo)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)應(ying)(ying)(ying)限制(zhi)在(zai)繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)額(e)定(ding)(ding)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)的(de)(de)(de)(de)(de)(de) 20% 以下。這種方法(fa)的(de)(de)(de)(de)(de)(de)主要(yao)缺點是需(xu)(xu)要(yao)很(hen)(hen)長時(shi)(shi)(shi)間(jian)(jian)才(cai)能(neng)測(ce)(ce)量(liang)(liang)出準確(que)的(de)(de)(de)(de)(de)(de)值(zhi)。因為(wei)每一(yi)相繞(rao)(rao)(rao)組(zu)(zu)(zu)(zu)可以等效為(wei)一(yi)個電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)感的(de)(de)(de)(de)(de)(de)串聯電(dian)(dian)(dian)(dian)(dian)(dian)路，所以在(zai)接通(tong)電(dian)(dian)(dian)(dian)(dian)(dian)源后(hou)，電(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)的(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)從零逐(zhu)漸增(zeng)加到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)，然(ran)(ran)后(hou)逐(zhu)漸減(jian)小(xiao)(xiao)到(dao)穩態值(zhi)。需(xu)(xu)要(yao)一(yi)個過(guo)(guo)(guo)渡(du)過(guo)(guo)(guo)程，過(guo)(guo)(guo)渡(du)時(shi)(shi)(shi)間(jian)(jian)的(de)(de)(de)(de)(de)(de)長短取決于(yu)(yu)電(dian)(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)(jian)常(chang)數 tu003dL/R。由于(yu)(yu)變壓(ya)(ya)器(qi)鐵芯的(de)(de)(de)(de)(de)(de)磁導率很(hen)(hen)高，L的(de)(de)(de)(de)(de)(de)值(zhi)大(da)(da)大(da)(da)增(zeng)加，而(er)線(xian)圈的(de)(de)(de)(de)(de)(de)直流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值(zhi)很(hen)(hen)小(xiao)(xiao)，所以時(shi)(shi)(shi)間(jian)(jian)常(chang)數t的(de)(de)(de)(de)(de)(de)值(zhi)很(hen)(hen)大(da)(da)。一(yi)般來(lai)(lai)說，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)表(biao)和(he)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)表(biao)的(de)(de)(de)(de)(de)(de)內(nei)(nei)阻(zu)(zu)對(dui)測(ce)(ce)量(liang)(liang)結果(guo)有(you)一(yi)定(ding)(ding)的(de)(de)(de)(de)(de)(de)影響(xiang)，電(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)經過(guo)(guo)(guo)大(da)(da)約(yue)Tu003d3到(dao)5倍時(shi)(shi)(shi)間(jian)(jian)常(chang)數的(de)(de)(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)(jian)后(hou)才(cai)能(neng)達(da)到(dao)穩態值(zhi)，也就是需(xu)(xu)要(yao)幾十分鐘甚至(zhi)更長的(de)(de)(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)(jian)來(lai)(lai)測(ce)(ce)量(liang)(liang)直流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)的(de)(de)(de)(de)(de)(de)準確(que)值(zhi)。

2、平衡(heng)電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)法 平衡(heng)電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)法是利用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)平衡(heng)原理來測(ce)量(liang)直(zhi)流電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。常用(yong)(yong)(yong)的(de)平衡(heng)電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)法有兩種：單臂(bei)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)或雙臂(bei)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)。這種方法可以(yi)直(zhi)接讀取數(shu)據，準確率很高。在(zai)中(zhong)小型變壓器的(de)實際測(ce)量(liang)中(zhong)，多采用(yong)(yong)(yong)直(zhi)流電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)法。當被測(ce)線圈(quan)的(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值在(zai)1Ω以(yi)上時，一般用(yong)(yong)(yong)單臂(bei)電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)測(ce)量(liang)，1Ω以(yi)下(xia)用(yong)(yong)(yong)雙臂(bei)電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)測(ce)量(liang)。使用(yong)(yong)(yong)雙臂(bei)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)接線時，橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)的(de)電(dian)(dian)(dian)(dian)(dian)位樁(zhuang)頭(tou)應靠(kao)近(jin)待(dai)測(ce)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)，電(dian)(dian)(dian)(dian)(dian)流樁(zhuang)頭(tou)應接電(dian)(dian)(dian)(dian)(dian)位樁(zhuang)頭(tou)。測(ce)量(liang)前先估算被測(ce)線圈(quan)的(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值，將電(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)(qiao)(qiao)(qiao)(qiao)放(fang)大旋鈕調(diao)到(dao)合適位置，將未測(ce)線圈(quan)短接接地(di)，然后打開(kai)電(dian)(dian)(dian)(dian)(dian)源開(kai)關充電(dian)(dian)(dian)(dian)(dian)，待(dai)測(ce)完(wan)后按(an)下(xia)振(zhen)(zhen)鏡開(kai)關它已充滿電(dian)(dian)(dian)(dian)(dian)。調(diao)整(zheng)測(ce)量(liang)臂(bei)使振(zhen)(zhen)鏡指針移動到(dao)振(zhen)(zhen)鏡刻(ke)度(du)中(zhong)間的(de)零(ling)線上，并進(jin)行微(wei)調(diao)。當指針停在(zai)零(ling)位時，記錄電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值。此時，被測(ce)線圈(quan)的(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值u003d為(wei)放(fang)大倍數(shu)×測(ce)量(liang)臂(bei)電(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值。測(ce)量(liang)完(wan)成后，先松開(kai)振(zhen)(zhen)鏡按(an)鈕，再松開(kai)電(dian)(dian)(dian)(dian)(dian)源開(kai)關。

3、三(san)相(xiang)(xiang)(xiang)繞組(zu)(zu)同(tong)(tong)時加(jia)(jia)(jia)壓(ya)法(fa) 三(san)相(xiang)(xiang)(xiang)繞組(zu)(zu)同(tong)(tong)時加(jia)(jia)(jia)電(dian)(dian)(dian)(dian)壓(ya)測量(liang)變(bian)壓(ya)器的(de)(de)(de)(de)(de)(de)(de)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻(zu)。根據(ju)楞次定律(lv)，各(ge)(ge)相(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)產(chan)生(sheng)的(de)(de)(de)(de)(de)(de)(de)磁(ci)(ci)(ci)通在鐵(tie)芯中(zhong)相(xiang)(xiang)(xiang)互(hu)抵消，合成磁(ci)(ci)(ci)通為(wei)零。減(jian)小(xiao)電(dian)(dian)(dian)(dian)感L的(de)(de)(de)(de)(de)(de)(de)值減(jian)小(xiao)了電(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)(de)(de)(de)時間(jian)(jian)(jian)常數(shu)，即(ji)減(jian)少了測量(liang)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻(zu)的(de)(de)(de)(de)(de)(de)(de)時間(jian)(jian)(jian)，提高了工作(zuo)(zuo)效率。在測量(liang)中(zhong)，還應(ying)考慮繞組(zu)(zu)電(dian)(dian)(dian)(dian)阻(zu)的(de)(de)(de)(de)(de)(de)(de)溫度影響因素(su)和直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻(zu)的(de)(de)(de)(de)(de)(de)(de)不平衡率等(deng)因素(su)。用電(dian)(dian)(dian)(dian)壓(ya)降(jiang)法(fa)測量(liang)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻(zu)需要很長(chang)時間(jian)(jian)(jian)才能得(de)(de)到(dao)準確的(de)(de)(de)(de)(de)(de)(de)值，主要是(shi)(shi)因為(wei)線圈中(zhong)流(liu)(liu)(liu)(liu)(liu)(liu)動的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)在變(bian)化(hua)過(guo)(guo)程(cheng)中(zhong)會在高導(dao)磁(ci)(ci)(ci)率鐵(tie)芯中(zhong)產(chan)生(sheng)磁(ci)(ci)(ci)通量(liang)，導(dao)致L增大(da)。如(ru)果磁(ci)(ci)(ci)通量(liang)減(jian)小(xiao)，L 的(de)(de)(de)(de)(de)(de)(de)值也(ye)(ye)會減(jian)小(xiao)，電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)變(bian)化(hua)的(de)(de)(de)(de)(de)(de)(de)時間(jian)(jian)(jian)（取(qu)決于時間(jian)(jian)(jian)常數(shu)）也(ye)(ye)會減(jian)小(xiao)。這可(ke)以通過(guo)(guo)同(tong)(tong)時向(xiang)變(bian)壓(ya)器的(de)(de)(de)(de)(de)(de)(de)三(san)相(xiang)(xiang)(xiang)繞組(zu)(zu)施加(jia)(jia)(jia)電(dian)(dian)(dian)(dian)壓(ya)并同(tong)(tong)時測量(liang)各(ge)(ge)相(xiang)(xiang)(xiang)的(de)(de)(de)(de)(de)(de)(de)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻(zu)來實現。當電(dian)(dian)(dian)(dian)壓(ya)同(tong)(tong)時加(jia)(jia)(jia)在三(san)相(xiang)(xiang)(xiang)繞組(zu)(zu)上(shang)(shang)時，各(ge)(ge)相(xiang)(xiang)(xiang)繞組(zu)(zu)中(zhong)的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)從零開始增加(jia)(jia)(jia)。根據(ju)右手螺旋定則，三(san)相(xiang)(xiang)(xiang)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)在每個鐵(tie)芯腿(tui)上(shang)(shang)產(chan)生(sheng)不同(tong)(tong)的(de)(de)(de)(de)(de)(de)(de)磁(ci)(ci)(ci)通方向(xiang)，它們的(de)(de)(de)(de)(de)(de)(de)作(zuo)(zuo)用是(shi)(shi)互(hu)斥(chi)的(de)(de)(de)(de)(de)(de)(de)。取(qu)消，結果是(shi)(shi)鐵(tie)芯中(zhong)的(de)(de)(de)(de)(de)(de)(de)合成磁(ci)(ci)(ci)通量(liang)大(da)約為(wei)零。這大(da)大(da)降(jiang)低(di)了電(dian)(dian)(dian)(dian)感值L，所以時間(jian)(jian)(jian)常數(shu)t也(ye)(ye)最小(xiao)化(hua)，測試過(guo)(guo)程(cheng)中(zhong)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)變(bian)化(hua)的(de)(de)(de)(de)(de)(de)(de)瞬態過(guo)(guo)程(cheng)也(ye)(ye)大(da)大(da)縮短，可(ke)以在短時間(jian)(jian)(jian)內得(de)(de)到(dao)穩定的(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)值，就可(ke)以得(de)(de)到(dao)繞組(zu)(zu)的(de)(de)(de)(de)(de)(de)(de)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)阻(zu)值。

測量目的

1、檢查(cha)導電回路(lu)是否有短(duan)路(lu)、斷路(lu)或接線錯誤；

2、檢(jian)查繞組線的(de)(de)焊接(jie)(jie)點、引線與套管(guan)的(de)(de)連接(jie)(jie)是(shi)否良好、分(fen)接(jie)(jie)開關是(shi)否接(jie)(jie)觸不(bu)良等。

3、還可檢查繞組(zu)所用(yong)的線材(cai)規格是否符合(he)設計(ji)要求。