測量變壓器直流電阻的方法

測量方(fang)法

1、電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)-電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)法 原理是(shi)(shi)在(zai)(zai)被測(ce)繞(rao)組(zu)(zu)中(zhong)(zhong)通(tong)(tong)適(shi)當的(de)(de)(de)(de)直(zhi)(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)，然(ran)后(hou)測(ce)量(liang)(liang)繞(rao)組(zu)(zu)中(zhong)(zhong)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)和(he)(he)繞(rao)組(zu)(zu)兩端的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)(jiang)，然(ran)后(hou)根(gen)據(ju)歐姆值(zhi)計算繞(rao)組(zu)(zu)的(de)(de)(de)(de)直(zhi)(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。法律。測(ce)量(liang)(liang)時(shi)(shi)(shi)，所(suo)用(yong)(yong)儀(yi)表(biao)(biao)(biao)應(ying)(ying)(ying)(ying)不小(xiao)(xiao)(xiao)于0.5，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)表(biao)(biao)(biao)應(ying)(ying)(ying)(ying)選用(yong)(yong)內阻(zu)(zu)較小(xiao)(xiao)(xiao)的(de)(de)(de)(de)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)應(ying)(ying)(ying)(ying)選用(yong)(yong)內阻(zu)(zu)較大的(de)(de)(de)(de)，引(yin)線(xian)要(yao)(yao)有測(ce)量(liang)(liang)方法 1.電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)的(de)(de)(de)(de)原理電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)法是(shi)(shi)在(zai)(zai)被測(ce)繞(rao)組(zu)(zu)中(zhong)(zhong)，通(tong)(tong)過適(shi)當的(de)(de)(de)(de)直(zhi)(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)，測(ce)量(liang)(liang)繞(rao)組(zu)(zu)中(zhong)(zhong)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)和(he)(he)繞(rao)組(zu)(zu)兩端的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)(jiang)，然(ran)后(hou)根(gen)據(ju)歐姆定律計算繞(rao)組(zu)(zu)的(de)(de)(de)(de)直(zhi)(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)。測(ce)量(liang)(liang)時(shi)(shi)(shi)，所(suo)用(yong)(yong)儀(yi)器應(ying)(ying)(ying)(ying)不小(xiao)(xiao)(xiao)于0.5，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)表(biao)(biao)(biao)應(ying)(ying)(ying)(ying)選擇內阻(zu)(zu)較小(xiao)(xiao)(xiao)的(de)(de)(de)(de)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)應(ying)(ying)(ying)(ying)選擇內阻(zu)(zu)較大的(de)(de)(de)(de)，引(yin)線(xian)應(ying)(ying)(ying)(ying)有足夠的(de)(de)(de)(de)橫截面。測(ce)量(liang)(liang)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感較大的(de)(de)(de)(de)繞(rao)組(zu)(zu)時(shi)(shi)(shi)，也(ye)需要(yao)(yao)足夠的(de)(de)(de)(de)充電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)時(shi)(shi)(shi)間(jian)。通(tong)(tong)過繞(rao)組(zu)(zu)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)應(ying)(ying)(ying)(ying)限制在(zai)(zai)繞(rao)組(zu)(zu)額定電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)的(de)(de)(de)(de) 20% 以(yi)下。這種方法的(de)(de)(de)(de)主要(yao)(yao)缺點(dian)是(shi)(shi)需要(yao)(yao)很長(chang)時(shi)(shi)(shi)間(jian)才(cai)能(neng)(neng)測(ce)量(liang)(liang)出準確(que)的(de)(de)(de)(de)值(zhi)。因(yin)為(wei)每一(yi)相繞(rao)組(zu)(zu)可以(yi)等效為(wei)一(yi)個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)和(he)(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感的(de)(de)(de)(de)串聯電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路，所(suo)以(yi)在(zai)(zai)接通(tong)(tong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源后(hou)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)感中(zhong)(zhong)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)從零逐漸增加(jia)到(dao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)源電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)，然(ran)后(hou)逐漸減小(xiao)(xiao)(xiao)到(dao)穩態值(zhi)。需要(yao)(yao)一(yi)個(ge)過渡過程，過渡時(shi)(shi)(shi)間(jian)的(de)(de)(de)(de)長(chang)短取決于電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)路的(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)常(chang)數 tu003dL/R。由于變(bian)壓(ya)器鐵(tie)芯的(de)(de)(de)(de)磁導(dao)率很高，L的(de)(de)(de)(de)值(zhi)大大增加(jia)，而線(xian)圈的(de)(de)(de)(de)直(zhi)(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)值(zhi)很小(xiao)(xiao)(xiao)，所(suo)以(yi)時(shi)(shi)(shi)間(jian)常(chang)數t的(de)(de)(de)(de)值(zhi)很大。一(yi)般(ban)來說(shuo)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)表(biao)(biao)(biao)和(he)(he)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)表(biao)(biao)(biao)的(de)(de)(de)(de)內阻(zu)(zu)對測(ce)量(liang)(liang)結果有一(yi)定的(de)(de)(de)(de)影響，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)經過大約Tu003d3到(dao)5倍時(shi)(shi)(shi)間(jian)常(chang)數的(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)后(hou)才(cai)能(neng)(neng)達到(dao)穩態值(zhi)，也(ye)就(jiu)是(shi)(shi)需要(yao)(yao)幾(ji)十分(fen)鐘甚至更長(chang)的(de)(de)(de)(de)時(shi)(shi)(shi)間(jian)來測(ce)量(liang)(liang)直(zhi)(zhi)流(liu)(liu)(liu)(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)的(de)(de)(de)(de)準確(que)值(zhi)。

2、平衡(heng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)法(fa) 平衡(heng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)法(fa)是(shi)利用(yong)(yong)(yong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)平衡(heng)原理來測(ce)(ce)量(liang)直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻。常用(yong)(yong)(yong)的(de)平衡(heng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)法(fa)有兩種：單臂(bei)(bei)(bei)(bei)橋(qiao)(qiao)或雙臂(bei)(bei)(bei)(bei)橋(qiao)(qiao)。這種方法(fa)可以(yi)(yi)直(zhi)接(jie)讀取數據，準確率(lv)很高。在中(zhong)小型變壓(ya)器的(de)實際測(ce)(ce)量(liang)中(zhong)，多采用(yong)(yong)(yong)直(zhi)流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)法(fa)。當(dang)被(bei)測(ce)(ce)線(xian)(xian)圈(quan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻值(zhi)在1Ω以(yi)(yi)上(shang)時(shi)，一般(ban)用(yong)(yong)(yong)單臂(bei)(bei)(bei)(bei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)測(ce)(ce)量(liang)，1Ω以(yi)(yi)下用(yong)(yong)(yong)雙臂(bei)(bei)(bei)(bei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)測(ce)(ce)量(liang)。使用(yong)(yong)(yong)雙臂(bei)(bei)(bei)(bei)橋(qiao)(qiao)接(jie)線(xian)(xian)時(shi)，橋(qiao)(qiao)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位樁頭應靠近待(dai)測(ce)(ce)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)樁頭應接(jie)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位樁頭。測(ce)(ce)量(liang)前先估(gu)算被(bei)測(ce)(ce)線(xian)(xian)圈(quan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻值(zhi)，將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)橋(qiao)(qiao)放大旋鈕(niu)調到合適位置，將未測(ce)(ce)線(xian)(xian)圈(quan)短接(jie)接(jie)地，然后打開(kai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)開(kai)關充(chong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)，待(dai)測(ce)(ce)完(wan)(wan)后按下振鏡(jing)開(kai)關它(ta)已(yi)充(chong)滿電(dian)(dian)(dian)(dian)(dian)(dian)(dian)。調整測(ce)(ce)量(liang)臂(bei)(bei)(bei)(bei)使振鏡(jing)指(zhi)針移動到振鏡(jing)刻度中(zhong)間的(de)零線(xian)(xian)上(shang)，并進行微調。當(dang)指(zhi)針停在零位時(shi)，記錄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻值(zhi)。此時(shi)，被(bei)測(ce)(ce)線(xian)(xian)圈(quan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻值(zhi)u003d為放大倍數×測(ce)(ce)量(liang)臂(bei)(bei)(bei)(bei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻值(zhi)。測(ce)(ce)量(liang)完(wan)(wan)成后，先松(song)開(kai)振鏡(jing)按鈕(niu)，再松(song)開(kai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源(yuan)開(kai)關。

3、三相(xiang)(xiang)繞(rao)(rao)組(zu)(zu)同(tong)(tong)時(shi)(shi)(shi)(shi)加(jia)壓(ya)(ya)法 三相(xiang)(xiang)繞(rao)(rao)組(zu)(zu)同(tong)(tong)時(shi)(shi)(shi)(shi)加(jia)電(dian)(dian)(dian)壓(ya)(ya)測(ce)量(liang)變(bian)壓(ya)(ya)器的(de)(de)(de)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)阻(zu)。根據楞次定律，各相(xiang)(xiang)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)產(chan)生(sheng)的(de)(de)(de)磁(ci)(ci)通(tong)(tong)在(zai)(zai)鐵(tie)芯(xin)中(zhong)相(xiang)(xiang)互(hu)抵(di)消，合成磁(ci)(ci)通(tong)(tong)為零。減(jian)小(xiao)(xiao)電(dian)(dian)(dian)感L的(de)(de)(de)值(zhi)減(jian)小(xiao)(xiao)了(le)電(dian)(dian)(dian)路的(de)(de)(de)時(shi)(shi)(shi)(shi)間(jian)常數(shu)(shu)，即(ji)減(jian)少(shao)了(le)測(ce)量(liang)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)阻(zu)的(de)(de)(de)時(shi)(shi)(shi)(shi)間(jian)，提(ti)高了(le)工作效率(lv)。在(zai)(zai)測(ce)量(liang)中(zhong)，還應考慮繞(rao)(rao)組(zu)(zu)電(dian)(dian)(dian)阻(zu)的(de)(de)(de)溫度(du)影(ying)響因素和直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)阻(zu)的(de)(de)(de)不平衡率(lv)等因素。用電(dian)(dian)(dian)壓(ya)(ya)降法測(ce)量(liang)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)阻(zu)需要很長(chang)時(shi)(shi)(shi)(shi)間(jian)才(cai)能(neng)得(de)到準確的(de)(de)(de)值(zhi)，主(zhu)要是(shi)因為線圈中(zhong)流(liu)(liu)(liu)(liu)(liu)(liu)動的(de)(de)(de)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)在(zai)(zai)變(bian)化(hua)(hua)過程(cheng)中(zhong)會(hui)在(zai)(zai)高導磁(ci)(ci)率(lv)鐵(tie)芯(xin)中(zhong)產(chan)生(sheng)磁(ci)(ci)通(tong)(tong)量(liang)，導致L增大(da)(da)。如果(guo)磁(ci)(ci)通(tong)(tong)量(liang)減(jian)小(xiao)(xiao)，L 的(de)(de)(de)值(zhi)也(ye)會(hui)減(jian)小(xiao)(xiao)，電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)變(bian)化(hua)(hua)的(de)(de)(de)時(shi)(shi)(shi)(shi)間(jian)（取(qu)決于(yu)時(shi)(shi)(shi)(shi)間(jian)常數(shu)(shu)）也(ye)會(hui)減(jian)小(xiao)(xiao)。這(zhe)(zhe)可以通(tong)(tong)過同(tong)(tong)時(shi)(shi)(shi)(shi)向(xiang)變(bian)壓(ya)(ya)器的(de)(de)(de)三相(xiang)(xiang)繞(rao)(rao)組(zu)(zu)施(shi)加(jia)電(dian)(dian)(dian)壓(ya)(ya)并(bing)同(tong)(tong)時(shi)(shi)(shi)(shi)測(ce)量(liang)各相(xiang)(xiang)的(de)(de)(de)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)阻(zu)來實現。當電(dian)(dian)(dian)壓(ya)(ya)同(tong)(tong)時(shi)(shi)(shi)(shi)加(jia)在(zai)(zai)三相(xiang)(xiang)繞(rao)(rao)組(zu)(zu)上時(shi)(shi)(shi)(shi)，各相(xiang)(xiang)繞(rao)(rao)組(zu)(zu)中(zhong)的(de)(de)(de)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)從零開始增加(jia)。根據右手螺旋定則，三相(xiang)(xiang)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)在(zai)(zai)每個鐵(tie)芯(xin)腿上產(chan)生(sheng)不同(tong)(tong)的(de)(de)(de)磁(ci)(ci)通(tong)(tong)方向(xiang)，它們的(de)(de)(de)作用是(shi)互(hu)斥(chi)的(de)(de)(de)。取(qu)消，結(jie)果(guo)是(shi)鐵(tie)芯(xin)中(zhong)的(de)(de)(de)合成磁(ci)(ci)通(tong)(tong)量(liang)大(da)(da)約為零。這(zhe)(zhe)大(da)(da)大(da)(da)降低了(le)電(dian)(dian)(dian)感值(zhi)L，所(suo)以時(shi)(shi)(shi)(shi)間(jian)常數(shu)(shu)t也(ye)最小(xiao)(xiao)化(hua)(hua)，測(ce)試過程(cheng)中(zhong)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)變(bian)化(hua)(hua)的(de)(de)(de)瞬態過程(cheng)也(ye)大(da)(da)大(da)(da)縮短，可以在(zai)(zai)短時(shi)(shi)(shi)(shi)間(jian)內得(de)到穩(wen)定的(de)(de)(de)電(dian)(dian)(dian)流(liu)(liu)(liu)(liu)(liu)(liu)值(zhi)，就(jiu)可以得(de)到繞(rao)(rao)組(zu)(zu)的(de)(de)(de)直(zhi)流(liu)(liu)(liu)(liu)(liu)(liu)電(dian)(dian)(dian)阻(zu)值(zhi)。

測(ce)量(liang)目的(de)

1、檢查導電回路(lu)是否有短路(lu)、斷路(lu)或(huo)接線錯誤；

2、檢查繞組線的焊接點、引線與套管的連接是(shi)否良好、分接開關是(shi)否接觸不良等。

3、還可檢查繞組(zu)所用(yong)的線材規(gui)格是(shi)否符合設計要(yao)求。