直流(liu)電(dian)阻測(ce)試(shi)儀(yi)操作時(shi)應(ying)該註意(yi)的幾(ji)個(ge)要(yao)點(dian)
直流(liu)電(dian)阻測(ce)試(shi)儀(yi)在測(ce)量過(guo)程中,除(chu)要(yao)嚴(yan)格遵守電(dian)氣安全規(gui)程和設(she)備(bei)試驗規(gui)程外,還(hai)要(yao)特別註意(yi),在線(xian)圈溫(wen)度(du)穩(wen)定的情(qing)況(kuang)下進行(xing)測量(liang),要(yao)求(qiu)變壓器油箱上(shang)、下(xia)部(bu)的溫(wen)度(du)之(zhi)差(cha)不(bu)超(chao)過(guo)3℃。由於(yu)變壓器線(xian)圈存(cun)有電(dian)感,測(ce)量(liang)時(shi)的充(chong)電(dian)電(dian)流(liu)不(bu)太穩(wen)定,壹(yi)定要(yao)在(zai)電(dian)流(liu)穩(wen)定後(hou)再(zai)計(ji)數,必(bi)要(yao)時(shi)需采取(qu)縮(suo)短充(chong)電(dian)時(shi)間(jian)的措(cuo)施。盡(jin)量減(jian)少(shao)試(shi)驗回(hui)路(lu)中(zhong)的導(dao)線(xian)接觸電(dian)阻,運(yun)行中(zhong)的變壓器分接頭常受(shou)油膜(mo)等(deng)汙物的影(ying)響使其(qi)接觸不(bu)良,壹(yi)般需切(qie)換數次(ci)後(hou)再(zai)測(ce)量(liang),以(yi)免(mian)造成(cheng)判別錯誤(wu)。測量變壓器低(di)壓(ya)側(ce)時(shi),所有(you)人員(yuan)應與(yu)高(gao)壓(ya)側(ce)保持(chi)適當(dang)安(an)全距離。
直流(liu)電(dian)阻測(ce)試(shi)儀(yi)在運(yun)輸、儲(chu)存及(ji)工(gong)作中應避(bi)免(mian)強烈震(zhen)動、陽(yang)光(guang)直射和(he)磁(ci)場的影(ying)響,存放(fang)保管儀(yi)器時(shi),應(ying)註意(yi)環(huan)境溫(wen)度(du)和濕(shi)度(du),應放(fang)在(zai)幹燥、通風、無腐蝕氣體的地方為(wei)宜,不(bu)得(de)受(shou)潮(chao)、雨淋、暴(bao)曬,使用時(shi)輕(qing)拿、輕放(fang),不(bu)得(de)跌落。可(ke)以(yi)檢(jian)查(zha)出(chu)設(she)備(bei)的導(dao)電(dian)回(hui)路(lu)有(you)無接觸不(bu)良、焊(han)接不(bu)良、線(xian)圈故(gu)障及(ji)接線(xian)錯誤(wu)等缺陷(xian)。在(zai)中(zhong)、小型(xing)變壓器的實(shi)際(ji)測量中,大(da)多采用直流(liu)電(dian)橋法(fa),當被(bei)試(shi)線(xian)圈的電(dian)阻值(zhi)在(zai)1歐(ou)以(yi)上(shang)的壹(yi)般用單(dan)臂(bi)電(dian)橋測(ce)量,1歐(ou)以(yi)下(xia)的則(ze)用雙(shuang)臂(bi)電(dian)橋測(ce)量。在(zai)使用雙(shuang)臂(bi)電(dian)橋接線(xian)時(shi),電(dian)橋的電(dian)位樁(zhuang)頭要(yao)靠(kao)近被測(ce)電(dian)阻,電(dian)流(liu)樁頭要(yao)接在(zai)電(dian)位樁(zhuang)頭的上(shang)面。
直流(liu)電(dian)阻測(ce)試(shi)儀(yi)測量(liang)前,應(ying)先估計被測(ce)線(xian)圈的電(dian)阻值(zhi),將(jiang)電(dian)橋倍(bei)率(lv)選(xuan)鈕(niu)置(zhi)於適當(dang)位(wei)置,將(jiang)非被(bei)測(ce)線(xian)圈短路(lu)並(bing)接地,然後(hou)打(da)開(kai)電(dian)源開(kai)關充(chong)電(dian),待充(chong)足(zu)電(dian)後(hou)按(an)下(xia)檢(jian)流(liu)計開(kai)關,迅速調(tiao)節(jie)測量(liang)臂,使檢(jian)流(liu)計指(zhi)針(zhen)向檢(jian)流(liu)計刻度(du)中間(jian)的零位線(xian)方向移動,進(jin)行(xing)微調(tiao),待指針(zhen)平穩(wen)停(ting)在(zai)零位上(shang)時(shi)記錄電(dian)阻值(zhi),此(ci)時(shi),被(bei)測線(xian)圈電(dian)阻值(zhi)=倍(bei)率(lv)數×測(ce)量(liang)臂電(dian)阻值(zhi)。測(ce)量(liang)完畢(bi),先開(kai)放(fang)檢(jian)流(liu)計按(an)鈕(niu),再(zai)放(fang)開(kai)電(dian)源開(kai)關。
直流(liu)電(dian)阻測(ce)試(shi)儀(yi)測量(liang)前,應(ying)先估計被測(ce)線(xian)圈的電(dian)阻值(zhi),將(jiang)電(dian)橋倍(bei)率(lv)選(xuan)鈕(niu)置(zhi)於適當(dang)位(wei)置,將(jiang)非被(bei)測(ce)線(xian)圈短路(lu)並(bing)接地,然後(hou)打(da)開(kai)電(dian)源開(kai)關充(chong)電(dian),待充(chong)足(zu)電(dian)後(hou)按(an)下(xia)檢(jian)流(liu)計開(kai)關,迅速調(tiao)節(jie)測量(liang)臂,使檢(jian)流(liu)計指(zhi)針(zhen)向檢(jian)流(liu)計刻度(du)中間(jian)的零位線(xian)方向移動,進(jin)行(xing)微調(tiao),待指針(zhen)平穩(wen)停(ting)在(zai)零位上(shang)時(shi)記錄電(dian)阻值(zhi),此(ci)時(shi),被(bei)測線(xian)圈電(dian)阻值(zhi)=倍(bei)率(lv)數×測(ce)量(liang)臂電(dian)阻值(zhi)。測(ce)量(liang)完畢(bi),先開(kai)放(fang)檢(jian)流(liu)計按(an)鈕(niu),再(zai)放(fang)開(kai)電(dian)源開(kai)關。