變(bian)(bian)(bian)配(pei)電運行中，變(bian)(bian)(bian)壓(ya)器必(bi)不可少，熟悉和掌握變(bian)(bian)(bian)壓(ya)器的基本常識(shi)是(shi)非常有必(bi)要(yao)的，變(bian)(bian)(bian)壓(ya)器的基本知識(shi)儲備是(shi)每(mei)一個電力人必(bi)備的技(ji)能！以下關于變(bian)(bian)(bian)壓(ya)器的十大(da)疑問及(ji)解(jie)答(da)將便于大(da)家(jia)補充了解(jie)。

1、什么叫變壓器？

在交流電(dian)(dian)路(lu)中，將電(dian)(dian)壓(ya)升高(gao)(gao)或降(jiang)低的(de)(de)(de)設(she)備叫變(bian)壓(ya)器(qi)，變(bian)壓(ya)器(qi)能把(ba)任一數值(zhi)的(de)(de)(de)電(dian)(dian)壓(ya)轉變(bian)成頻率相同(tong)的(de)(de)(de)我們所需的(de)(de)(de)電(dian)(dian)壓(ya)值(zhi)，以(yi)滿(man)足電(dian)(dian)能的(de)(de)(de)輸送(song)，分配和(he)使(shi)用(yong)要求。例如發電(dian)(dian)廠發出來的(de)(de)(de)電(dian)(dian)，電(dian)(dian)壓(ya)等(deng)級(ji)較(jiao)(jiao)低，必(bi)(bi)須把(ba)電(dian)(dian)壓(ya)升高(gao)(gao)才能輸送(song)到較(jiao)(jiao)遠的(de)(de)(de)用(yong)電(dian)(dian)區，用(yong)電(dian)(dian)區又必(bi)(bi)須通過降(jiang)壓(ya)變(bian)成適用(yong)的(de)(de)(de)電(dian)(dian)壓(ya)等(deng)級(ji)，供(gong)給動力設(she)備及日常用(yong)電(dian)(dian)設(she)備使(shi)用(yong)。

2、變壓器是怎樣變換電壓的？

變(bian)壓(ya)(ya)(ya)器是(shi)根據(ju)電(dian)(dian)磁(ci)感應制成(cheng)的(de)(de)(de)。它由(you)一個用(yong)硅(gui)鋼(gang)(gang)片(pian)(或矽(xi)鋼(gang)(gang)片(pian))疊成(cheng)的(de)(de)(de)鐵(tie)芯(xin)(xin)和繞(rao)在鐵(tie)芯(xin)(xin)上的(de)(de)(de)兩組線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)構成(cheng)，鐵(tie)芯(xin)(xin)與線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)間彼此相(xiang)互絕緣，沒有任何電(dian)(dian)的(de)(de)(de)聯系，如圖所示。我們將變(bian)壓(ya)(ya)(ya)器和電(dian)(dian)源一側連(lian)接的(de)(de)(de)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)叫(jiao)(jiao)初(chu)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)(或叫(jiao)(jiao)原(yuan)邊(bian))，把(ba)變(bian)壓(ya)(ya)(ya)器和用(yong)電(dian)(dian)設備連(lian)接的(de)(de)(de)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)叫(jiao)(jiao)作次(ci)(ci)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)(或副邊(bian))。當(dang)將變(bian)壓(ya)(ya)(ya)器的(de)(de)(de)初(chu)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)接到交(jiao)(jiao)流(liu)電(dian)(dian)源上時，鐵(tie)芯(xin)(xin)中就會(hui)產生(sheng)變(bian)化的(de)(de)(de)磁(ci)力線(xian)(xian)(xian)。由(you)于次(ci)(ci)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)繞(rao)在同一鐵(tie)芯(xin)(xin)上，磁(ci)力線(xian)(xian)(xian)切割(ge)次(ci)(ci)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)，次(ci)(ci)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)上必然(ran)產生(sheng)感應電(dian)(dian)動勢，使(shi)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)兩端出現(xian)電(dian)(dian)壓(ya)(ya)(ya)。因磁(ci)力線(xian)(xian)(xian)是(shi)交(jiao)(jiao)變(bian)的(de)(de)(de)，所以次(ci)(ci)級(ji)線(xian)(xian)(xian)圈(quan)(quan)(quan)(quan)的(de)(de)(de)電(dian)(dian)壓(ya)(ya)(ya)也是(shi)交(jiao)(jiao)變(bian)的(de)(de)(de)。而且頻(pin)率與電(dian)(dian)源頻(pin)率完(wan)全(quan)相(xiang)同。

經(jing)理論證實(shi)，變壓(ya)(ya)(ya)器初級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)與次級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)電(dian)壓(ya)(ya)(ya)比(bi)和初級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)與次級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)的匝數比(bi)值有關，可用(yong)下式表(biao)示：初級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)電(dian)壓(ya)(ya)(ya)/次級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)電(dian)壓(ya)(ya)(ya)=初級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)匝數/次級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)匝數 說(shuo)明(ming)匝數越(yue)多，電(dian)壓(ya)(ya)(ya)就(jiu)越(yue)高。因此可以看出，次級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)比(bi)初級(ji)(ji)線(xian)(xian)(xian)(xian)圈(quan)(quan)(quan)少，就(jiu)是(shi)降壓(ya)(ya)(ya)變壓(ya)(ya)(ya)器。相反則為(wei)升壓(ya)(ya)(ya)變壓(ya)(ya)(ya)器。

3、變壓器部件是由哪些部分組成的？

變(bian)壓器部件主要是由鐵芯、線圈組成，此外還有油(you)箱、油(you)枕、絕緣(yuan)套管及分接開頭等。

4、什么是變壓器的銘牌?銘牌上有哪些主要技術數據？

變(bian)(bian)壓器(qi)的銘牌標明(ming)該(gai)臺變(bian)(bian)壓器(qi)的性能、技術(shu)規格和使用(yong)場合，用(yong)來滿足用(yong)戶的選用(yong)，通常(chang)選用(yong)注意的主(zhu)要技術(shu)數據有：

(1)額(e)定容(rong)量(liang)的(de)千伏安數。即(ji)額(e)定狀態下變(bian)(bian)壓(ya)器的(de)輸(shu)出(chu)能(neng)力。如單相(xiang)變(bian)(bian)壓(ya)器額(e)定容(rong)量(liang)=U線×I線；三相(xiang)變(bian)(bian)壓(ya)器容(rong)量(liang)=U線×I線。

(2)額定電壓伏數。分別標明初級線圈的端電壓和次(ci)級線圈的端電壓(不(bu)接(jie)負(fu)載時)值。注意三相變壓器(qi)的端電壓指(zhi)線電壓U線值。

(3)額(e)定(ding)電(dian)流(liu)安培數。指在額(e)定(ding)容(rong)量和允許溫(wen)升條件下(xia)，初級(ji)(ji)線(xian)圈(quan)和次級(ji)(ji)線(xian)圈(quan)允許長期通過的線(xian)電(dian)流(liu)I線(xian)值(zhi)。

(4)電壓(ya)(ya)比(bi)。指(zhi)初(chu)級(ji)線圈額(e)定電壓(ya)(ya)與次級(ji)線圈額(e)定電壓(ya)(ya)之比(bi)。

(5)接(jie)線(xian)方式。單相(xiang)變(bian)壓(ya)器僅(jin)有(you)高低壓(ya)各一(yi)組線(xian)圈，只供給(gei)單相(xiang)使(shi)用(yong)，三相(xiang)變(bian)壓(ya)器則有(you)Y/△式。除以(yi)上技(ji)術數(shu)據外，還有(you)變(bian)壓(ya)器的額(e)定(ding)頻率、相(xiang)數(shu)、溫升、變(bian)壓(ya)器的阻抗百分比等。

5、變壓器在運行中應該做哪幾種測試？

為了保證變(bian)壓器能夠(gou)正(zheng)常運行，應經常進行下列幾項(xiang)測試(shi)；

(1)溫(wen)度(du)測試(shi)。變壓器運行狀態是不(bu)是正常，溫(wen)度(du)的高低是很(hen)重要(yao)的。規(gui)程規(gui)定上層(ceng)油溫(wen)不(bu)得超(chao)過85C(即(ji)溫(wen)升(sheng)55C)。一般變壓器都(dou)裝(zhuang)有專用溫(wen)度(du)測定裝(zhuang)置。

(2)負荷(he)測(ce)定(ding)(ding)。為(wei)了提高變(bian)壓器(qi)的利(li)用(yong)(yong)率，減少電能(neng)的損失(shi)，在(zai)變(bian)壓器(qi)運行中，必須測(ce)定(ding)(ding)變(bian)壓器(qi)真正能(neng)承擔的供(gong)電能(neng)力。測(ce)定(ding)(ding)工(gong)作通常(chang)在(zai)每一(yi)季節用(yong)(yong)電高峰時期進行，用(yong)(yong)鉗形(xing)電流表(biao)直接測(ce)定(ding)(ding)。電流值應為(wei)變(bian)壓器(qi)額(e)定(ding)(ding)電流的70～80%，超(chao)過時說(shuo)明過負荷(he)，應立即調整。

(3)電(dian)壓(ya)測定。規程要求(qiu)電(dian)壓(ya)變(bian)動范(fan)(fan)圍(wei)應在額定電(dian)壓(ya)±5%以(yi)內。如(ru)果超(chao)過這(zhe)一范(fan)(fan)圍(wei)，應采用(yong)分接(jie)頭進行調整，使(shi)電(dian)壓(ya)達到規定范(fan)(fan)圍(wei)。一般用(yong)電(dian)壓(ya)表(biao)分別測量次(ci)級線(xian)圈(quan)端電(dian)壓(ya)和(he)未端用(yong)戶的端電(dian)壓(ya)。

(4)絕緣電(dian)(dian)(dian)阻(zu)測(ce)(ce)定(ding)(ding)。為(wei)了(le)使變壓(ya)器始終處于正常運行狀態，必須進(jin)行絕緣電(dian)(dian)(dian)阻(zu)的測(ce)(ce)定(ding)(ding)，以防(fang)絕緣老化和發生事故。測(ce)(ce)定(ding)(ding)時應設法使變壓(ya)器停止(zhi)運行，利用(yong)搖(yao)表(biao)測(ce)(ce)定(ding)(ding)變壓(ya)器絕緣電(dian)(dian)(dian)阻(zu)值，要(yao)求所(suo)測(ce)(ce)電(dian)(dian)(dian)阻(zu)不低(di)于以前所(suo)測(ce)(ce)值的70%，選(xuan)用(yong)搖(yao)表(biao)時，低(di)壓(ya)線圈(quan)可采用(yong)500伏電(dian)(dian)(dian)壓(ya)等(deng)級的。

6、變壓器在運行中有哪些損失？怎樣減少損失？

變壓器運行中的(de)損失包括兩部(bu)分(fen)；(1)是由(you)鐵(tie)芯引起(qi)的(de)，當線圈(quan)通電(dian)后，由(you)于磁(ci)力線是交變的(de)，引起(qi)鐵(tie)芯中渦流和磁(ci)滯損耗(hao)，這種(zhong)(zhong)損耗(hao)統稱鐵(tie)損。(2)是線圈(quan)自身的(de)電(dian)阻引起(qi)的(de)，當變壓器初級線圈(quan)和次級線圈(quan)有電(dian)流通過時，就要產(chan)生電(dian)能(neng)損失，這種(zhong)(zhong)損失叫銅損。

鐵(tie)損(sun)與銅損(sun)的(de)和就是(shi)變(bian)壓(ya)器(qi)(qi)損(sun)失(shi)(shi)，這些(xie)損(sun)失(shi)(shi)與變(bian)壓(ya)器(qi)(qi)容(rong)量、電壓(ya)和設(she)備利(li)用率有關。因此，在選用變(bian)壓(ya)器(qi)(qi)時(shi)，應盡量使設(she)備容(rong)量和實際使用量一致，以提高設(she)備利(li)用率，注意不(bu)要使變(bian)壓(ya)器(qi)(qi)輕載運(yun)行。

7、如何保證變壓器有一個額定的電壓輸出？

電壓(ya)太高或過低都會影響變壓(ya)器的(de)正常工(gong)作(zuo)和使(shi)用壽命(ming)，所以必須(xu)調壓(ya)。調壓(ya)的(de)方(fang)法是在初級線圈中引出幾(ji)個抽頭，接(jie)在分(fen)接(jie)開頭上，分(fen)接(jie)開頭通過轉(zhuan)動觸(chu)頭來改變線圈的(de)匝(za)數。只要(yao)轉(zhuan)動分(fen)接(jie)開關的(de)位置，即可得到需要(yao)的(de)額定電壓(ya)值。要(yao)注意的(de)是，調壓(ya)通常應在切斷變壓(ya)器所接(jie)的(de)負載后進行。

8、為什么變壓器不能過負荷運行？

過(guo)(guo)負荷(he)(he)(he)運(yun)行(xing)是(shi)指變(bian)壓(ya)器(qi)運(yun)行(xing)時超過(guo)(guo)了銘牌上規定的(de)電(dian)流值。過(guo)(guo)負荷(he)(he)(he)分為(wei)正常(chang)過(guo)(guo)負荷(he)(he)(he)和事故過(guo)(guo)負荷(he)(he)(he)兩種，前者是(shi)指在正常(chang)供電(dian)情況(kuang)(kuang)下(xia)(xia)，用(yong)戶用(yong)電(dian)量增(zeng)加而引起(qi)的(de)，它往(wang)往(wang)使變(bian)壓(ya)器(qi)溫度升(sheng)高，促使變(bian)壓(ya)器(qi)絕緣老化，降低使用(yong)壽命，所(suo)以不允(yun)許(xu)變(bian)壓(ya)器(qi)過(guo)(guo)負荷(he)(he)(he)運(yun)行(xing)。特殊情況(kuang)(kuang)下(xia)(xia)變(bian)壓(ya)器(qi)短時間(jian)內的(de)過(guo)(guo)負荷(he)(he)(he)運(yun)行(xing)，也不能超過(guo)(guo)額定負荷(he)(he)(he)的(de)30%(冬季(ji))，在夏(xia)季(ji)不得超過(guo)(guo)15%。

9、變壓器初級線圈與次級線圈的電流關系是怎樣的？

當變(bian)壓器帶有負載(zai)運行時， 次(ci)(ci)級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)電(dian)流(liu)(liu)(liu)的(de)變(bian)化(hua)， 會引起(qi)初級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)電(dian)流(liu)(liu)(liu)相應的(de)變(bian)化(hua)。根據(ju)磁勢平(ping)衡原理推導出， 初級(ji)(ji)(ji)(ji)(ji)民次(ci)(ci)級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)的(de)電(dian)流(liu)(liu)(liu)和線(xian)圈(quan)匝數(shu)(shu)成反比(bi)， 匝數(shu)(shu)多的(de)一(yi)邊電(dian)流(liu)(liu)(liu)就小，匝數(shu)(shu)少的(de)一(yi)邊電(dian)流(liu)(liu)(liu)就大(da)， 可(ke)用下式表(biao)示(shi)：初級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)電(dian)流(liu)(liu)(liu)/次(ci)(ci)級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)電(dian)流(liu)(liu)(liu)=次(ci)(ci)級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)匝數(shu)(shu)/初級(ji)(ji)(ji)(ji)(ji)線(xian)圈(quan)匝數(shu)(shu)。

10、怎樣選擇變壓器？如何確定變壓器的合理容量？

首先要(yao)調查(cha)用(yong)(yong)電(dian)(dian)(dian)地方的電(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)壓，用(yong)(yong)戶的實際(ji)用(yong)(yong)電(dian)(dian)(dian)負荷和(he)所在(zai)地方的條件(jian)，然后參(can)照變壓器銘(ming)牌標示的技術(shu)數據逐一(yi)選(xuan)擇，一(yi)般應從變壓器容量(liang)(liang)、電(dian)(dian)(dian)壓、電(dian)(dian)(dian)流及環境條件(jian)綜(zong)合考(kao)慮，其(qi)中容量(liang)(liang)選(xuan)擇應根據用(yong)(yong)戶用(yong)(yong)電(dian)(dian)(dian)設備的容量(liang)(liang)、性質和(he)使用(yong)(yong)時間來確定所需(xu)的負荷量(liang)(liang)，以此來選(xuan)擇變壓器容量(liang)(liang)。

在正常運行時(shi)，應使(shi)變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)承受(shou)的(de)用(yong)電負(fu)荷為(wei)變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)額(e)定(ding)容量的(de)75～90%左右(you)。運行中如(ru)實測出(chu)變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)實際(ji)承受(shou)負(fu)荷50小(xiao)(xiao)于%時(shi)，應更(geng)換小(xiao)(xiao)容量變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)，如(ru)大于變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)額(e)定(ding)容量應立即更(geng)換大變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)。同(tong)時(shi)，在選(xuan)擇(ze)變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)根據線(xian)路電源(yuan)決(jue)定(ding)變(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)的(de)初級線(xian)圈(quan)電壓(ya)(ya)(ya)值(zhi)，根據用(yong)電設備(bei)選(xuan)擇(ze)次級線(xian)圈(quan)的(de)電壓(ya)(ya)(ya)值(zhi)，最好選(xuan)為(wei)低(di)壓(ya)(ya)(ya)三相四(si)線(xian)制供(gong)電。這樣可同(tong)時(shi)提供(gong)動力用(yong)電和照明(ming)用(yong)電。

對于電流(liu)的選擇要注意負荷在電動(dong)(dong)機(ji)起動(dong)(dong)時能(neng)滿(man)足(zu)電動(dong)(dong)機(ji)的要求(因(yin)為(wei)電動(dong)(dong)機(ji)起動(dong)(dong)電流(liu)要比下(xia)沉運行時大4～7倍(bei))