在(zai)供配電(dian)系統中，是(shi)一種(zhong)技術上最重(zhong)要、經濟(ji)上最昂貴的(de)電(dian)氣(qi)設(she)備，必須(xu)根據變壓器可(ke)能發生的(de)故障和不正常(chang)運行狀態、以及變壓器的(de)容量大(da)小和重(zhong)要程(cheng)度裝設(she)相應(ying)的(de)保(bao)護裝置與保(bao)護措施。本(ben)文(wen)談談幾種(zhong)電(dian)力變壓器的(de)保(bao)護措施。

　　電力變(bian)壓器故障主要是變(bian)壓器繞組及其引出線的相間短路(lu)、繞組匝(za)間短路(lu)和中性點(dian)接地(di)側單相接地(di)短路(lu)，不(bu)正常運行(xing)狀態(tai)主要是變(bian)壓器過負荷、油面(mian)降(jiang)低、溫度升高或油箱(xiang)壓力升高或冷(leng)卻系統故障。根據上述可(ke)能發生的故障及不(bu)正常運行(xing)狀態(tai)，變(bian)壓器一般(ban)要裝設一些(xie)保護裝置。

　　變壓器的保護裝置

　　變(bian)(bian)壓(ya)(ya)器(qi)的常(chang)有(you)保(bao)(bao)護(hu)(hu)裝(zhuang)置(zhi)一(yi)般包括：電(dian)流速(su)斷(duan)保(bao)(bao)護(hu)(hu)、過(guo)(guo)(guo)電(dian)流保(bao)(bao)護(hu)(hu)、縱聯差動(dong)保(bao)(bao)護(hu)(hu)、瓦斯(si)(si)保(bao)(bao)護(hu)(hu)、過(guo)(guo)(guo)負荷(he)保(bao)(bao)護(hu)(hu)、單相接地短路(lu)保(bao)(bao)護(hu)(hu)等。電(dian)流速(su)斷(duan)保(bao)(bao)護(hu)(hu)用(yong)來(lai)(lai)防(fang)御變(bian)(bian)壓(ya)(ya)器(qi)內(nei)(nei)部故障(zhang)(zhang)及(ji)電(dian)源(yuan)側(ce)引(yin)出線(xian)(xian)套管(guan)的故障(zhang)(zhang)，是(shi)變(bian)(bian)壓(ya)(ya)器(qi)的主(zhu)保(bao)(bao)護(hu)(hu)之一(yi)，瞬時動(dong)作(zuo)于電(dian)源(yuan)側(ce)斷(duan)路(lu)器(qi)跳(tiao)閘，并發出信(xin)號，但變(bian)(bian)壓(ya)(ya)器(qi)內(nei)(nei)部某些位置(zhi)故障(zhang)(zhang)及(ji)負荷(he)側(ce)引(yin)出線(xian)(xian)套管(guan)故障(zhang)(zhang)時電(dian)流速(su)斷(duan)保(bao)(bao)護(hu)(hu)不動(dong)作(zuo)。過(guo)(guo)(guo)電(dian)流保(bao)(bao)護(hu)(hu)用(yong)來(lai)(lai)防(fang)御變(bian)(bian)壓(ya)(ya)器(qi)內(nei)(nei)部和外(wai)部故障(zhang)(zhang)。縱聯差動(dong)保(bao)(bao)護(hu)(hu)用(yong)來(lai)(lai)防(fang)御變(bian)(bian)壓(ya)(ya)器(qi)內(nei)(nei)部故障(zhang)(zhang)及(ji)引(yin)出線(xian)(xian)套管(guan)的故障(zhang)(zhang)。瓦斯(si)(si)保(bao)(bao)護(hu)(hu)用(yong)來(lai)(lai)防(fang)御油浸式電(dian)力變(bian)(bian)壓(ya)(ya)器(qi)的內(nei)(nei)部故障(zhang)(zhang)。過(guo)(guo)(guo)負荷(he)保(bao)(bao)護(hu)(hu)用(yong)來(lai)(lai)通告(gao)變(bian)(bian)壓(ya)(ya)器(qi)過(guo)(guo)(guo)負荷(he)運(yun)行狀態。當變(bian)(bian)壓(ya)(ya)器(qi)的實際運(yun)行負荷(he)超(chao)過(guo)(guo)(guo)其(qi)額定(ding)容(rong)量一(yi)定(ding)比例時，過(guo)(guo)(guo)負荷(he)保(bao)(bao)護(hu)(hu)一(yi)般延時動(dong)作(zuo)于信(xin)號，也可(ke)以延時跳(tiao)閘，或延時自動(dong)減負荷(he)。

　　變壓器的電流速斷保護、過電流保護和過負荷保護

　　1、變壓器的電流速斷保護

　　變(bian)(bian)壓(ya)器(qi)(qi)(qi)的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)，其組(zu)成、原理與線(xian)路(lu)的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)完全(quan)相(xiang)(xiang)同，對于企業供電(dian)(dian)(dian)(dian)采用的(de)(de)(de)降壓(ya)變(bian)(bian)壓(ya)器(qi)(qi)(qi)的(de)(de)(de)繼電(dian)(dian)(dian)(dian)保(bao)護(hu)(hu)裝(zhuang)置(zhi)，其電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)互感器(qi)(qi)(qi)安裝(zhuang)在變(bian)(bian)壓(ya)器(qi)(qi)(qi)的(de)(de)(de)高(gao)壓(ya)電(dian)(dian)(dian)(dian)源側。變(bian)(bian)壓(ya)器(qi)(qi)(qi)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)動(dong)作(zuo)(zuo)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)（速(su)(su)斷(duan)(duan)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)）的(de)(de)(de)整定計算也(ye)與線(xian)路(lu)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)基本(ben)相(xiang)(xiang)同。變(bian)(bian)壓(ya)器(qi)(qi)(qi)的(de)(de)(de)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)與線(xian)路(lu)電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)一樣，存有“死(si)區(qu)”，如變(bian)(bian)壓(ya)器(qi)(qi)(qi)內部(bu)某些(xie)位(wei)置(zhi)兩相(xiang)(xiang)短路(lu)故(gu)障(zhang)(zhang)、靠近(jin)中(zhong)性點繞組(zu)三相(xiang)(xiang)短路(lu)故(gu)障(zhang)(zhang)及低壓(ya)負荷側引出(chu)線(xian)套管三相(xiang)(xiang)短路(lu)故(gu)障(zhang)(zhang)時電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)不(bu)動(dong)作(zuo)(zuo)。彌補死(si)區(qu)的(de)(de)(de)措施，也(ye)是配備(bei)帶(dai)時限的(de)(de)(de)過電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)保(bao)護(hu)(hu)，而瓦(wa)斯保(bao)護(hu)(hu)也(ye)能彌補電(dian)(dian)(dian)(dian)流(liu)(liu)(liu)(liu)速(su)(su)斷(duan)(duan)保(bao)護(hu)(hu)在變(bian)(bian)壓(ya)器(qi)(qi)(qi)內部(bu)的(de)(de)(de)保(bao)護(hu)(hu)死(si)區(qu)。

　　變(bian)壓(ya)器(qi)(qi)(qi)(qi)在(zai)空(kong)載投入或短路切除后(hou)電(dian)(dian)(dian)壓(ya)突(tu)然恢復時將出現一個沖(chong)擊性的(de)(de)(de)(de)勵磁(ci)涌流(liu)，為(wei)了避免(mian)電(dian)(dian)(dian)流(liu)速斷(duan)(duan)(duan)保(bao)護(hu)(hu)誤動(dong)作(zuo)(zuo)，通常在(zai)速斷(duan)(duan)(duan)電(dian)(dian)(dian)流(liu)整定后(hou)，在(zai)變(bian)壓(ya)器(qi)(qi)(qi)(qi)開始運行時，應(ying)將變(bian)壓(ya)器(qi)(qi)(qi)(qi)空(kong)載試投若干次，以檢查速斷(duan)(duan)(duan)保(bao)護(hu)(hu)是否誤動(dong)作(zuo)(zuo)，如果(guo)動(dong)作(zuo)(zuo)，應(ying)將速斷(duan)(duan)(duan)保(bao)護(hu)(hu)的(de)(de)(de)(de)動(dong)作(zuo)(zuo)電(dian)(dian)(dian)流(liu)適(shi)當增(zeng)大，直到使速斷(duan)(duan)(duan)保(bao)護(hu)(hu)不動(dong)作(zuo)(zuo)。運行經驗證(zheng)實(shi)，速斷(duan)(duan)(duan)保(bao)護(hu)(hu)的(de)(de)(de)(de)動(dong)作(zuo)(zuo)電(dian)(dian)(dian)流(liu)只要大于變(bian)壓(ya)器(qi)(qi)(qi)(qi)一次額定電(dian)(dian)(dian)流(liu)的(de)(de)(de)(de)3～5倍，即可避免(mian)流(liu)過勵磁(ci)涌流(liu)時錯誤地斷(duan)(duan)(duan)開變(bian)壓(ya)器(qi)(qi)(qi)(qi)。變(bian)壓(ya)器(qi)(qi)(qi)(qi)電(dian)(dian)(dian)流(liu)速斷(duan)(duan)(duan)保(bao)護(hu)(hu)具有接線簡單、動(dong)作(zuo)(zuo)迅(xun)速等優點(dian)，但它不能保(bao)護(hu)(hu)變(bian)壓(ya)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)全(quan)部，因此(ci)不能單獨作(zuo)(zuo)為(wei)變(bian)壓(ya)器(qi)(qi)(qi)(qi)的(de)(de)(de)(de)主保(bao)護(hu)(hu)。

　　2、變壓器(qi)的過電流(liu)保護(hu)

　　變(bian)壓(ya)器(qi)的(de)過(guo)電(dian)流(liu)保(bao)(bao)護，用來作為(wei)變(bian)壓(ya)器(qi)瓦斯保(bao)(bao)護和電(dian)流(liu)速斷保(bao)(bao)護或差動(dong)保(bao)(bao)護的(de)近后備保(bao)(bao)護，同(tong)(tong)時又可(ke)作為(wei)變(bian)壓(ya)器(qi)低(di)壓(ya)出線(xian)或設備的(de)遠后備保(bao)(bao)護，同(tong)(tong)樣可(ke)稱其為(wei)未設保(bao)(bao)護的(de)低(di)壓(ya)母線(xian)及(ji)變(bian)壓(ya)器(qi)電(dian)流(liu)速斷保(bao)(bao)護死(si)區的(de)基本保(bao)(bao)護。無(wu)論(lun)采用電(dian)流(liu)繼電(dian)器(qi)還(huan)是(shi)采用脫(tuo)扣器(qi)，也無(wu)論(lun)是(shi)定時限(xian)還(huan)是(shi)反時限(xian)，變(bian)壓(ya)器(qi)過(guo)電(dian)流(liu)保(bao)(bao)護的(de)組成、原(yuan)理與線(xian)路(lu)過(guo)電(dian)流(liu)保(bao)(bao)護的(de)組成、原(yuan)理完全相(xiang)同(tong)(tong)。

　　變壓(ya)器(qi)過電流(liu)(liu)保護(hu)的(de)動作(zuo)時限(xian)亦按“階梯原則”整定(ding)(ding)，與線(xian)(xian)路過電流(liu)(liu)保護(hu)完全(quan)相(xiang)同(tong)。但是對車間(jian)(jian)變電所（電力系統的(de)終端(duan)變電所），其(qi)動作(zuo)時間(jian)(jian)可整定(ding)(ding)為最小(xiao)值（0.5～0.7s），這樣可省(sheng)去電流(liu)(liu)速斷保護(hu)。變壓(ya)器(qi)過電流(liu)(liu)保護(hu)的(de)靈敏度，應按變壓(ya)器(qi)低壓(ya)側母(mu)線(xian)(xian)在(zai)系統最小(xiao)運行方式下發生(sheng)兩相(xiang)短路時，高壓(ya)側流(liu)(liu)經保護(hu)裝(zhuang)(zhuang)置安(an)裝(zhuang)(zhuang)處的(de)電流(liu)(liu)互感(gan)器(qi)的(de)穿(chuan)越電流(liu)(liu)值來校驗。

　　3、變壓器的(de)過負荷保護

　　對于，在維持變(bian)(bian)(bian)壓器規定的(de)使用年限不變(bian)(bian)(bian)的(de)情況下，允許變(bian)(bian)(bian)壓器適當過(guo)負荷運(yun)行。但是，當變(bian)(bian)(bian)壓器實際負荷超(chao)過(guo)其額定容量20%（室內(nei)）或30%（室外）時(shi)(shi)，過(guo)負荷保(bao)護應延(yan)時(shi)(shi)10s～15s動作(zuo)于信(xin)號，以便運(yun)行人員及時(shi)(shi)查找原因。變(bian)(bian)(bian)壓器過(guo)負荷保(bao)護的(de)動作(zuo)電流(liu)應按躲過(guo)變(bian)(bian)(bian)壓器正常過(guo)負荷電流(liu)來整(zheng)定。變(bian)(bian)(bian)壓器過(guo)負荷保(bao)護的(de)動作(zuo)時(shi)(shi)限一(yi)般取(qu)10s～15s，以躲過(guo)尖峰電流(liu)，避免誤(wu)發(fa)信(xin)號。

　　變壓器低壓側的單相短路保護

　　對變壓器低壓側的單(dan)相（接(jie)地）短路，可采取(qu)下(xia)列有效保護措施之一。

　　1、在(zai)變壓器(qi)(qi)低壓側裝設(she)三相都帶過流脫(tuo)扣器(qi)(qi)的低壓斷(duan)路器(qi)(qi)

　　小(xiao)型企(qi)業變電所或車間變電所變壓器(qi)低(di)(di)(di)壓側一般裝(zhuang)設容量較(jiao)大(da)的低(di)(di)(di)壓斷路(lu)器(qi)，作為控制低(di)(di)(di)壓母線上所有(you)負荷的總開關。這(zhe)種低(di)(di)(di)壓斷路(lu)器(qi)，不僅裝(zhuang)有(you)三(san)相過流脫扣(kou)(kou)器(qi)，能(neng)夠(gou)實現(xian)(xian)(xian)低(di)(di)(di)壓側的相間短路(lu)和(he)單相短路(lu)保(bao)護(hu)(hu)；而且裝(zhuang)有(you)失(shi)壓脫扣(kou)(kou)器(qi)和(he)熱脫扣(kou)(kou)器(qi)，能(neng)夠(gou)實現(xian)(xian)(xian)失(shi)壓、欠壓（低(di)(di)(di)電壓）保(bao)護(hu)(hu)和(he)過負荷保(bao)護(hu)(hu)；同時還裝(zhuang)有(you)分(fen)勵(li)脫扣(kou)(kou)器(qi)和(he)司(si)服電動機，能(neng)夠(gou)實現(xian)(xian)(xian)電動分(fen)，合閘(zha)及變壓器(qi)保(bao)護(hu)(hu)聯動跳閘(zha)。所以(yi)，這(zhe)項措施應用最廣。

　　2、在變壓器低(di)壓側裝設熔斷器

　　低壓(ya)熔(rong)(rong)斷器也可以用(yong)來作(zuo)低壓(ya)側的相(xiang)間短路和單相(xiang)短路保護，但熔(rong)(rong)斷器不能作(zuo)控制(zhi)開關使用(yong)，而(er)且它(ta)熔(rong)(rong)斷后需更換熔(rong)(rong)體才能恢復供電，因此僅限于用(yong)在給不重要負荷供電的變壓(ya)器。

　　3、在變壓器低壓側(ce)中性點引出(chu)線上(shang)裝設零序(xu)電流(liu)保護

　　這種零(ling)序(xu)(xu)電(dian)(dian)(dian)流保護(hu)是將(jiang)一只(zhi)零(ling)序(xu)(xu)電(dian)(dian)(dian)流互(hu)感器(qi)(qi)裝(zhuang)在變(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)低壓(ya)(ya)側中性點引(yin)出線上(shang)，互(hu)感器(qi)(qi)二次側接一只(zhi)電(dian)(dian)(dian)流繼電(dian)(dian)(dian)器(qi)(qi)，反應(ying)低壓(ya)(ya)側的單相短路電(dian)(dian)(dian)流。根據變(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)運行規程要求，某(mou)些連接的變(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)二次側單相不(bu)平衡負(fu)荷不(bu)得超過額定(ding)(ding)容量(liang)的25%。因此，變(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)零(ling)序(xu)(xu)電(dian)(dian)(dian)流保護(hu)的動(dong)作電(dian)(dian)(dian)流按躲過變(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)低壓(ya)(ya)側更大(da)不(bu)平衡電(dian)(dian)(dian)流來整定(ding)(ding)。這項措(cuo)施大(da)大(da)提高了變(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)低壓(ya)(ya)側的單相短路保護(hu)的靈敏度。但(dan)缺點是要單獨裝(zhuang)設一套零(ling)序(xu)(xu)電(dian)(dian)(dian)流保護(hu)裝(zhuang)置，投資較多。

　　變壓器的瓦斯保護

　　瓦(wa)斯(si)(si)保(bao)護(hu)(hu)(hu)主要是(shi)利用變(bian)壓(ya)(ya)器油(you)(you)等受熱產(chan)生氣(qi)體而動作(zuo)的(de)(de)一(yi)種(zhong)(zhong)(zhong)保(bao)護(hu)(hu)(hu)，又稱氣(qi)體繼(ji)電保(bao)護(hu)(hu)(hu)，是(shi)反應油(you)(you)浸(jin)式電力變(bian)壓(ya)(ya)器油(you)(you)箱(xiang)內(nei)部繞組故(gu)障(zhang)(zhang)的(de)(de)一(yi)種(zhong)(zhong)(zhong)基(ji)本(ben)保(bao)護(hu)(hu)(hu)裝(zhuang)置。瓦(wa)斯(si)(si)保(bao)護(hu)(hu)(hu)的(de)(de)主要元(yuan)件是(shi)氣(qi)體繼(ji)電器，在(zai)出廠時(shi)就已(yi)裝(zhuang)設在(zai)變(bian)壓(ya)(ya)器的(de)(de)油(you)(you)箱(xiang)與油(you)(you)枕之間(jian)的(de)(de)聯通管上(shang)。當變(bian)壓(ya)(ya)器油(you)(you)箱(xiang)內(nei)部發生故(gu)障(zhang)(zhang)時(shi)，可使氣(qi)流(liu)通過氣(qi)體繼(ji)電器進入油(you)(you)枕，并能(neng)(neng)(neng)(neng)防止氣(qi)泡聚積在(zai)變(bian)壓(ya)(ya)器的(de)(de)頂蓋內(nei)。瓦(wa)斯(si)(si)保(bao)護(hu)(hu)(hu)動作(zuo)迅速、靈敏度高、接線(xian)和(he)安(an)裝(zhuang)簡(jian)單、能(neng)(neng)(neng)(neng)反應變(bian)壓(ya)(ya)器油(you)(you)箱(xiang)內(nei)部各(ge)種(zhong)(zhong)(zhong)類型的(de)(de)故(gu)障(zhang)(zhang)。但是(shi)瓦(wa)斯(si)(si)保(bao)護(hu)(hu)(hu)不(bu)能(neng)(neng)(neng)(neng)反應變(bian)壓(ya)(ya)器油(you)(you)箱(xiang)外的(de)(de)套管和(he)斷路器之間(jian)連接線(xian)上(shang)的(de)(de)故(gu)障(zhang)(zhang)。因此，它不(bu)能(neng)(neng)(neng)(neng)作(zuo)為防御變(bian)壓(ya)(ya)器各(ge)種(zhong)(zhong)(zhong)故(gu)障(zhang)(zhang)的(de)(de)保(bao)護(hu)(hu)(hu)。