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變壓(ya)(ya)器(qi)是電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)改變電(dian)(dian)(dian)(dian)壓(ya)(ya)和傳輸電(dian)(dian)(dian)(dian)能(neng)的(de)(de)電(dian)(dian)(dian)(dian)氣設備，是電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)向(xiang)用戶供電(dian)(dian)(dian)(dian)的(de)(de)載(zai)體。變壓(ya)(ya)器(qi)的(de)(de)安全可靠運(yun)行是萬家燈。然(ran)而，由(you)于電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)運(yun)行中的(de)(de)許多原因，變壓(ya)(ya)器(qi)的(de)(de)絕緣水平相對較弱(ruo)，變壓(ya)(ya)器(qi)損壞(huai)(huai)的(de)(de)概率最大。由(you)于某(mou)種原因，電(dian)(dian)(dian)(dian)網(wang)(wang)(wang)運(yun)行過電(dian)(dian)(dian)(dian)壓(ya)(ya)會(hui)損壞(huai)(huai)變壓(ya)(ya)器(qi)，其絕緣水平主要由(you)雷電(dian)(dian)(dian)(dian)擊耐(nai)電(dian)(dian)(dian)(dian)壓(ya)(ya)和工(gong)頻耐(nai)電(dian)(dian)(dian)(dian)壓(ya)(ya)決定。
過電(dian)(dian)壓是指對(dui)絕緣有危險的(de)突(tu)然電(dian)(dian)壓升高(gao)。這種(zhong)異常(chang)電(dian)(dian)壓升高(gao)的(de)幅(fu)值(zhi)可以達到設備額定電(dian)(dian)壓的(de)幾倍以上，嚴重(zhong)威脅變壓器(qi)(qi)絕緣的(de)安全。如(ru)果過電(dian)(dian)壓持續時間長，會損壞變壓器(qi)(qi)。為(wei)(wei)了保證(zheng)電(dian)(dian)網運行中變壓器(qi)(qi)的(de)安全，除了選擇高(gao)質量的(de)變壓器(qi)(qi)外(wai)，還應為(wei)(wei)變壓器(qi)(qi)設置合理有效的(de)過電(dian)(dian)壓保護措施。
電(dian)網過(guo)電(dian)壓對變(bian)壓器的(de)危害
真正影響變壓(ya)(ya)器絕緣(yuan)和(he)保護(hu)裝置的(de)(de)(de)(de)電(dian)網中(zhong)產生的(de)(de)(de)(de)幾種過電(dian)壓(ya)(ya)主要取決于過電(dian)壓(ya)(ya)的(de)(de)(de)(de)波(bo)(bo)(bo)形(xing)。幅值(zhi)和(he)持續時間。設(she)備(bei)絕緣(yuan)水平的(de)(de)(de)(de)電(dian)壓(ya)(ya)波(bo)(bo)(bo)形(xing)有三種：短波(bo)(bo)(bo)前(qian)雷(lei)電(dian)波(bo)(bo)(bo)、長波(bo)(bo)(bo)前(qian)操作(zuo)(zuo)波(bo)(bo)(bo)和(he)低頻電(dian)壓(ya)(ya)波(bo)(bo)(bo)。設(she)備(bei)絕緣(yuan)對(dui)雷(lei)電(dian)，操作(zuo)(zuo)或工頻電(dian)壓(ya)(ya)的(de)(de)(de)(de)耐受性(xing)應由相(xiang)應的(de)(de)(de)(de)波(bo)(bo)(bo)形(xing)電(dian)壓(ya)(ya)檢查。
在(zai)(zai)過(guo)電(dian)(dian)壓(ya)(ya)損壞(huai)變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)的(de)事故中(zhong)，絕緣擊(ji)穿損壞(huai)的(de)概率最高(gao)。當電(dian)(dian)網(wang)遭受(shou)雷(lei)(lei)擊(ji)時(shi)(shi)，線路(lu)導(dao)線上會產(chan)(chan)生(sheng)振幅(fu)大、作用時(shi)(shi)間短(duan)的(de)非周期(qi)性(xing)脈沖電(dian)(dian)壓(ya)(ya)波(bo)(bo)。它以光(guang)速沿線傳輸。首(shou)先，它在(zai)(zai)線路(lu)避雷(lei)(lei)器(qi)(qi)上放(fang)電(dian)(dian)，余(yu)波(bo)(bo)通過(guo)變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)進入地面。當余(yu)波(bo)(bo)通過(guo)變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)保護的(de)避雷(lei)(lei)器(qi)(qi)時(shi)(shi)，它會在(zai)(zai)變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)上產(chan)(chan)生(sheng)電(dian)(dian)壓(ya)(ya)降（殘(can)壓(ya)(ya)）。如果變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)與避雷(lei)(lei)器(qi)(qi)之間有一(yi)定(ding)的(de)電(dian)(dian)氣(qi)距(ju)離(li)，殘(can)壓(ya)(ya)會在(zai)(zai)進入前振蕩導(dao)線，導(dao)致(zhi)(zhi)電(dian)(dian)壓(ya)(ya)升高(gao)，導(dao)致(zhi)(zhi)增加在(zai)(zai)變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)上的(de)電(dian)(dian)壓(ya)(ya)高(gao)于殘(can)壓(ya)(ya)，從(cong)而(er)威脅變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)的(de)絕緣安全。因此，在(zai)(zai)安裝變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)保護避雷(lei)(lei)器(qi)(qi)時(shi)(shi)，應盡量保持避雷(lei)(lei)器(qi)(qi)與變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)零距(ju)離(li)。
電(dian)網中的諧(xie)振過(guo)電(dian)壓或操作過(guo)電(dian)壓也較高，持(chi)續時間較長。它還會(hui)威脅變(bian)壓器的安全(quan)運行，甚至導致絕緣(yuan)擊穿和損壞(huai)變(bian)壓器。
此(ci)外，逆(ni)變(bian)(bian)(bian)換過(guo)(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)對變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)的危害也(ye)(ye)不(bu)容忽視。當變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)采(cai)用避雷器(qi)(qi)(qi)進行防雷保護(hu)時，避雷器(qi)(qi)(qi)接地(di)(di)(di)線、變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)中(zhong)性線和(he)變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)外殼采(cai)用三(san)位一體(ti)接地(di)(di)(di)。如果(guo)高(gao)壓(ya)(ya)(ya)側在(zai)變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)運行過(guo)(guo)程中(zhong)發生雷擊(ji)，則會(hui)(hui)(hui)引(yin)起避雷器(qi)(qi)(qi)放電(dian)(dian)(dian)(dian)，產生的殘壓(ya)(ya)(ya)作(zuo)用在(zai)高(gao)壓(ya)(ya)(ya)繞(rao)組上(shang)。由于高(gao)壓(ya)(ya)(ya)繞(rao)組阻抗(kang)(kang)大，容抗(kang)(kang)小，雷電(dian)(dian)(dian)(dian)流(liu)只(zhi)流(liu)過(guo)(guo)高(gao)壓(ya)(ya)(ya)繞(rao)組和(he)對地(di)(di)(di)電(dian)(dian)(dian)(dian)容。當電(dian)(dian)(dian)(dian)路通(tong)(tong)過(guo)(guo)接地(di)(di)(di)點放電(dian)(dian)(dian)(dian)時，接地(di)(di)(di)電(dian)(dian)(dian)(dian)阻上(shang)會(hui)(hui)(hui)產生很大的沖(chong)擊(ji)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)降，低(di)壓(ya)(ya)(ya)繞(rao)組也(ye)(ye)會(hui)(hui)(hui)通(tong)(tong)過(guo)(guo)中(zhong)性線施加，低(di)壓(ya)(ya)(ya)繞(rao)組通(tong)(tong)過(guo)(guo)雷電(dian)(dian)(dian)(dian)流(liu)產生磁(ci)通(tong)(tong)。根據(ju)電(dian)(dian)(dian)(dian)磁(ci)感(gan)應(ying)原理，該磁(ci)通(tong)(tong)將根據(ju)變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)在(zai)高(gao)壓(ya)(ya)(ya)繞(rao)組上(shang)的變(bian)(bian)(bian)化產生高(gao)感(gan)應(ying)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，稱為(wei)逆(ni)變(bian)(bian)(bian)換過(guo)(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)。電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)幅值比殘壓(ya)(ya)(ya)大幾(ji)(ji)倍(bei)到幾(ji)(ji)十倍(bei)，也(ye)(ye)會(hui)(hui)(hui)造成變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)(qi)(qi)絕(jue)緣的擊(ji)穿和(he)損壞。
保護變壓(ya)器中性點過電壓(ya)
變(bian)(bian)電站位于多雷(lei)區，單電源進線，三相雷(lei)電侵入波(bo)的概率(lv)較大(da)，因此主變(bian)(bian)壓(ya)器(qi)中(zhong)性(xing)點(dian)(dian)需要安裝避(bi)雷(lei)器(qi)保(bao)護(hu)。變(bian)(bian)壓(ya)器(qi)中(zhong)性(xing)點(dian)(dian)過電壓(ya)保(bao)護(hu)的設(she)置(zhi)可以(yi)單獨設(she)置(zhi)門保(bao)護(hu)變(bian)(bian)壓(ya)器(qi)中(zhong)性(xing)點(dian)(dian)的設(she)置(zhi)，專門保(bao)護(hu)變(bian)(bian)壓(ya)器(qi)中(zhong)性(xing)點(dian)(dian)的無間隙氧化鋅避(bi)雷(lei)器(qi)（以(yi)下(xia)簡稱中(zhong)性(xing)點(dian)(dian)MOA）。中(zhong)性(xing)點(dian)(dian)MOA可以(yi)保(bao)護(hu)雷(lei)電過電壓(ya)和操作過電壓(ya)。其(qi)優點(dian)(dian)是動作靈敏，殘壓(ya)低，通(tong)流容量大(da)，對(dui)保(bao)護(hu)主變(bian)(bian)壓(ya)器(qi)中(zhong)性(xing)點(dian)(dian)免受過電壓(ya)有(you)很(hen)好(hao)的效果(guo)。
此外，目前中(zhong)性點(dian)MOA的額定電壓(ya)較高，當中(zhong)性點(dian)電位偏差(cha)不(bu)大時，MOA仍具有(you)良好的保護效(xiao)果。如果有(you)效(xiao)的接(jie)地系(xi)統(tong)發生單相接(jie)地故(gu)障，主變壓(ya)器的中(zhong)性點(dian)將產生兩倍的工(gong)頻相電壓(ya)，不(bu)會(hui)損壞MOA。
如果中性(xing)點(dian)(dian)電(dian)(dian)位嚴重偏離，避(bi)雷(lei)(lei)(lei)器(qi)(qi)運行中的安全將(jiang)受到(dao)威脅(xie)。當中性(xing)點(dian)(dian)過(guo)(guo)電(dian)(dian)壓達(da)到(dao)工(gong)頻相(xiang)電(dian)(dian)壓的兩倍以上(shang)(shang)時，避(bi)雷(lei)(lei)(lei)器(qi)(qi)會因(yin)流量不(bu)足而損壞，可(ke)能危及主(zhu)變的安全。雖然(ran)這(zhe)種情(qing)況發生的概(gai)率很小(xiao)，但為了安全主(zhu)變，除了中性(xing)點(dian)(dian)MOA保(bao)(bao)護(hu)(hu)主(zhu)變中性(xing)點(dian)(dian)過(guo)(guo)電(dian)(dian)壓外，避(bi)雷(lei)(lei)(lei)器(qi)(qi)邊緣的并聯水平棒間(jian)隙(xi)也(ye)可(ke)以限制工(gong)頻過(guo)(guo)電(dian)(dian)壓。棒間(jian)隙(xi)并聯避(bi)雷(lei)(lei)(lei)器(qi)(qi)的保(bao)(bao)護(hu)(hu)作用是:雷(lei)(lei)(lei)電(dian)(dian)，操(cao)作過(guo)(guo)電(dian)(dian)壓由(you)避(bi)雷(lei)(lei)(lei)器(qi)(qi)保(bao)(bao)護(hu)(hu)，間(jian)隙(xi)用于(yu)限制避(bi)雷(lei)(lei)(lei)器(qi)(qi)上(shang)(shang)振幅較(jiao)高的工(gong)頻過(guo)(guo)電(dian)(dian)壓。這(zhe)種保(bao)(bao)護(hu)(hu)方法不(bu)僅保(bao)(bao)護(hu)(hu)了變壓器(qi)(qi)的中性(xing)點(dian)(dian)過(guo)(guo)電(dian)(dian)壓，而且達(da)到(dao)了相(xiang)互(hu)保(bao)(bao)護(hu)(hu)的目的。
保護三繞組變壓器
三(san)繞(rao)(rao)組(zu)(zu)變壓器(qi)有三(san)個高、中(zhong)、低壓繞(rao)(rao)組(zu)(zu)。如果在運行過程中(zhong)被(bei)雷擊(ji)高壓側的(de)雷電波侵(qin)入，過電壓將通(tong)過靜(jing)電耦合和電磁感(gan)應(ying)傳遞給低壓繞(rao)(rao)組(zu)(zu)。在高、中(zhong)壓繞(rao)(rao)組(zu)(zu)運行、低壓繞(rao)(rao)組(zu)(zu)開路時(shi)，低壓繞(rao)(rao)組(zu)(zu)對(dui)地(di)電容值較小，繞(rao)(rao)組(zu)(zu)上的(de)靜(jing)電感(gan)應(ying)電壓分量可達到較高值，危及(ji)低壓繞(rao)(rao)組(zu)(zu)的(de)絕緣(yuan)安全。為了限制(zhi)過電壓的(de)危害，低壓繞(rao)(rao)組(zu)(zu)應(ying)在出口外安裝避雷器(qi)進行保護。
在變壓(ya)(ya)(ya)器(qi)運行過(guo)程中，如(ru)果系統出現不對稱接地(di)故障或斷路器(qi)的(de)非全(quan)相動作(zuo)和(he)零序電(dian)(dian)壓(ya)(ya)(ya)，電(dian)(dian)壓(ya)(ya)(ya)將(jiang)通過(guo)電(dian)(dian)容耦合(he)傳輸到(dao)低(di)壓(ya)(ya)(ya)繞組。由于這種電(dian)(dian)壓(ya)(ya)(ya)具有工頻過(guo)電(dian)(dian)壓(ya)(ya)(ya)的(de)特(te)性，也(ye)會危及低(di)壓(ya)(ya)(ya)繞組絕緣的(de)安全(quan)。因此，除了同期(qi)性能好的(de)斷路器(qi)外，變壓(ya)(ya)(ya)器(qi)低(di)壓(ya)(ya)(ya)側母線橋(qiao)上通常(chang)安裝3個Y。接線電(dian)(dian)容器(qi)用于增加低(di)壓(ya)(ya)(ya)側對地(di)電(dian)(dian)容器(qi)，能有效吸收和(he)降低(di)過(guo)壓(ya)(ya)(ya)幅值和(he)陡度，從而(er)保護過(guo)壓(ya)(ya)(ya)。
保(bao)護變壓器低(di)壓系統
變壓(ya)(ya)器(qi)(qi)低(di)壓(ya)(ya)側(ce)供(gong)電(dian)(dian)線(xian)路長，容易(yi)受到雷(lei)電(dian)(dian)波的(de)侵襲。當低(di)壓(ya)(ya)線(xian)路受到雷(lei)擊時(shi)，電(dian)(dian)壓(ya)(ya)分別在(zai)(zai)低(di)壓(ya)(ya)繞(rao)(rao)組(zu)和接地電(dian)(dian)阻(zu)上(shang)(shang)。由于電(dian)(dian)磁(ci)感應(ying)，侵入的(de)雷(lei)電(dian)(dian)流會根(gen)據變壓(ya)(ya)器(qi)(qi)的(de)變比在(zai)(zai)高壓(ya)(ya)繞(rao)(rao)組(zu)上(shang)(shang)產(chan)生感應(ying)過(guo)電(dian)(dian)壓(ya)(ya)。為(wei)防止(zhi)逆(ni)變換過(guo)電(dian)(dian)壓(ya)(ya)對(dui)高壓(ya)(ya)繞(rao)(rao)組(zu)造成危(wei)害(hai)，低(di)壓(ya)(ya)側(ce)出口還應(ying)安裝一組(zu)金屬(shu)氧化物避(bi)雷(lei)器(qi)(qi)，以抑(yi)制低(di)壓(ya)(ya)繞(rao)(rao)組(zu)產(chan)生的(de)沖(chong)擊磁(ci)通量，從(cong)而(er)保護過(guo)電(dian)(dian)壓(ya)(ya)。
此外，由于Y、Zn11聯合組變(bian)壓(ya)器繞(rao)組結構的(de)特點(dian)，如果使用這種變(bian)壓(ya)器，對(dui)抑制逆變(bian)換過電氣也有很好的(de)效(xiao)果，可以有效(xiao)保護逆變(bian)換過電壓(ya)對(dui)變(bian)壓(ya)器的(de)損(sun)壞。
總結
變壓器(qi)(qi)(qi)是電(dian)力系統的(de)重要(yao)設(she)備，其絕緣(yuan)水(shui)平相(xiang)對(dui)較弱，過電(dian)壓損壞變壓器(qi)(qi)(qi)的(de)概率最大。為了保(bao)(bao)證變壓器(qi)(qi)(qi)的(de)安全可靠運行(xing)(xing)，除了選擇高質量(liang)的(de)變壓器(qi)(qi)(qi)外(wai)，還需要(yao)對(dui)運行(xing)(xing)的(de)變壓器(qi)(qi)(qi)設(she)置有效的(de)過電(dian)壓保(bao)(bao)護(hu)(hu)。根據電(dian)網的(de)運行(xing)(xing)特點(dian)和接地方(fang)式，變壓器(qi)(qi)(qi)中性(xing)點(dian)的(de)過電(dian)壓概率也較高。除變電(dian)站和電(dian)網的(de)過電(dian)壓保(bao)(bao)護(hu)(hu)外(wai)，還應在變壓器(qi)(qi)(qi)中性(xing)點(dian)設(she)置合理的(de)過電(dian)壓保(bao)(bao)護(hu)(hu)，以(yi)確保(bao)(bao)變壓器(qi)(qi)(qi)的(de)安全穩定運行(xing)(xing)。
綜上所述(shu)，選(xuan)擇質(zhi)量穩定的變壓(ya)器(qi)(qi)廠家尤為重要，浙權（上海）電器(qi)(qi)設備制造有限公(gong)司(si)(si)是一家集生產(chan)(chan)、研發(fa)、銷(xiao)(xiao)售(shou)為一體的專(zhuan)業(ye)性企業(ye)，本公(gong)司(si)(si)專(zhuan)業(ye)生產(chan)(chan)變壓(ya)器(qi)(qi)、穩壓(ya)器(qi)(qi)、調壓(ya)器(qi)(qi)及低壓(ya)電器(qi)(qi)配套產(chan)(chan)品，始終“堅(jian)持企業(ye)創(chuang)新，追求技(ji)術進步(bu)”是發(fa)展的一貫宗旨，公(gong)司(si)(si)擁(yong)有雄厚的技(ji)術開發(fa)力量、優質(zhi)的工藝(yi)檢測儀器(qi)(qi)和生產(chan)(chan)設備，積極引進國外的先進技(ji)術，不斷對產(chan)(chan)品加(jia)以改進和完善，多(duo)(duo)年的專(zhuan)業(ye)化管理，已成(cheng)功構建(jian)了(le)多(duo)(duo)層次的營銷(xiao)(xiao)網絡(luo)。
