變壓器鐵芯為什麼要接地?
變壓器在運行過程中,鐵芯、固定鐵芯、繞組的金屬結構、零件、零件等處於強電場,在電場的作用下,對地電位較高。如果鐵芯不接地,會與接地夾具、油箱產生電位差,在電位差的作用下可能會出現斷續放電。
引文作者:上海蓋能電氣市場部(專注幹式變壓器30年)電話:189 1886 3098(微信同號)
此外,變壓器在運行過程中,繞組周圍有很強的磁場,鐵芯、金屬結構、零件、零件等處於不均勻的磁場中,它們與繞組的距離各不相同,因此,各金屬結構、零件、零(ling)件(jian)等(deng)受(shou)磁(ci)場(chang)感(gan)應(ying)產(chan)生(sheng)的(de)電(dian)動(dong)勢(shi)大(da)小(xiao)也(ye)各(ge)不(bu)相(xiang)同(tong),彼(bi)此(ci)之(zhi)間(jian)也(ye)存(cun)在(zai)電(dian)位(wei)差(cha)。盡(jin)管(guan)電(dian)位(wei)差(cha)不(bu)大(da),但(dan)也(ye)可(ke)以(yi)破(po)壞(huai)很(hen)小(xiao)的(de)絕(jue)緣(yuan)間(jian)隙(xi),因(yin)此(ci)也(ye)可(ke)能(neng)導(dao)致(zhi)微(wei)量(liang)持(chi)續(xu)放(fang)電(dian)。
不bu管guan是shi由you於yu電dian位wei差cha的de作zuo用yong而er產chan生sheng的de斷duan續xu放fang電dian現xian象xiang,還hai是shi由you於yu絕jue緣yuan間jian隙xi較jiao小xiao而er產chan生sheng的de持chi續xu微wei量liang放fang電dian現xian象xiang,都dou是shi不bu允yun許xu的de,而er且qie很hen難nan檢jian查zha這zhe些xie斷duan續xu放fang電dian部bu位wei。
解決方案的有效方法是可靠地接地鐵芯和固定鐵芯、繞組的金屬結構、零件、lingjiandeng。,shitamenyuyouxiangchuyudimiandianwei。bianyaqidetiexinjiedishiyidianjiedi,zhinengshiyidianjiedi。yinweitiexindeguigangpianshijueyuande,zheshiweilefangzhigengdadewoliu,suoyisuoyoudeguigangpiandoubunengjiedihuoduodianjiedi,fouzehuizaochenggengdadewoliu,tiexinhuiyanzhongfare。
bianyaqidetiexinjieditongchangjieditiexinderenheguigangpian。guigangpianzhijianjueyuan,danjueyuandianzuzhixiao,bujunyundeqiangdianchangheqiangcichang,guigangpianzhongganyingdegaoyadianhekeyitongguoguigangpiancongjiedichuliuxiangdadi,dankeyizuzhiwoliucongyipianliuxianglingyipian。yinci,zhiyaojieditiexinderenheguigangpian,jiudengyujiedizhenggetiexin。
值得注意的是:變壓器的鐵芯必須是一點接地,不能是兩點接地,更不能是多點接地,因為多點接地是變壓器的常見故障之一。
為什麼變壓器鐵芯不能多接地?
由於變壓器鐵芯diepianzhinengjiediyidiandian,yinweiruguoyouliangdianyishangdejiedi,namejiedidianzhijianjiuyoukenengxingchenghuilu。dangzhucidaotongguozhegefengbihehuilushi,huichanshengxunhuandianliu,daozhineibuguoreheshigu。jubushaorongtiexinhuixingchengtiexinpianzhijiandeduanluguzhang,zengjiatiesun,yanzhongyingxiangbianyaqidexingnenghezhengchanggongzuo,zhinenggenghuantiexinguigangpianjinxingxiufu。yinci,bianyaqibuyunxuduodianjiedi,zhinengjiediyidian。
多點接地容易形成環流,容易發熱
變壓器在運行過程中,其鐵芯、夾(jia)具(ju)等(deng)金(jin)屬(shu)部(bu)件(jian)都(dou)處(chu)於(yu)強(qiang)電(dian)場(chang),因(yin)為(wei)靜(jing)電(dian)感(gan)應(ying)會(hui)在(zai)鐵(tie)芯(xin)和(he)金(jin)屬(shu)部(bu)件(jian)上(shang)產(chan)生(sheng)懸(xuan)浮(fu)電(dian)位(wei),這(zhe)個(ge)電(dian)位(wei)會(hui)對(dui)地(di)放(fang)電(dian),這(zhe)當(dang)然(ran)是(shi)不(bu)可(ke)能(neng)的(de)。因(yin)此(ci),鐵(tie)芯(xin)及(ji)其(qi)夾(jia)具(ju)必(bi)須(xu)正(zheng)確(que)可(ke)靠(kao)地(di)接(jie)地(di)(除穿心螺栓外)。鐵tie芯xin隻zhi允yun許xu一yi點dian點dian接jie地di。如ru果guo有you兩liang點dian或huo兩liang點dian以yi上shang的de接jie地di,鐵tie芯xin將jiang與yu接jie地di點dian和he地di球qiu形xing成cheng閉bi路lu。變bian壓ya器qi運yun行xing時shi,如ru果guo有you磁ci通tong,會hui穿chuan過guo閉bi路lu,產chan生sheng所suo謂wei的de環huan流liu,導dao致zhi鐵tie芯xin局ju部bu過guo熱re,甚shen至zhi燒shao毀hui金jin屬shu零ling件jian和he絕jue緣yuan層ceng。