關鍵字:零磁通互感器,漏電流測量
本ben文wen介jie紹shao了le基ji於yu零ling磁ci通tong互hu感gan器qi原yuan理li測ce量liang微wei弱ruo漏lou電dian流liu的de方fang法fa,證zheng明ming零ling磁ci通tong互hu感gan器qi技ji術shu是shi一yi種zhong高gao可ke靠kao性xing的de技ji術shu,在zai諸zhu如ru變bian壓ya器qi鐵tie芯xin漏lou電dian流liu在zai線xian監jian測ce等deng係xi統tong中zhong得de到dao推tui廣guang和he應ying用yong。
1、引言
suizhewoguozhinengdianwangdefazhan,yuelaiyueduodedianlisheshixuyaonarujiancexitong,qizhongduiyubianyaqileidetiexinjiedixieloudianliudejianceyechengweijiancexitonglibukehuoquedeyibufen。duiyuxiaodianliudejiance,youqishihaoanji(甚至微安級)漏電流來說,常用的互感器、霍爾傳感器、citongmendianliuchuanganqidengdoubuzaishiyong。yinweidianliutaixiao,putongdedianliuchuanganqiwufazhunqueceliang。shiyonggenggaojideruancixingcailiaobirufeijing,chaoweijing,pomohejindenggaocidaolvdecailiao,zaiguoquyizhishitigaohuganqixingnengdebuerfamen,danyiranyudaopingjing。yaoxiangtigaohuganqideceliangjingdu,jianshaobicha,changyongdebanfahaiyouzengjiaxianquandezashu,erzengjiazashudejieguoshihuganqideshuchudianliugengjiaweiruo,congershihoujichulijihuwufaceliang。weilezengdafubiandedianliushuchu,zebixujianshaofuxianquandezashu,erjianxiaozashuyouhuidaozhihuganqidebichahejiaochajijuzengda。zenyangjiejueshangmiandemaodun,duiyuceliangyuanjianchangjiatichuletiaozhan。
大型變壓器,鐵芯接地電流需要被有效監測
2、零磁通互感器工作原理
理想的互感器是原副邊嚴格保持匝比關係,能量無損耗的從副邊輸出。但事實上總有一部分原邊的能量要用於激磁電流Io而消耗掉,這個Io就是誤差的來源。要想減小這個Io,就需要對這個激磁電流進行補償。自從1953年美國的A.Hubson發明雙極性零磁通互感器之後,各國對該技術的研究也大致沿用此路線。其框圖如下: 調整Zp的阻值大小,以確保磁芯I內的磁通為零。
3、零磁通互感器的屏蔽
為了能夠準確的測量微小的電流(比如幾十微安),還(hai)需(xu)要(yao)對(dui)外(wai)界(jie)的(de)幹(gan)擾(rao)進(jin)行(xing)有(you)效(xiao)屏(ping)蔽(bi)。針(zhen)對(dui)電(dian)場(chang)屏(ping)蔽(bi)和(he)電(dian)磁(ci)場(chang)屏(ping)蔽(bi)需(xu)要(yao)分(fen)別(bie)采(cai)取(qu)不(bu)同(tong)的(de)方(fang)法(fa),本(ben)應(ying)用(yong)中(zhong)就(jiu)用(yong)到(dao)了(le)銅(tong)皮(pi)層(ceng),矽(gui)鋼(gang)層(ceng)和(he)坡(po)莫(mo)合(he)金(jin)層(ceng),用(yong)於(yu)對(dui)不(bu)同(tong)類(lei)型(xing)的(de)幹(gan)擾(rao)進(jin)行(xing)屏(ping)蔽(bi),從(cong)而(er)使(shi)輸(shu)出(chu)穩(wen)定(ding)。
零磁通漏電流變送器,LJIB係列,有效監測微安級電流變化
4、零磁通互感器的優缺點
因yin為wei零ling磁ci通tong互hu感gan器qi固gu有you的de高gao精jing度du,以yi及ji可ke以yi測ce量liang微wei弱ruo小xiao電dian流liu的de特te點dian,可ke以yi應ying用yong在zai很hen多duo需xu要yao在zai線xian測ce量liang小xiao電dian流liu的de場chang合he,比bi如ru電dian氣qi設she備bei絕jue緣yuan漏lou電dian流liu的de在zai線xian監jian測ce。基ji於yu該gai技ji術shu可ke以yi製zhi作zuo變bian送song器qi,用yong於yu測ce量liang差cha分fen電dian流liu,並bing使shi其qi輸shu出chu標biao準zhun的de電dian流liu或huo電dian壓ya信xin號hao,如ruDC4-20mA,DC0-5Vdeng。tongshiweilemanzugaojingdudianyaceliangdeyaoqiu,haikeyizuochenglingcitongdianyahuganqi。danshilingcitonghuganqidejiagonggongyifuza,shiyongdangzhongxuyaolianxutiaojiebuchangdianzuyihuodezhenzhengdelingcitong(或微磁通)狀態,實際使用時為了獲得較高精度,還需對外界幹擾進行有效屏蔽,導致其體積較大,成本較高。
5、結束語
lingcitonghuganqiyouyuqijuyoudegaojingduhekeyidizabidetexing,shiqikeyiyingyongzaihenduoduijingduhuoxiaodianliuceliangyouteshuyaoqiudechanghe,shijishangjinnianlailingcitonghuganqiyijingzaidianqijueyuanjiancexitongzhongdedaolelianghaodeyingyong。