一.零序保護定義

 

在大短路電流接地係統中發生接地故障後，就有零序電流、零序電壓和零序功率出現
，利用這些電氣量構成保護接地短路的繼電保護裝置統稱為零序保護。

 

 

三相電流平衡時
，沒有零序電流，不平衡時產生零序電流，零序保護就是用零序互感器采集零序電流，當零序電流超過一定值（綜合保護中設定）
，綜合保護接觸器吸合，斷開電路。零序電流互感器內穿過三根相線矢量。

 

正常情況下，三根線的向量和為零，零序電流互感器無零序電流。當人體觸電或者其他漏電情況下：三根線的向量和不為零
，零序電流互感器有零序電流
，一旦達到設定值
，則保護動作跳閘。

 

 

 

 

若不止一台變壓器時
，運行方式往往隻允許1-2台(tai)接(jie)地(di)運(yun)行(xing)
，設(she)計(ji)采(cai)用(yong)中(zhong)性(xing)點(dian)零(ling)序(xu)電(dian)流(liu)繼(ji)電(dian)器(qi)與(yu)經(jing)相(xiang)鄰(lin)變(bian)壓(ya)器(qi)中(zhong)性(xing)點(dian)零(ling)序(xu)電(dian)流(liu)繼(ji)電(dian)器(qi)控(kong)製(zhi)的(de)零(ling)序(xu)電(dian)壓(ya)繼(ji)電(dian)器(qi)配(pei)合(he)使(shi)用(yong)的(de)變(bian)壓(ya)器(qi)保(bao)護(hu)方(fang)案(an)
，保(bao)護(hu)回(hui)路(lu)設(she)計(ji)先(xian)跳(tiao)中(zhong)性(xing)點(dian)不(bu)接(jie)地(di)變(bian)壓(ya)器(qi)，然(ran)後(hou)中(zhong)性(xing)點(dian)跳(tiao)直(zhi)接(jie)接(jie)地(di)的(de)變(bian)壓(ya)器(qi)
，以(yi)防(fang)止(zhi)不(bu)接(jie)地(di)係(xi)統(tong)故(gu)障(zhang)點(dian)的(de)間(jian)歇(xie)性(xing)弧(hu)光(guang)過(guo)電(dian)壓(ya)危(wei)及(ji)電(dian)氣(qi)設(she)備(bei)的(de)安(an)全(quan)。為(wei)避(bi)免(mian)全(quan)廠(chang)所(suo)有(you)變(bian)壓(ya)器(qi)全(quan)部(bu)被(bei)切(qie)的(de)嚴(yan)重(zhong)後(hou)果(guo)
，保(bao)護(hu)時(shi)間(jian)應(ying)逐(zhu)級(ji)配(pei)合(he)，先(xian)斷(duan)開(kai)母(mu)聯(lian)或(huo)分(fen)斷(duan)路(lu)器(qi)
，再(zai)經(jing)零(ling)序(xu)電(dian)壓(ya)元(yuan)件(jian)跳(tiao)開(kai)中(zhong)心(xin)點(dian)不(bu)接(jie)地(di)主(zhu)變(bian)，最(zui)後(hou)經(jing)零(ling)序(xu)電(dian)流(liu)元(yuan)件(jian)跳(tiao)開(kai)中(zhong)性(xing)點(dian)接(jie)地(di)主(zhu)變(bian)。

 

 

對dui中zhong性xing點dian有you可ke能neng直zhi接jie接jie地di運yun行xing
，也ye有you可ke能neng不bu接jie地di運yun行xing的de主zhu變bian，因yin失shi去qu接jie地di中zhong性xing點dian引yin起qi的de電dian壓ya升sheng高gao
，應ying裝zhuang設she相xiang應ying的de保bao護hu裝zhuang置zhi。在zai直zhi接jie接jie地di時shi用yong零ling序xu電dian流liu保bao護hu。在zai中zhong性xing點dian不bu接jie地di時shi用yong零ling序xu電dian壓ya保bao護hu或huo裝zhuang設she放fang電dian間jian隙xi保bao護hu
，放fang到dao間jian隙xi保bao護hu起qi到dao過guo電dian壓ya保bao護hu的de作zuo用yong
，當dang放fang電dian間jian隙xi被bei擊ji穿chuan形xing成cheng零ling序xu電dian流liu通tong路lu時shi，利li用yong接jie在zai放fang電dian間jian隙xi回hui路lu的de零ling序xu電dian流liu保bao護hu，切qie除chu該gai變bian壓ya器qi。變bian壓ya器qi采cai用yong放fang電dian間jian隙xi保bao護hu，放fang電dian間jian隙xi裝zhuang於yu變bian壓ya器qi中zhong性xing點dian與yu地di線xian之zhi間jian、有棒形、球形、角(jiao)形(xing)等(deng)多(duo)種(zhong)形(xing)式(shi)
，實(shi)際(ji)安(an)裝(zhuang)中(zhong)可(ke)以(yi)棒(bang)形(xing)用(yong)得(de)最(zui)多(duo)
，零(ling)序(xu)電(dian)壓(ya)保(bao)護(hu)動(dong)作(zuo)電(dian)壓(ya)按(an)發(fa)生(sheng)單(dan)相(xiang)接(jie)地(di)故(gu)障(zhang)時(shi)保(bao)護(hu)安(an)裝(zhuang)處(chu)可(ke)能(neng)出(chu)現(xian)最(zui)大(da)零(ling)序(xu)電(dian)壓(ya)整(zheng)定(ding)。

 

 

對變壓器高壓側中性點直接接地的自耦變壓器和三繞組變壓器采用零序過電流保護，取自變壓器中性點的零序CT安裝無方向零序保護
，在主變兩側分別裝上零序保護，了為滿足選擇性可增設零序方向元件。方向元件用各斷路器側CTdezichanlingxudianliu。zhubianzhongxingdianlingxudianliuhuganqidejixingjiexiankeyijiangzhongxingdianlingxudianliubaohuzhixiangbencemuxianhuozhubiance。caiyongduanluqichudelingxudianliubaohu，heyibangaozhongyacefangxiangzhixianggezidemuxian，dandangzhongyacebuwuyuanshi

，gaoyacelingxufangxiangkezhixiangzhubian。zhixiangmuxianbaohudefanweiyiweiduanluqidianliuhuganqianzhuangchukaishi
，xuyaoyuxianlulingxubaohupeihe。zhixiangzhubianbianyaqi
，xuyaozhubianyaqilingyicechuxiandejiedibaohuxiangpeihe。caiyongzhubianzhongxingdianchudilingxudianliubaohu
，zebaohufanweibiduanluqichulingxudianliubaohubiyaokuanyixie。xiaolangdimuqianyunxingdezhubianzhongxingdianlingxudianliubaohuwufangxiang，zheyangdezhengdingpeihebijiaoqingxifangbian，yishixianzhitiaokaimulianduanluqi，ershixianzhitiaokaibencekaiguan。