繼電保護二次回路干擾源

在(zai)發電(dian)廠電(dian)力系統(tong)中，繼電(dian)保護二(er)次(ci)回(hui)(hui)(hui)路(lu)(lu)是(shi)較為重要的(de)保護控制回(hui)(hui)(hui)路(lu)(lu)之一(yi)，在(zai)電(dian)力系統(tong)出(chu)現故障和(he)問題時進行緊急制動可以很(hen)好(hao)地(di)保證系統(tong)的(de)正(zheng)常運行與穩(wen)定。但(dan)近年來我國(guo)電(dian)網(wang)進行了多次(ci)改造和(he)升級，電(dian)力負荷不斷(duan)攀(pan)升，使得整(zheng)個二(er)次(ci)回(hui)(hui)(hui)路(lu)(lu)處(chu)在(zai)一(yi)次(ci)回(hui)(hui)(hui)路(lu)(lu)較大的(de)電(dian)磁場之中，導(dao)致二(er)次(ci)回(hui)(hui)(hui)路(lu)(lu)在(zai)正(zheng)常工作時發生誤動作或(huo)不動作，對電(dian)網(wang)系統(tong)產生極為嚴(yan)重的(de)危害。

對國內(nei)各發電廠進行研究與分析發現，目前在繼電保護二(er)次(ci)回(hui)路中產(chan)(chan)生(sheng)干(gan)(gan)(gan)擾的(de)干(gan)(gan)(gan)擾源主要包括(kuo)電力系統(tong)本身(shen)運行產(chan)(chan)生(sheng)的(de)強磁場(chang)(chang)(chang)、雷擊、周邊環境人類活動產(chan)(chan)生(sheng)的(de)磁場(chang)(chang)(chang)干(gan)(gan)(gan)擾等。除此之外，人員操作失(shi)誤帶來的(de)電力系統(tong)瞬時(shi)電流、電壓波動，也可能使二(er)次(ci)回(hui)路由(you)于受到不同磁場(chang)(chang)(chang)的(de)干(gan)(gan)(gan)擾而產(chan)(chan)生(sheng)誤動作。

繼電保護二次回路抗干擾措施

在系統正常運行時(shi)，各干(gan)(gan)擾(rao)源對二(er)次回路產生影響(xiang)和(he)干(gan)(gan)擾(rao)的(de)方式(shi)主要(yao)有(you)靜(jing)電(dian)(dian)藕合、電(dian)(dian)磁(ci)感應(ying)、電(dian)(dian)位差等，其實(shi)質(zhi)是以電(dian)(dian)場(chang)、磁(ci)場(chang)的(de)形(xing)式(shi)將干(gan)(gan)擾(rao)能量擴(kuo)散(san)到正常運行的(de)二(er)次回路上。因(yin)此，實(shi)際的(de)抗干(gan)(gan)擾(rao)措施，主要(yao)應(ying)從電(dian)(dian)場(chang)屏蔽、磁(ci)場(chang)屏蔽等方面人(ren)手，主要(yao)包括：

01、繼電保護二次回路對周邊電場磁場的屏蔽

需要(yao)屏(ping)(ping)蔽的(de)(de)干(gan)(gan)擾源(yuan)主要(yao)是(shi)系 次(ci)(ci)回(hui)(hui)(hui)路電(dian)(dian)(dian)流、電(dian)(dian)(dian)壓的(de)(de)波動，其會(hui)造(zao)成周(zhou)邊(bian)磁(ci)場、電(dian)(dian)(dian)場大(da)范圍(wei)變化，從而干(gan)(gan)擾繼(ji)(ji)電(dian)(dian)(dian)保(bao)(bao)護二次(ci)(ci)回(hui)(hui)(hui)路的(de)(de)正常動作。除此(ci)之(zhi)外，還應(ying)有(you)(you)效地(di)避免(mian)(mian)來自于周(zhou)邊(bian)環境中(zhong)強磁(ci)場或強電(dian)(dian)(dian)場對繼(ji)(ji)電(dian)(dian)(dian)保(bao)(bao)護室內(nei)二次(ci)(ci)回(hui)(hui)(hui)路的(de)(de)干(gan)(gan)擾。特(te)別是(shi)繼(ji)(ji)電(dian)(dian)(dian)保(bao)(bao)護室被一次(ci)(ci)線路跨越的(de)(de)情況下，更需要(yao)對其進行特(te)別的(de)(de)屏(ping)(ping)蔽防護。 *好(hao)的(de)(de)屏(ping)(ping)蔽方(fang)式是(shi)金屬屏(ping)(ping)蔽，即在繼(ji)(ji)電(dian)(dian)(dian)保(bao)(bao)護室建設修筑(zhu)時(shi)用鋼板或鋼絲網嵌(qian)人繼(ji)(ji)電(dian)(dian)(dian)保(bao)(bao)護室墻體中(zhong)，并與地(di)面可(ke)靠連(lian)接，在裝上避雷(lei)設施后便(bian)可(ke)以對一次(ci)(ci)回(hui)(hui)(hui)路產生的(de)(de)強磁(ci)場與強電(dian)(dian)(dian)場進行屏(ping)(ping)蔽，同時(shi)可(ke)有(you)(you)效避免(mian)(mian)雷(lei)擊對二次(ci)(ci)回(hui)(hui)(hui)路的(de)(de)損壞。

02、線圈并聯消弧回路

在(zai)(zai)繼電(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護(hu)(hu)器(qi)動作(zuo)的(de)(de)(de)過(guo)(guo)程中(zhong)，瞬(shun)(shun)時的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)流通過(guo)(guo)會在(zai)(zai)線(xian)圈(quan)(quan)內產(chan)(chan)生一個瞬(shun)(shun)時的(de)(de)(de)較大(da)(da)(da)的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)磁感(gan)(gan)(gan)應(ying)(ying)場，其(qi)場蘊含著極大(da)(da)(da)的(de)(de)(de)能量，極容(rong)易在(zai)(zai)突(tu)然的(de)(de)(de)動作(zuo)過(guo)(guo)程中(zhong)產(chan)(chan)生對繼電(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護(hu)(hu)二次回(hui)路(lu)(lu)(lu)的(de)(de)(de)過(guo)(guo)流損傷(shang)，這在(zai)(zai)高(gao)壓(ya)配(pei)電(dian)(dian)(dian)(dian)(dian)線(xian)路(lu)(lu)(lu)中(zhong)表現得(de) *為明顯。對這種自(zi)身產(chan)(chan)生的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)磁場干(gan)擾的(de)(de)(de)控(kong)制(zhi)，可(ke)以采取中(zhong)間繼電(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護(hu)(hu)線(xian)圈(quan)(quan)并(bing)聯消弧回(hui)路(lu)(lu)(lu)的(de)(de)(de)方法。如電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)與線(xian)圈(quan)(quan)并(bing)聯，突(tu)然動作(zuo)時，其(qi)自(zi)身產(chan)(chan)生的(de)(de)(de)較強(qiang)的(de)(de)(de)感(gan)(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)(dian)(dian)會在(zai)(zai)回(hui)路(lu)(lu)(lu)電(dian)(dian)(dian)(dian)(dian)容(rong)的(de)(de)(de)作(zuo)用下(xia)(xia)進行充(chong)電(dian)(dian)(dian)(dian)(dian)，從而(er)極大(da)(da)(da)地減小瞬(shun)(shun)時感(gan)(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)(dian)(dian)流對控(kong)制(zhi)線(xian)圈(quan)(quan)的(de)(de)(de)沖擊和(he)影響(xiang)。又如，利用反(fan)(fan)向二極管(guan)與線(xian)圈(quan)(quan)并(bing)聯。沿著線(xian)路(lu)(lu)(lu)出現的(de)(de)(de)感(gan)(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)(dian)(dian)流在(zai)(zai)回(hui)路(lu)(lu)(lu)中(zhong)反(fan)(fan)向二極管(guan)的(de)(de)(de)作(zuo)用下(xia)(xia)會受到(dao)(dao)抑制(zhi)，從而(er)使控(kong)制(zhi)線(xian)路(lu)(lu)(lu)中(zhong)不會出現過(guo)(guo)高(gao)的(de)(de)(de)動作(zuo)感(gan)(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)(dian)(dian)流，保(bao)(bao)護(hu)(hu)了繼電(dian)(dian)(dian)(dian)(dian)保(bao)(bao)護(hu)(hu)器(qi)的(de)(de)(de)線(xian)圈(quan)(quan)。但突(tu)然動作(zuo)帶來的(de)(de)(de)瞬(shun)(shun)時感(gan)(gan)(gan)應(ying)(ying)電(dian)(dian)(dian)(dian)(dian)壓(ya)或(huo)電(dian)(dian)(dian)(dian)(dian)流往(wang)往(wang)較大(da)(da)(da)，如果只是(shi)單純地接(jie)(jie)人電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)或(huo)反(fan)(fan)向二極管(guan)到(dao)(dao)系統中(zhong)，瞬(shun)(shun)時高(gao)壓(ya)和(he)強(qiang)電(dian)(dian)(dian)(dian)(dian)流容(rong)易擊穿電(dian)(dian)(dian)(dian)(dian)容(rong)形成短接(jie)(jie)，可(ke)以在(zai)(zai)電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)或(huo)反(fan)(fan)向二極管(guan)上串聯上一個定(ding)值電(dian)(dian)(dian)(dian)(dian)阻(zu)(為了更好地實現對電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)或(huo)反(fan)(fan)向二極管(guan)的(de)(de)(de)保(bao)(bao)護(hu)(hu)，電(dian)(dian)(dian)(dian)(dian)阻(zu)的(de)(de)(de)阻(zu)值應(ying)(ying)根(gen)據電(dian)(dian)(dian)(dian)(dian)網電(dian)(dian)(dian)(dian)(dian)力等級確定(ding))來進行控(kong)制(zhi)。

03、等電位的構建

外界電(dian)(dian)(dian)場、磁場干擾(rao)的消除是保(bao)(bao)護(hu)(hu)二次回路不受干擾(rao)的關(guan)鍵。對于(yu)二次回路周邊的電(dian)(dian)(dian)力(li)系統，其(qi)電(dian)(dian)(dian)纜(lan)電(dian)(dian)(dian)位差的存(cun)在勢必使得該(gai)空間(jian)區(qu)(qu)域內存(cun)在較大的電(dian)(dian)(dian)場，該(gai)電(dian)(dian)(dian)場的消除可以(yi)簡(jian)單地利用等(deng)(deng)電(dian)(dian)(dian)位電(dian)(dian)(dian)纜(lan)的方(fang)法實現。具體的做(zuo)法是在發(fa)(fa)電(dian)(dian)(dian)廠(chang)的接(jie)電(dian)(dian)(dian)箱和(he)繼電(dian)(dian)(dian)保(bao)(bao)護(hu)(hu)室周邊區(qu)(qu)域的電(dian)(dian)(dian)纜(lan)設置(zhi)中選擇(ze)等(deng)(deng)電(dian)(dian)(dian)位布置(zhi)方(fang)式(shi)，如某發(fa)(fa)電(dian)(dian)(dian)廠(chang)選擇(ze)數條100mm2銅排按照機柜屏蔽(bi)布置(zhi)的方(fang)向進(jin)行(xing)設置(zhi)，首尾端(duan)用電(dian)(dian)(dian)纜(lan)連接(jie)，從而形成保(bao)(bao)護(hu)(hu)室內電(dian)(dian)(dian)力(li)系統的等(deng)(deng)電(dian)(dian)(dian)位接(jie)地網(wang)。這種方(fang)式(shi)可以(yi)有效(xiao)地降低發(fa)(fa)生(sheng)故障時各點之間(jian)的地電(dian)(dian)(dian)位差，并能夠(gou)很好地防止電(dian)(dian)(dian)流(liu)燒毀(hui)電(dian)(dian)(dian)纜(lan)屏蔽(bi)層。

04、二次回路與周邊干擾的距離控制

對于比較重要(yao)和(he)關(guan)鍵的(de)(de)(de)二(er)次(ci)回路(lu)，較為(wei)簡便的(de)(de)(de)抗干擾措(cuo)施是用(yong)物理隔離(li)的(de)(de)(de)方式對其與(yu)(yu)主要(yao)干擾源的(de)(de)(de)距(ju)離(li)進行控(kong)(kong)制，以(yi)消(xiao)除周邊電(dian)力系統電(dian)場、磁(ci)場對二(er)次(ci)回路(lu)動作的(de)(de)(de)影響。如某發電(dian)廠將(jiang)二(er)次(ci)回路(lu)機(ji)柜與(yu)(yu)一次(ci)回路(lu)和(he)其他(ta)重大(da)機(ji)組的(de)(de)(de)距(ju)離(li)拉開，并且將(jiang)控(kong)(kong)制電(dian)纜(lan)與(yu)(yu)母線(xian)的(de)(de)(de)距(ju)離(li)拉開，垂直布置，在實際的(de)(de)(de)使用(yong)中(zhong)取得了(le)不錯的(de)(de)(de)效果，大(da)大(da)降低了(le)一次(ci)回路(lu)的(de)(de)(de)電(dian)磁(ci)干擾。

05、屏蔽電纜的使用

在二次(ci)回路(lu)抗干(gan)擾方(fang)面，屏(ping)蔽(bi)電(dian)(dian)(dian)纜(lan)的(de)(de)使(shi)用可(ke)以取得很好的(de)(de)效果。但要注意的(de)(de)是，如果動力線等(deng)強電(dian)(dian)(dian)線路(lu)與繼電(dian)(dian)(dian)保護(hu)二次(ci)回路(lu)共用電(dian)(dian)(dian)纜(lan)，極有可(ke)能導致二次(ci)回路(lu)受到一次(ci)回路(lu)的(de)(de)電(dian)(dian)(dian)流作用而燒(shao)毀。另(ling)外(wai)，相電(dian)(dian)(dian)壓(ya)、電(dian)(dian)(dian)流線和其中性(xing)線應該分別置于(yu)同(tong)一電(dian)(dian)(dian)纜(lan)內，從而減小信號回路(lu)包圍空(kong)間變化磁通的(de)(de)面積，降(jiang)低磁感應干(gan)擾，在電(dian)(dian)(dian)纜(lan)安裝敷設過程中應避免互借(jie)電(dian)(dian)(dian)纜(lan)備用芯的(de)(de)情況，否則對(dui)于(yu)電(dian)(dian)(dian)纜(lan)的(de)(de)屏(ping)蔽(bi)效果極為不利。