配電變壓器(qi)保護(hu)措施研究

變壓(ya)器運行是(shi)否正常(chang)直接影(ying)響用(yong)戶(hu)生產和生活用(yong)電(dian)，并關系到用(yong)電(dian)設(she)備的安全。為了保證(zheng)用(yong)戶(hu)用(yong)上(shang)優質、安全電(dian)，必(bi)須保證(zheng)配(pei)電(dian)變壓(ya)器運行正常(chang)，本文詳細論述了在日(ri)常(chang)使用(yong)中配(pei)電(dian)變壓(ya)器的保護措施及其注意事(shi)項。

配(pei)(pei)電(dian)(dian)(dian)變(bian)(bian)壓(ya)器(qi)(qi)是配(pei)(pei)電(dian)(dian)(dian)系統中根據電(dian)(dian)(dian)磁感應定律(lv)變(bian)(bian)換交流電(dian)(dian)(dian)壓(ya)和電(dian)(dian)(dian)流而傳輸交流電(dian)(dian)(dian)能的(de)一(yi)種靜止電(dian)(dian)(dian)器(qi)(qi)。通(tong)常(chang)(chang)安(an)裝在電(dian)(dian)(dian)線桿、臺架(jia)或配(pei)(pei)電(dian)(dian)(dian)所中，一(yi)般將6-10千(qian)伏電(dian)(dian)(dian)壓(ya)降至(zhi)400伏左(zuo)右(you)輸入用戶。所以我們有必要(yao)從保(bao)護配(pei)(pei)置技術角度和日常(chang)(chang)運(yun)(yun)行管理兩大(da)方面來談談配(pei)(pei)電(dian)(dian)(dian)變(bian)(bian)壓(ya)器(qi)(qi)的(de)保(bao)護措(cuo)施及其注意事項，以保(bao)證配(pei)(pei)電(dian)(dian)(dian)變(bian)(bian)壓(ya)器(qi)(qi)正常(chang)(chang)運(yun)(yun)行，保(bao)證用戶安(an)全用電(dian)(dian)(dian)。

1保護配置技術方(fang)面

1.1裝設避雷器保(bao)護，防止雷擊過(guo)電(dian)壓

配(pei)(pei)電變(bian)壓器(qi)是配(pei)(pei)電網中(zhong)(zhong)十分(fen)重(zhong)要的設(she)備，一(yi)旦發生雷擊損壞事故(gu)，就(jiu)會造成停電，直接影響(xiang)著(zhu)工農業生產和人民生活。因此，在條件許可時，好采用(yong)(yong)避雷器(qi)來保護(hu)，在中(zhong)(zhong)性點(dian)不(bu)接地的系(xi)統(tong)中(zhong)(zhong)，也可采用(yong)(yong)兩相閥型(xing)避雷器(qi)—相保護(hu)間隙的保護(hu)方式。但同一(yi)配(pei)(pei)電網絡中(zhong)(zhong)，所(suo)有間隙必須裝在同一(yi)相導線上，這樣既可以(yi)節省一(yi)只閥型(xing)避雷器(qi)，而同時又(you)不(bu)至于增加(jia)線路跳閘的次數。

保護變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)的(de)閥(fa)型(xing)(xing)避(bi)(bi)雷(lei)(lei)器(qi)(qi)(qi)(qi)、管型(xing)(xing)避(bi)(bi)雷(lei)(lei)器(qi)(qi)(qi)(qi)或保護間(jian)隙，要求盡量靠近(jin)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)安裝(zhuang)，距離越(yue)近(jin)保護效果越(yue)好(hao)，一般都(dou)要求裝(zhuang)在(zai)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)高(gao)壓(ya)(ya)(ya)(ya)側熔斷(duan)器(qi)(qi)(qi)(qi)內側。其接地(di)(di)(di)線(xian)，應和(he)配電(dian)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)的(de)金屬外(wai)殼和(he)低(di)(di)壓(ya)(ya)(ya)(ya)側中性(xing)點連(lian)在(zai)一起(qi)共同(tong)接地(di)(di)(di)。當(dang)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)容量為100kY˙A及以(yi)上時(shi)(shi)，接地(di)(di)(di)電(dian)阻(zu)應盡可能降低(di)(di)到4Ω以(yi)下；當(dang)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)容量小于100kV˙A時(shi)(shi)，接地(di)(di)(di)電(dian)阻(zu)10Ω及以(yi)下即可。當(dang)這—二(er)點連(lian)在(zai)一起(qi)，高(gao)壓(ya)(ya)(ya)(ya)側落(luo)雷(lei)(lei)，避(bi)(bi)雷(lei)(lei)器(qi)(qi)(qi)(qi)或間(jian)隙放(fang)電(dian)時(shi)(shi)，變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)絕緣(yuan)所(suo)承受(shou)的(de)即是閥(fa)型(xing)(xing)避(bi)(bi)雷(lei)(lei)器(qi)(qi)(qi)(qi)的(de)殘壓(ya)(ya)(ya)(ya)，而接地(di)(di)(di)裝(zhuang)置上的(de)電(dian)壓(ya)(ya)(ya)(ya)降并沒有作用(yong)在(zai)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)的(de)絕緣(yuan)上，這樣對(dui)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)保護是很有利的(de)，能降低(di)(di)高(gao)、低(di)(di)壓(ya)(ya)(ya)(ya)繞組間(jian)和(he)高(gao)壓(ya)(ya)(ya)(ya)繞組對(dui)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)鐵心與外(wai)殼之間(jian)發(fa)生絕緣(yuan)擊(ji)穿的(de)危險(xian)。但是為了防止(zhi)變(bian)(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)低(di)(di)壓(ya)(ya)(ya)(ya)側中性(xing)點電(dian)位瞬時(shi)(shi)升高(gao)對(dui)用(yong)戶(hu)安全(quan)的(de)影響，可以(yi)在(zai)靠近(jin)用(yong)戶(hu)的(de)地(di)(di)(di)方加裝(zhuang)輔助接地(di)(di)(di)線(xian)。

配電(dian)變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)可(ke)能出(chu)現(xian)的(de)(de)(de)過電(dian)壓(ya)(ya)(ya)(ya)(ya)分兩(liang)種情況：（1）正變(bian)(bian)換：當(dang)(dang)雷(lei)電(dian)波到達Y，y接線(xian)的(de)(de)(de)變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)的(de)(de)(de)低壓(ya)(ya)(ya)(ya)(ya)繞組時(shi)，中性(xing)點(dian)所(suo)裝的(de)(de)(de)擊(ji)(ji)穿保(bao)險(xian)被擊(ji)(ji)穿，或(huo)當(dang)(dang)雷(lei)電(dian)波到達Y，Yn接線(xian)的(de)(de)(de)變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)低壓(ya)(ya)(ya)(ya)(ya)繞組時(shi)，都(dou)會(hui)在(zai)外加(jia)電(dian)壓(ya)(ya)(ya)(ya)(ya)作用下，通(tong)過變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)的(de)(de)(de)低壓(ya)(ya)(ya)(ya)(ya)繞組的(de)(de)(de)沖擊(ji)(ji)電(dian)流按變(bian)(bian)比感(gan)應出(chu)電(dian)動勢，而(er)使高壓(ya)(ya)(ya)(ya)(ya)繞組的(de)(de)(de)中性(xing)點(dian)電(dian)壓(ya)(ya)(ya)(ya)(ya)升高。（2）反變(bian)(bian)換：當(dang)(dang)10kY側遭受雷(lei)擊(ji)(ji)時(shi)，經(jing)過避(bi)雷(lei)器(qi)(qi)(qi)會(hui)有(you)較(jiao)大的(de)(de)(de)雷(lei)電(dian)流通(tong)過，在(zai)接地裝置上產生(sheng)電(dian)壓(ya)(ya)(ya)(ya)(ya)降(jiang)，這個電(dian)壓(ya)(ya)(ya)(ya)(ya)降(jiang)同時(shi)將作用在(zai)低壓(ya)(ya)(ya)(ya)(ya)繞組的(de)(de)(de)中性(xing)點(dian)并(bing)加(jia)到低壓(ya)(ya)(ya)(ya)(ya)繞組上，通(tong)過電(dian)磁感(gan)應也(ye)會(hui)在(zai)高壓(ya)(ya)(ya)(ya)(ya)側出(chu)現(xian)高電(dian)壓(ya)(ya)(ya)(ya)(ya)，對于星形接線(xian)的(de)(de)(de)變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)，高壓(ya)(ya)(ya)(ya)(ya)側中性(xing)點(dian)上也(ye)會(hui)出(chu)現(xian)對絕緣有(you)危(wei)險(xian)的(de)(de)(de)高電(dian)壓(ya)(ya)(ya)(ya)(ya)。另外也(ye)可(ke)根據具體情況在(zai)變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)低壓(ya)(ya)(ya)(ya)(ya)側加(jia)裝避(bi)雷(lei)器(qi)(qi)(qi)或(huo)擊(ji)(ji)穿保(bao)險(xian)器(qi)(qi)(qi)，能進一步提高變(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)安全(quan)可(ke)靠性(xing)。

運(yun)(yun)行(xing)經驗證明，處在多雷(lei)地(di)區的(de)(de)配電(dian)(dian)變(bian)壓(ya)(ya)器(qi)(qi)(qi)，雖然裝了閥(fa)型避(bi)(bi)雷(lei)器(qi)(qi)(qi)保護，但因雷(lei)擊(ji)引起(qi)損壞者仍然不少(shao)，，根據事(shi)故教(jiao)訓，為了減少(shao)配電(dian)(dian)變(bian)壓(ya)(ya)器(qi)(qi)(qi)事(shi)故，還應(ying)根據具體情況采取(qu)下(xia)列(lie)技術(shu)措施：（1）消除配電(dian)(dian)變(bian)壓(ya)(ya)器(qi)(qi)(qi)本身的(de)(de)絕(jue)緣(yuan)(yuan)(yuan)薄弱點(dian)。在運(yun)(yun)行(xing)葉，還應(ying)加強對(dui)變(bian)壓(ya)(ya)器(qi)(qi)(qi)絕(jue)緣(yuan)(yuan)(yuan)油(you)的(de)(de)試驗和(he)(he)分析，因絕(jue)緣(yuan)(yuan)(yuan)油(you)劣化會直接導(dao)致繞(rao)組(zu)絕(jue)緣(yuan)(yuan)(yuan)的(de)(de)降(jiang)(jiang)低(di)，所以發現問題后必須及時(shi)進(jin)行(xing)處理或更換。對(dui)配電(dian)(dian)變(bian)壓(ya)(ya)器(qi)(qi)(qi)進(jin)行(xing)廣泛的(de)(de)沖(chong)擊(ji)試驗和(he)(he)匝(za)間試驗，能(neng)有效(xiao)地(di)發現變(bian)壓(ya)(ya)器(qi)(qi)(qi)上存(cun)在的(de)(de)絕(jue)緣(yuan)(yuan)(yuan)弱點(dian)，及時(shi)安排檢修，能(neng)減少(shao)雷(lei)擊(ji)損壞事(shi)故，（2）裝在木桿線(xian)路上的(de)(de)配電(dian)(dian)變(bian)壓(ya)(ya)器(qi)(qi)(qi)，可在變(bian)壓(ya)(ya)器(qi)(qi)(qi)進(jin)線(xian)段內裝設保護間隙，或將導(dao)線(xian)為三角排列(lie)的(de)(de)頂相(xiang)絕(jue)緣(yuan)(yuan)(yuan)子的(de)(de)鐵腳接地(di)，以降(jiang)(jiang)低(di)雷(lei)電(dian)(dian)侵(qin)入波的(de)(de)陡度和(he)(he)減少(shao)流(liu)過閥(fa)型避(bi)(bi)雷(lei)器(qi)(qi)(qi)的(de)(de)電(dian)(dian)流(liu)。（3）也可考慮(lv)在配電(dian)(dian)變(bian)壓(ya)(ya)器(qi)(qi)(qi)與閥(fa)型避(bi)(bi)雷(lei)器(qi)(qi)(qi)之(zhi)間，加裝一組(zu)電(dian)(dian)感線(xian)圈(quan)（30匝(za)左右，長24cm，直徑20cm，電(dian)(dian)感值約為100μH），以限(xian)制(zhi)雷(lei)電(dian)(dian)侵(qin)入波的(de)(de)陡度，從(cong)而降(jiang)(jiang)低(di)變(bian)壓(ya)(ya)器(qi)(qi)(qi)繞(rao)組(zu)層間絕(jue)緣(yuan)(yuan)(yuan)上的(de)(de)過電(dian)(dian)壓(ya)(ya)。