利(li)用(yong)(yong)原理產生交流(liu)高電(dian)(dian)壓(ya)的(de)(de)試(shi)(shi)驗(yan)裝(zhuang)置。由(you)于應用(yong)(yong)高電(dian)(dian)壓(ya)試(shi)(shi)驗(yan)變壓(ya)器(qi)(qi)(qi)(qi)為(wei)大電(dian)(dian)容量的(de)(de)試(shi)(shi)品(pin)(pin)(如長電(dian)(dian)纜、六氟化(hua)硫(liu)管道、電(dian)(dian)容器(qi)(qi)(qi)(qi)以及容量很大的(de)(de)發電(dian)(dian)機)進行耐(nai)壓(ya)試(shi)(shi)驗(yan)時(shi)，常發生滿足不了試(shi)(shi)驗(yan)容量的(de)(de)問(wen)題，且(qie)電(dian)(dian)力(li)系統內進行上述試(shi)(shi)品(pin)(pin)的(de)(de)現場(chang)耐(nai)壓(ya)試(shi)(shi)驗(yan)時(shi)，采(cai)用(yong)(yong)龐(pang)大的(de)(de)試(shi)(shi)驗(yan)變壓(ya)器(qi)(qi)(qi)(qi)作為(wei)電(dian)(dian)源，運輸(shu)也很不方(fang)便，為(wei)此有時(shi)改用(yong)(yong)串聯諧振裝(zhuang)置取代(dai)高壓(ya)試(shi)(shi)驗(yan)變壓(ya)器(qi)(qi)(qi)(qi)。
調(diao)頻串(chuan)聯(lian)諧(xie)(xie)振(zhen)試(shi)驗(yan)裝置(zhi)的(de)原(yuan)理接線如圖(tu)1所示(shi)，其中T為(wei)(wei)(wei)供電(dian)(dian)(dian)(dian)變(bian)壓(ya)(ya)(ya)器(qi);L是調(diao)諧(xie)(xie)用可變(bian)電(dian)(dian)(dian)(dian)感;C為(wei)(wei)(wei)試(shi)品、分(fen)壓(ya)(ya)(ya)器(qi)等的(de)總電(dian)(dian)(dian)(dian)容(rong);R是代(dai)表(biao)(biao)回路中實(shi)際(ji)存在(zai)的(de)引線及(ji)調(diao)諧(xie)(xie)電(dian)(dian)(dian)(dian)感固有的(de)電(dian)(dian)(dian)(dian)阻(zu)，也(ye)代(dai)表(biao)(biao)了高壓(ya)(ya)(ya)導(dao)線的(de)電(dian)(dian)(dian)(dian)暈(yun)損(sun)耗(hao)及(ji)試(shi)品介質損(sun)耗(hao)的(de)等值電(dian)(dian)(dian)(dian)阻(zu)，有時也(ye)包括特地接入的(de)調(diao)整(zheng)電(dian)(dian)(dian)(dian)阻(zu)。工作時調(diao)整(zheng)電(dian)(dian)(dian)(dian)感L的(de)大小，使之與電(dian)(dian)(dian)(dian)容(rong)C在(zai)工頻之下(xia)發生串(chuan)聯(lian)諧(xie)(xie)振(zhen)。諧(xie)(xie)振(zhen)的(de)條(tiao)件是ωL=1/ωC，ω=2πf，f為(wei)(wei)(wei)50 Hz或鄰近值。若Us為(wei)(wei)(wei)試(shi)驗(yan)時的(de)高壓(ya)(ya)(ya)側電(dian)(dian)(dian)(dian)源(yuan)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)，則諧(xie)(xie)振(zhen)狀態下(xia)電(dian)(dian)(dian)(dian)流可達到(dao)IM=Us/R。定義(yi)品質因數Q=ωL/R(一般Q=20～80)，于是Uc=UL=IM(ωL)=QUs，所以電(dian)(dian)(dian)(dian)源(yuan)變(bian)壓(ya)(ya)(ya)器(qi)所需(xu)(xu)的(de)電(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)值及(ji)容(rong)量均為(wei)(wei)(wei)試(shi)驗(yan)所需(xu)(xu)值的(de)1/Q。圖(tu)2所示(shi)為(wei)(wei)(wei)調(diao)感式串(chuan)聯(lian)諧(xie)(xie)振(zhen)裝置(zhi)的(de)一種(zhong)實(shi)際(ji)連接方式。
圖(tu)(tu)1及圖(tu)(tu)2說明了(le)調(diao)感(gan)方(fang)式串(chuan)聯諧(xie)振裝(zhuang)置(zhi)(zhi)的(de)基本原理，實(shi)際上也可用(yong)(yong)調(diao)容(rong)式或電(dian)源(yuan)調(diao)頻(pin)(pin)式等調(diao)諧(xie)方(fang)式。調(diao)頻(pin)(pin)串(chuan)聯諧(xie)振試驗裝(zhuang)置(zhi)(zhi)，其頻(pin)(pin)率在45～300Hz的(de)范(fan)圍內調(diao)節，特(te)別適用(yong)(yong)于現場氣體絕緣變電(dian)站設(she)備的(de)耐壓試驗。這種(zhong)方(fang)式有利于Q值(zhi)的(de)提(ti)高，并(bing)使裝(zhuang)置(zhi)(zhi)重量(liang)減輕。
