利用(yong)原理產生交流(liu)高(gao)(gao)電(dian)(dian)(dian)壓(ya)(ya)的(de)(de)試(shi)驗(yan)裝置。由于應用(yong)高(gao)(gao)電(dian)(dian)(dian)壓(ya)(ya)試(shi)驗(yan)變壓(ya)(ya)器(qi)為大電(dian)(dian)(dian)容(rong)(rong)量的(de)(de)試(shi)品(pin)(如長(chang)電(dian)(dian)(dian)纜(lan)、六氟化硫管道、電(dian)(dian)(dian)容(rong)(rong)器(qi)以及(ji)容(rong)(rong)量很大的(de)(de)發電(dian)(dian)(dian)機)進行(xing)耐壓(ya)(ya)試(shi)驗(yan)時，常發生滿足不(bu)了試(shi)驗(yan)容(rong)(rong)量的(de)(de)問題，且電(dian)(dian)(dian)力系統內進行(xing)上述試(shi)品(pin)的(de)(de)現場耐壓(ya)(ya)試(shi)驗(yan)時，采(cai)用(yong)龐(pang)大的(de)(de)試(shi)驗(yan)變壓(ya)(ya)器(qi)作為電(dian)(dian)(dian)源，運輸(shu)也(ye)很不(bu)方便，為此有時改用(yong)串(chuan)聯諧(xie)振裝置取(qu)代高(gao)(gao)壓(ya)(ya)試(shi)驗(yan)變壓(ya)(ya)器(qi)。

調頻串聯(lian)(lian)諧(xie)振(zhen)(zhen)試(shi)(shi)驗裝置的(de)(de)原理(li)接(jie)線(xian)(xian)如圖(tu)(tu)1所(suo)示(shi)，其中(zhong)T為(wei)(wei)供電(dian)變(bian)壓(ya)(ya)(ya)器;L是(shi)調諧(xie)用可變(bian)電(dian)感;C為(wei)(wei)試(shi)(shi)品、分壓(ya)(ya)(ya)器等(deng)的(de)(de)總電(dian)容;R是(shi)代表(biao)回路中(zhong)實(shi)際存在的(de)(de)引線(xian)(xian)及(ji)調諧(xie)電(dian)感固有的(de)(de)電(dian)阻，也代表(biao)了高(gao)(gao)壓(ya)(ya)(ya)導(dao)線(xian)(xian)的(de)(de)電(dian)暈損耗及(ji)試(shi)(shi)品介質(zhi)損耗的(de)(de)等(deng)值(zhi)(zhi)電(dian)阻，有時也包括(kuo)特地接(jie)入的(de)(de)調整電(dian)阻。工作時調整電(dian)感L的(de)(de)大小，使之與電(dian)容C在工頻之下(xia)發生串聯(lian)(lian)諧(xie)振(zhen)(zhen)。諧(xie)振(zhen)(zhen)的(de)(de)條(tiao)件是(shi)ωL=1/ωC，ω=2πf，f為(wei)(wei)50 Hz或鄰近值(zhi)(zhi)。若Us為(wei)(wei)試(shi)(shi)驗時的(de)(de)高(gao)(gao)壓(ya)(ya)(ya)側電(dian)源電(dian)壓(ya)(ya)(ya)，則諧(xie)振(zhen)(zhen)狀態(tai)下(xia)電(dian)流可達到IM=Us/R。定義品質(zhi)因數Q=ωL/R(一般(ban)Q=20～80)，于是(shi)Uc=UL=IM(ωL)=QUs，所(suo)以(yi)電(dian)源變(bian)壓(ya)(ya)(ya)器所(suo)需的(de)(de)電(dian)壓(ya)(ya)(ya)值(zhi)(zhi)及(ji)容量均(jun)為(wei)(wei)試(shi)(shi)驗所(suo)需值(zhi)(zhi)的(de)(de)1/Q。圖(tu)(tu)2所(suo)示(shi)為(wei)(wei)調感式(shi)串聯(lian)(lian)諧(xie)振(zhen)(zhen)裝置的(de)(de)一種實(shi)際連接(jie)方(fang)式(shi)。

圖1及圖2說明了(le)調(diao)(diao)感(gan)方(fang)(fang)式串(chuan)聯諧(xie)振裝(zhuang)置的(de)基本原(yuan)理(li)，實際上也可用調(diao)(diao)容式或(huo)電源調(diao)(diao)頻式等調(diao)(diao)諧(xie)方(fang)(fang)式。調(diao)(diao)頻串(chuan)聯諧(xie)振試驗(yan)裝(zhuang)置，其頻率(lv)在(zai)45～300Hz的(de)范(fan)圍(wei)內(nei)調(diao)(diao)節，特別適(shi)用于現場氣體絕緣(yuan)變電站設(she)備的(de)耐壓試驗(yan)。這種方(fang)(fang)式有利于Q值(zhi)的(de)提高，并(bing)使裝(zhuang)置重量減(jian)輕。