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隨著國民經濟(ji)的不斷(duan)發展和(he)電力系統(tong)的不斷(duan)完(wan)善，電力系統(tong)的安(an)全運行(xing)及供電的可靠性顯得越來越重要(yao)。

傳統觀念認為:3~35kV(含66kV)電(dian)(dian)網屬于中(zhong)低壓(ya)的(de)(de)變壓(ya)配電(dian)(dian)網，此類(lei)電(dian)(dian)網中(zhong)的(de)(de)內部(bu)過電(dian)(dian)壓(ya)的(de)(de)值(zhi)不(bu)高，所以(yi)(yi)危及電(dian)(dian)網絕(jue)緣安全水平的(de)(de)主要(yao)因(yin)(yin)素(su)不(bu)是(shi)(shi)內部(bu)過電(dian)(dian)壓(ya)，而(er)(er)是(shi)(shi)大氣(qi)過電(dian)(dian)壓(ya)（即雷電(dian)(dian)過電(dian)(dian)壓(ya)），因(yin)(yin)而(er)(er)長期以(yi)(yi)來采取的(de)(de)過電(dian)(dian)壓(ya)保護措施(shi)僅(jin)是(shi)(shi)以(yi)(yi)防止(zhi)大氣(qi)過電(dian)(dian)壓(ya)對設(she)備的(de)(de)侵(qin)(qin)害。主要(yao)技術措施(shi)僅(jin)限于裝設(she)各類(lei)避雷器(qi)(qi)，避雷器(qi)(qi)的(de)(de)放(fang)電(dian)(dian)電(dian)(dian)壓(ya)為相電(dian)(dian)壓(ya)的(de)(de)4倍(bei)以(yi)(yi)上，按躲(duo)過內部(bu)過電(dian)(dian)壓(ya)設(she)計(ji)，因(yin)(yin)而(er)(er)僅(jin)對保護雷電(dian)(dian)侵(qin)(qin)害有效(xiao)，對于內部(bu)過電(dian)(dian)壓(ya)不(bu)起任(ren)何保護作用。

然而，運行經(jing)驗證明，當(dang)這類電(dian)(dian)(dian)網發展到一(yi)定規模(mo)時，內部過(guo)電(dian)(dian)(dian)壓(ya)，特別是電(dian)(dian)(dian)網發生(sheng)單(dan)相間歇性接(jie)地(di)時產(chan)生(sheng)的(de)接(jie)地(di)過(guo)電(dian)(dian)(dian)壓(ya)及特殊條件(jian)下產(chan)生(sheng)的(de)鐵磁諧振過(guo)電(dian)(dian)(dian)壓(ya)，已(yi)成為這類電(dian)(dian)(dian)網設備安(an)全運行的(de)一(yi)大威脅，其中以單(dan)相間歇性接(jie)地(di)過(guo)電(dian)(dian)(dian)壓(ya)較(jiao)為嚴重。

近幾年來，經過(guo)冶(ye)金、煤炭、石油、化(hua)工(gong)及(ji)供電(dian)等企業的數百臺運(yun)行(xing)經驗表明，通過(guo)采(cai)用(yong)優(you)能柜將過(guo)電(dian)壓較(jiao)大(da)程度的吸(xi)收(shou)，再配(pei)合選線及(ji)消諧(xie)(xie)模(mo)塊，在消除系統間歇性過(guo)電(dian)壓、鐵(tie)磁諧(xie)(xie)振過(guo)電(dian)壓、判(pan)斷單相(xiang)接(jie)地故障(zhang)線路等各方面(mian)，都收(shou)到了理(li)想的效果，受到用(yong)戶的歡(huan)迎和認可。