箱式變電站，又叫預裝式變電所或預裝式變電站。是一種高壓開關設備、配電變壓器和低壓配電裝置，按一定接線方案排成一體的工廠預制戶內、戶外緊湊式配電設備，即將變壓器降壓、低壓配電等功能有機地組合在一起，安裝在一個防潮、防銹、防塵、防鼠、防火、防盜、隔熱、全封閉、可移動的鋼結構箱，特別適用于城網建設與改造，是繼土建變電站之后崛起的一種嶄新的變電站。箱式變電站適用于礦山、工廠企業、油氣田和風力發電站，它替代了原有的土建配電房，配電站，成為新型的成套變配電裝置。
箱(xiang)式變電(dian)站（簡稱箱(xiang)變）是一種(zhong)把高壓(ya)開關設備配(pei)電(dian)變壓(ya)器(qi)，低壓(ya)開關設備，電(dian)能(neng)計量設備和無功補(bu)償裝(zhuang)置(zhi)等按一定的接線方案組合在一個(ge)或幾個(ge)箱(xiang)體內的緊湊型成套配(pei)電(dian)裝(zhuang)置(zhi)。它適(shi)用于額定電(dian)壓(ya)10/0.4KV三(san)相交流系(xi)統中，作(zuo)為線路(lu)和分配(pei)電(dian)能(neng)之用。
與(yu)同容(rong)量的(de)歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)相比較，美式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)的(de)結構更(geng)為合理。由于歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)是將(jiang)(jiang)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)及普(pu)通的(de)高(gao)壓(ya)(ya)(ya)(ya)(ya)(ya)電器(qi)(qi)(qi)設備裝于同一個金屬外(wai)殼箱(xiang)(xiang)體中(zhong)，變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)室(shi)(shi)溫很高(gao)，引起散(san)熱困難，影響出(chu)力；另一方面在箱(xiang)(xiang)體中(zhong)采用普(pu)通的(de)高(gao)壓(ya)(ya)(ya)(ya)(ya)(ya)負荷(he)開關(guan)(guan)(guan)和熔斷(duan)器(qi)(qi)(qi)、低(di)(di)(di)壓(ya)(ya)(ya)(ya)(ya)(ya)開關(guan)(guan)(guan)柜，所以歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)體積較大。美式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)與(yu)歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)結構上(shang)不一樣。從布置上(shang)看，其(qi)低(di)(di)(di)壓(ya)(ya)(ya)(ya)(ya)(ya)室(shi)(shi)、變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)室(shi)(shi)、高(gao)壓(ya)(ya)(ya)(ya)(ya)(ya)室(shi)(shi)不是目字型布置，而是品(pin)字型布置。從結構上(shang)看，這種(zhong)箱(xiang)(xiang)式(shi)變(bian)(bian)(bian)分為前、后兩部分前面為高(gao)、低(di)(di)(di)壓(ya)(ya)(ya)(ya)(ya)(ya)操作間(jian)隔(ge)，操作間(jian)隔(ge)內包括高(gao)低(di)(di)(di)壓(ya)(ya)(ya)(ya)(ya)(ya)接線端子，負荷(he)開關(guan)(guan)(guan)操作柄，無載調壓(ya)(ya)(ya)(ya)(ya)(ya)分節開關(guan)(guan)(guan)，插(cha)入(ru)(ru)式(shi)熔斷(duan)器(qi)(qi)(qi)，油(you)位計等；后部為注油(you)箱(xiang)(xiang)及散(san)熱片，將(jiang)(jiang)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)繞組、鐵芯、高(gao)壓(ya)(ya)(ya)(ya)(ya)(ya)負荷(he)開關(guan)(guan)(guan)和熔斷(duan)器(qi)(qi)(qi)放入(ru)(ru)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)油(you)箱(xiang)(xiang)中(zhong)。
避雷器(qi)(qi)(qi)(qi)也(ye)采用(yong)(yong)油(you)(you)(you)浸式(shi)(shi)金屬(shu)氧化(hua)物避雷器(qi)(qi)(qi)(qi)。變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)(qi)(qi)取(qu)消油(you)(you)(you)枕(zhen)，采取(qu)油(you)(you)(you)加氣隙體(ti)(ti)積(ji)(ji)恒定原則設計密封式(shi)(shi)油(you)(you)(you)箱(xiang)(xiang)(xiang)，油(you)(you)(you)箱(xiang)(xiang)(xiang)及(ji)(ji)散(san)熱(re)(re)器(qi)(qi)(qi)(qi)暴露在空氣中，沒(mei)有散(san)熱(re)(re)困難。低(di)(di)壓(ya)(ya)斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)采用(yong)(yong)塑殼斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)作為(wei)(wei)主斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)及(ji)(ji)出線(xian)斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)。由于(yu)(yu)結構簡化(hua)，這種箱(xiang)(xiang)(xiang)式(shi)(shi)變(bian)(bian)(bian)(bian)電(dian)站的(de)占地(di)面積(ji)(ji)和(he)體(ti)(ti)積(ji)(ji)大(da)大(da)減(jian)小(xiao)，由于(yu)(yu)其(qi)(qi)體(ti)(ti)積(ji)(ji)很小(xiao)再(zai)加上只(zhi)是一側開(kai)門，其(qi)(qi)所需占地(di)面積(ji)(ji)僅是歐式(shi)(shi)箱(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)的(de)1/4，體(ti)(ti)積(ji)(ji)僅為(wei)(wei)同(tong)容量(liang)歐式(shi)(shi)箱(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)的(de)1/5-1/3。美式(shi)(shi)箱(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)高壓(ya)(ya)側采用(yong)(yong)熔斷(duan)器(qi)(qi)(qi)(qi)保(bao)(bao)(bao)(bao)護(hu)(hu)，低(di)(di)壓(ya)(ya)側采用(yong)(yong)塑殼自(zi)動空氣斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)保(bao)(bao)(bao)(bao)護(hu)(hu)，與中國10kV配變(bian)(bian)(bian)(bian)保(bao)(bao)(bao)(bao)護(hu)(hu)方(fang)(fang)式(shi)(shi)相同(tong)。高壓(ya)(ya)熔斷(duan)器(qi)(qi)(qi)(qi)保(bao)(bao)(bao)(bao)護(hu)(hu)變(bian)(bian)(bian)(bian)壓(ya)(ya)器(qi)(qi)(qi)(qi)內(nei)部故障，自(zi)動空氣斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)保(bao)(bao)(bao)(bao)護(hu)(hu)低(di)(di)壓(ya)(ya)側線(xian)路(lu)(lu)(lu)(lu)的(de)過電(dian)流、短路(lu)(lu)(lu)(lu)、欠電(dian)壓(ya)(ya)故障。美式(shi)(shi)箱(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)存在的(de)缺(que)點。由于(yu)(yu)負荷開(kai)關浸在油(you)(you)(you)里，油(you)(you)(you)被(bei)電(dian)弧(hu)碳化(hua)、分解(jie)，產生乙炔等有害氣體(ti)(ti)，使(shi)得性能下降，曾發生事故。看不(bu)到明(ming)顯斷(duan)開(kai)點，檢修不(bu)方(fang)(fang)便。因為(wei)(wei)美國低(di)(di)壓(ya)(ya)保(bao)(bao)(bao)(bao)護(hu)(hu)及(ji)(ji)計量(liang)方(fang)(fang)式(shi)(shi)與中國不(bu)同(tong)，美式(shi)(shi)箱(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)本(ben)身(shen)不(bu)帶低(di)(di)壓(ya)(ya)保(bao)(bao)(bao)(bao)護(hu)(hu)和(he)計量(liang)。為(wei)(wei)滿(man)足國內(nei)用(yong)(yong)戶的(de)需要(yao)，國產箱(xiang)(xiang)(xiang)變(bian)(bian)(bian)(bian)在低(di)(di)壓(ya)(ya)側加裝低(di)(di)壓(ya)(ya)配電(dian)柜。由于(yu)(yu)箱(xiang)(xiang)(xiang)式(shi)(shi)變(bian)(bian)(bian)(bian)長期處于(yu)(yu)太陽的(de)直(zhi)曬下，影響(xiang)塑殼斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)的(de)散(san)熱(re)(re)，使(shi)得斷(duan)路(lu)(lu)(lu)(lu)器(qi)(qi)(qi)(qi)不(bu)能正(zheng)常(chang)開(kai)斷(duan)負載(zai)及(ji)(ji)短路(lu)(lu)(lu)(lu)電(dian)流，易引發高壓(ya)(ya)側故障。
