甘肅箱式變電站（簡(jian)稱箱變）是一(yi)種(zhong)把(ba)高壓(ya)開(kai)關(guan)設備配(pei)電(dian)變壓(ya)器，低壓(ya)開(kai)關(guan)設備，電(dian)能計量設備和(he)無功補償裝(zhuang)置等按一(yi)定(ding)的接(jie)線方(fang)案組合在一(yi)個(ge)或幾個(ge)箱體(ti)內的緊湊(cou)型成套(tao)配(pei)電(dian)裝(zhuang)置。它適(shi)用(yong)于額定(ding)電(dian)壓(ya)10/0.4KV三相交流系統中，作為線路和(he)分配(pei)電(dian)能之用(yong)。

與同容量的歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)相比較，美式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)的結(jie)(jie)構更為(wei)(wei)合理(li)。由于(yu)歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)是(shi)將變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)及普通(tong)的高(gao)(gao)(gao)壓(ya)(ya)(ya)(ya)(ya)電器(qi)(qi)(qi)設備裝于(yu)同一(yi)個金屬外殼箱(xiang)(xiang)體(ti)中(zhong)，變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)室(shi)溫(wen)很高(gao)(gao)(gao)，引(yin)起散熱困難，影響出力；另一(yi)方面在箱(xiang)(xiang)體(ti)中(zhong)采(cai)用普通(tong)的高(gao)(gao)(gao)壓(ya)(ya)(ya)(ya)(ya)負荷開(kai)關(guan)(guan)和熔(rong)斷(duan)器(qi)(qi)(qi)、低(di)壓(ya)(ya)(ya)(ya)(ya)開(kai)關(guan)(guan)柜，所(suo)以歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)體(ti)積較大。美式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)與歐(ou)式(shi)箱(xiang)(xiang)變(bian)(bian)(bian)結(jie)(jie)構上不(bu)一(yi)樣(yang)。從布(bu)置上看(kan)，其低(di)壓(ya)(ya)(ya)(ya)(ya)室(shi)、變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)室(shi)、高(gao)(gao)(gao)壓(ya)(ya)(ya)(ya)(ya)室(shi)不(bu)是(shi)目(mu)字型(xing)(xing)布(bu)置，而(er)是(shi)品字型(xing)(xing)布(bu)置。從結(jie)(jie)構上看(kan)，這種箱(xiang)(xiang)式(shi)變(bian)(bian)(bian)分為(wei)(wei)前(qian)、后(hou)兩部(bu)分前(qian)面為(wei)(wei)高(gao)(gao)(gao)、低(di)壓(ya)(ya)(ya)(ya)(ya)操(cao)作(zuo)間(jian)隔(ge)，操(cao)作(zuo)間(jian)隔(ge)內包括高(gao)(gao)(gao)低(di)壓(ya)(ya)(ya)(ya)(ya)接線端(duan)子，負荷開(kai)關(guan)(guan)操(cao)作(zuo)柄(bing)，無載調壓(ya)(ya)(ya)(ya)(ya)分節(jie)開(kai)關(guan)(guan)，插入式(shi)熔(rong)斷(duan)器(qi)(qi)(qi)，油(you)(you)位計等；后(hou)部(bu)為(wei)(wei)注(zhu)油(you)(you)箱(xiang)(xiang)及散熱片，將變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)繞組(zu)、鐵芯、高(gao)(gao)(gao)壓(ya)(ya)(ya)(ya)(ya)負荷開(kai)關(guan)(guan)和熔(rong)斷(duan)器(qi)(qi)(qi)放入變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)油(you)(you)箱(xiang)(xiang)中(zhong)。

避雷器也采用油浸式金屬氧化物避雷器。變壓器取消油枕，采取油加氣隙體積恒定原則設計密封式油箱，油箱及散熱器暴露在空氣中，沒有散熱困難。低壓斷路器采用塑殼斷路器作為主斷路器及出線斷路器。由于結構簡化，這種箱式變電站的占地面積和體積大大減小，由于其體積很小再加上只是一側開門，其所需占地面積僅是歐式箱變的1/4，體積僅為同容量歐式箱變的1/5-1/3。美式箱變高壓側采用熔斷器保護，低壓側采用塑殼自動空氣斷路器保護，與中國10kV配變保護方式相同。高壓熔斷器保護變壓器內部故障，自動空氣斷路器保護低壓側線路的過電流、短路、欠電壓故障。美式箱變存在的缺點。由于負荷開關浸在油里，油被電弧碳化、分解，產生乙炔等有害氣體，使得性能下降，曾發生事故。看不到明顯斷開點，檢修不方便。因為美國低壓保護及計量方式與中國不同，美式箱變本身不帶低壓保護和計量。為滿足國內用戶的需要，國產箱變在低壓側加裝低壓配電柜。由于箱式變長期處于太陽的直曬下，影響塑殼斷路器的散熱，使得斷路器不能正常開斷負載及短路電流，易引發高壓側故障。