電壓互感器簡稱PT和(he)變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)類(lei)似，是(shi)用(yong)(yong)來(lai)變(bian)(bian)(bian)換線(xian)(xian)路(lu)(lu)(lu)上(shang)的(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)儀器(qi)。但是(shi)變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)變(bian)(bian)(bian)換電(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)目的(de)(de)是(shi)為(wei)了輸(shu)送電(dian)(dian)(dian)能，因(yin)此(ci)容量很大，一般都是(shi)以千伏(fu)(fu)安或(huo)兆伏(fu)(fu)安為(wei)計算單位；而電(dian)(dian)(dian)壓(ya)(ya)(ya)互感器(qi)變(bian)(bian)(bian)換電(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)目的(de)(de)，主要用(yong)(yong)來(lai)給測量儀表(biao)和(he)繼電(dian)(dian)(dian)保(bao)護裝置供(gong)電(dian)(dian)(dian)，用(yong)(yong)來(lai)測量線(xian)(xian)路(lu)(lu)(lu)的(de)(de)電(dian)(dian)(dian)壓(ya)(ya)(ya)、功率(lv)和(he)電(dian)(dian)(dian)能，或(huo)者用(yong)(yong)來(lai)在線(xian)(xian)路(lu)(lu)(lu)上(shang)發生故障時保(bao)護線(xian)(xian)路(lu)(lu)(lu)中(zhong)的(de)(de)貴重設備、電(dian)(dian)(dian)機和(he)變(bian)(bian)(bian)壓(ya)(ya)(ya)器(qi)，因(yin)此(ci)電(dian)(dian)(dian)壓(ya)(ya)(ya)互感器(qi)容量很小(xiao)，一般都只有幾伏(fu)(fu)安、幾十(shi)伏(fu)(fu)安，最大也不(bu)超過一千伏(fu)(fu)安。