由于民用(yong)(yong)建筑場所內使用(yong)(yong)的(de)(de)多為單相電(dian)(dian)感性負荷，因(yin)其自身功(gong)(gong)率因(yin)數(shu)較(jiao)低，在電(dian)(dian)網中滯后無(wu)功(gong)(gong)功(gong)(gong)率的(de)(de)比重較(jiao)大(da)。為降低電(dian)(dian)網中的(de)(de)無(wu)功(gong)(gong)功(gong)(gong)率，提(ti)高(gao)功(gong)(gong)率因(yin)數(shu)，有功(gong)(gong)功(gong)(gong)率的(de)(de)充分(fen)利用(yong)(yong)，提(ti)高(gao)系(xi)統的(de)(de)供(gong)電(dian)(dian)效率和電(dian)(dian)壓(ya)質(zhi)量，減少線路損耗，降低配電(dian)(dian)線路的(de)(de)成本，節約電(dian)(dian)能，通常在低壓(ya)供(gong)配電(dian)(dian)系(xi)統中裝設電(dian)(dian)容器無(wu)功(gong)(gong)補償(chang)裝置。

在電容器無功補償裝置中(zhong)電(dian)容(rong)柜(ju)起主(zhu)導(dao)作(zuo)用，而其中(zhong)的電(dian)容(rong)器(qi)是主(zhu)要部件，用于(yu)完成無功功率(lv)的補(bu)償。但是電(dian)容(rong)器(qi)屬于(yu)易損易耗品，一般正常壽命(ming)3～5年，如果不及時更換，將會影響補(bu)償功效，并且(qie)存(cun)在嚴重安全隱患(huan)。