當市(shi)電(dian)(dian)(dian)供(gong)(gong)電(dian)(dian)(dian)中斷或市(shi)電(dian)(dian)(dian)電(dian)(dian)(dian)壓超限(xian) (±15%或±20%額定輸入電(dian)(dian)(dian)壓)時,互投(tou)裝置將(jiang)立即投(tou)切至逆變(bian)器供(gong)(gong)電(dian)(dian)(dian),在(zai)電(dian)(dian)(dian)池組所提供(gong)(gong)的(de)(de)直流(liu)能(neng)源(yuan)的(de)(de)支(zhi)持下,此時,用戶負載所使用的(de)(de)電(dian)(dian)(dian)源(yuan)是(shi)通過EPS的(de)(de)逆變(bian)器轉換的(de)(de)交流(liu)電(dian)(dian)(dian)源(yuan),而不是(shi)來自市(shi)電(dian)(dian)(dian)