當(dang)市電(dian)(dian)供電(dian)(dian)中(zhong)斷(duan)或市電(dian)(dian)電(dian)(dian)壓超限 (±15%或±20%額定輸入電(dian)(dian)壓)時(shi),互投裝置將立即投切至逆變(bian)器供電(dian)(dian),在電(dian)(dian)池組所提供的(de)直(zhi)流(liu)能(neng)源(yuan)的(de)支(zhi)持下(xia),此(ci)時(shi),用戶負載所使用的(de)電(dian)(dian)源(yuan)是通過EPS的(de)逆變(bian)器轉換的(de)交流(liu)電(dian)(dian)源(yuan),而不是來自市電(dian)(dian)