當市電(dian)(dian)(dian)供電(dian)(dian)(dian)中斷或(huo)(huo)市電(dian)(dian)(dian)電(dian)(dian)(dian)壓(ya)超限 (±15%或(huo)(huo)±20%額定輸入(ru)電(dian)(dian)(dian)壓(ya))時,互(hu)投裝置(zhi)將立即投切至逆(ni)變器供電(dian)(dian)(dian),在電(dian)(dian)(dian)池組所提供的直流能(neng)源的支持下,此(ci)時,用戶(hu)負載所使用的電(dian)(dian)(dian)源是(shi)通過EPS的逆(ni)變器轉換的交流電(dian)(dian)(dian)源,而不是(shi)來自市電(dian)(dian)(dian)