當市電(dian)(dian)供(gong)電(dian)(dian)中斷(duan)或市電(dian)(dian)電(dian)(dian)壓(ya)超限 (±15%或±20%額(e)定輸入電(dian)(dian)壓(ya))時,互(hu)投裝置(zhi)將立即投切至逆變器供(gong)電(dian)(dian),在電(dian)(dian)池組所提供(gong)的(de)直(zhi)流能源的(de)支持(chi)下,此(ci)時,用戶負(fu)載(zai)所使(shi)用的(de)電(dian)(dian)源是(shi)通過EPS的(de)逆變器轉換的(de)交流電(dian)(dian)源,而不(bu)是(shi)來(lai)自市電(dian)(dian)