當市電(dian)(dian)供(gong)電(dian)(dian)中斷(duan)或(huo)(huo)市電(dian)(dian)電(dian)(dian)壓超限 (±15%或(huo)(huo)±20%額定(ding)輸(shu)入電(dian)(dian)壓)時(shi)(shi),互投裝置將立即投切(qie)至逆變器供(gong)電(dian)(dian),在電(dian)(dian)池組所(suo)提供(gong)的(de)(de)直流能源的(de)(de)支持下,此時(shi)(shi),用(yong)戶負載所(suo)使用(yong)的(de)(de)電(dian)(dian)源是通過EPS的(de)(de)逆變器轉換的(de)(de)交(jiao)流電(dian)(dian)源,而不是來(lai)自市電(dian)(dian)