S? d?ng cho h? th?ng ?i?n h? th? khi ngu?n c?p ph? t?i b? gián ?o?n B? chuy?n m?ch t? ??ng, giám sát và chuy?n ??i gi?a hai ngu?n ?i?n Chuy?n m?ch three v? trí I - O - II  – It pressured the reliability by adopting a streamlined type which is a simple and thoroughly clean form.– T? ??ng kh?i ??ng ho?c d?ng ho?t ??ng ( c?a DG ) khi ngu?n