outdoor AC HV vacuum on-load disconnectors, with rated voltage 12kV, rated current 630A, rated frequency 50Hz, are capable of making and breaking load current, and also capable of breaking transformer no-load current, a certain length of overhead line, and capacitive current of cable line and capacitors. disconnectors possess functions such as breaking, isolating, making and switchover, and can be coordinated with fuses for protection of distribution lines.