The equipment adopts an armored metal closed structure, and the cabinet is separated into four independent function rooms by thin steel plates: the main busbar room supports three-phase rectangular busbar insulation sleeve penetration, the trolley room is equipped with a contact box shield and anti-slip release limit mechanism, the bottom of the cable room is equipped with a removable cover, and the relay room integrates instrumentation and terminal row components. Each chamber is equipped with a directional pressure release channel, and the main loop static contact is automatically opened and closed through the movable curtain plate, and can be extended and connected through the bus bridge to meet the needs of different installation scenarios