Abstract: In view of the failure of a high-voltage motor control cabinet in a cement factory, the cause of the failure was analyzed and calculated from two aspects: short-circuit current and overvoltage of the system through the damage of faulty components and the on-site operation process. Then take the corresponding countermeasures to restore the operation of the equipment, formulate the operation procedures of the high voltage motor control cabinet to avoid similar failures and accidents, and improve the reliability of the equipment operation.