High voltage soft start cabinet is the starting equipment of high voltage AC motor. It is a three-phase anti parallel thyristor assembly and its electronic control device connected between the power supply and the controlled motor. High voltage solid-state soft start cabinet is composed of multiple thyristors in series and parallel. The output voltage is controlled by controlling the trigger angle of thyristors, which can meet the requirements of different voltages and currents during motor starting. In the process of motor starting, the high-voltage solid-state soft start cabinet increases the terminal voltage of the motor according to the preset starting curve to make the motor accelerate smoothly, so as to reduce the electrical and mechanical impact of motor starting on the power grid, motor and connected equipment. When the motor starts to reach the normal speed, the bypass vacuum contactor is connected and the motor starts. During the operation of the motor, the high-voltage soft start cabinet continues to monitor the motor, measure the motor current and voltage in real time, and provide various fault protection.