The power plant is a special production enterprise with a high degree of automation, and automated production equipment depends on the safe and stable operation of the power supply system. In modern power plants, the DCS control system for large-capacity generators includes various thermal automatic devices, such as automatic adjustment assembly instruments, steam turbine electro-hydraulic digital adjustment devices, boiler interlocking and safety monitoring systems (FSSS), Turbine monitoring instrument (TSI), coordinated control system (CCS), etc., all need a reliable power source. This power source requires that the power supply should not be interrupted regardless of whether the unit itself is interrupted or the power grid fails. This requires large capacity The unit not only has an accident security power supply that can safely shut down the unit, but also requires a UPS power supply that provides high-quality power supply and uninterrupted power supply for the control, monitoring device and the status parameter recording device after the accident.