Nuclear power plant instrument air system and control method

The invention belongs to the technical field of nuclear power plant air compressors, and discloses a nuclear power plant instrument air system and a control method.The nuclear power plant instrument air system comprises an air compression assembly and an air source supply assembly, and a manual isolation valve, a pneumatic isolation valve, an electric isolation valve, a controller and a pressure gauge are sequentially arranged from an external air source to an isolation valve set; the manual isolation valve can manually disconnect or connect an external air source and the isolation valve set, the pneumatic isolation valve and the electric isolation valve are controlled by a power plant protection and safety monitoring system, the two valves are normally closed, and when the pressure value of the air compression assembly measured by the pressure gauge is reduced to a pressure setting value, the controller opens the pneumatic isolation valve and the electric isolation valve, and the pneumatic isolation valve an