A LARGE-SCALE HIERARCHICAL DIGITAL CONTROL SYSTEM APPLICATION TO A GAS/ STEAM COMBINED CYCLE POWER PLANT

In practical applications to large-scale power plant control systems, more and more digital controllers, computers and communication links are being used in recent years. A control system of a gas/steam combined cycle power plant is described as a typical example of such control systems and it is discussed how they are used and how hard-wired control systems are still used as current practice. The outstanding features of this combined cycle control system is as follows. First, it is also of such an enormous scale as using more than 100 digital controllers and computers and has a three level hierarchical configuration to have a non-stop characteristic as a whole plant. Second, it has three functions; optimal operation control to attain the highest efficiency of the plant, comprehensive automation to reduce the operator's burden and excellent manmachine communication to provide him with the easiest operation. The combination test with a plant simulator is very effective in this kind of complex system to find system problems before shipment. Computers are also used for this plant simulator which simulates plant dynamics.