Computerized diagnosis system for fossil and nuclear power plants

In view of the stable supply of electric power, high reliability is required for thermal and nuclear power plants. It is earnestly desired to catch the symptom of abnormality in power plants, to prevent accidents beforehand, and to realize the operation of plants with high rate of operation. As a means for this, it has been attempted to detect plant abnormality early and to clarify the cause by measuring the quantities showing plant conditions, carrying out statistical treatment and frequency analysis, and comparing the measured values and the values calculated with a model contained in a computer. In this paper, the application of computers to the protection of thermal and nuclear power plants from accidents is discussed. The preventive maintenance system for thermal power plants is the general watch system for improving the rate of plant operation, and gives informations for preventing and controlling accidents in normal state and suppressing abnormal symptoms. Boilers, turbines and generators are the objects of this system. A process control computer HIDIC 80 and microcomputers HIDIC 08 are used for the system. The watching of thermal stress and the difference of thermal expansion in steam turbines, automatic boiler control and watch system, and the centralized watch system of nuclear power plants in emergency state are described. Plant diagnosis system was applied in 1976 to No. 1 plant of the Shimane Nuclear Power Station. (Kako, I.)