| 摘要 |
PURPOSE:To control the thermal stress of a rotor with high precision by estimating the steam temperature of a steam turbine from the temperature of the exhaust gas of a gas turbine and controlling the calorific heat of the exhaust gas of the turbine so that the temperature difference from the metal temperature becomes below a prescribed value. CONSTITUTION:The steam temperature is obtained by adding and subtracting the allowable temperature difference from the metal temperature detected by a metal temperature detector 10. The temperature difference of the allowable exhaust gas temperature is obtained from the exhaust gas temperature detected by an exhaust gas temperature detector 9 and the steam temperature, and if said temperature difference is positive, a fuel control valve 12 is opened, and if said temperature difference is negative, the valve 12 is closed so that the temperature difference finally becomes below the allowable temperature difference. When the load is cut off, the fuel control valve 12 and steam reducing valve 8 are speedily closed, and after the number of revolution lowers, the fuel control valve 12 is opened to control the number of revolution of the shaft. Since the metal temperature at this time is high, the exhaust gas temperature is raised by reducing the air quantity of a gas turbine combustor, and the steam temperature is raised close to the metal temperature. Therefore, the thermal stress can be controlled within a limit value.
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