Steam Turbine Power Plant

Abstract

A steam turbine power plant includes heat-source equipment that heats a low-temperature flow by applying a heat medium and thus generates a high-temperature flow, a steam generator using the high-temperature flow generated by the heat-source equipment, a steam turbine driven by the steam generated by the steam generator, an electric generator that converts rotational motive power of the steam turbine into electric power, a heat-medium controller that controls a supply rate of the heat medium supplied to the heat source equipment, a low-temperature flow controller that controls a supply rate of the low-temperature flow supplied to the heat-source equipment, a prediction device that predicts startup constraints of the steam turbine from control input variables of the controllers when the steam turbine is started, and a control input variables setter so as to prevent data predictions by the prediction device from exceeding limit values of startup constraints.

What is claimed is: 
     
         1 . A steam turbine power plant, comprising:
 heat source equipment that heats a low-temperature flow by applying a heat medium to generate a high-temperature flow;   a steam generator that generates steam using the high-temperature flow generated by the heat source equipment;   a steam turbine driven by the steam generated by the steam generator;   an electric generator that converts rotational motive power of the steam turbine into electric power;   a heat medium controller that controls a supply rate of the heat medium supplied to the heat source equipment;   a low-temperature flow controller that controls a supply rate of the low-temperature flow supplied to the heat source equipment;   a prediction device that predicts startup constraints of the steam turbine from control input variables of the heat medium controller and the low-temperature flow controller when the steam turbine is started;   a control input variables setter that sets the control input variables of the heat medium controller and the low-temperature flow controller from limit values of the startup constraints as well as from a value predicted by the prediction device; and   a control signal output device that outputs command values to the heat medium controller and the low-temperature flow controller in response to the control input variables.   
     
     
         2 . The steam turbine power plant according to  claim 1 , wherein the prediction device computes at least one of a thermal stress and differential thermal expansion of the steam turbine that occur during a previously set prediction time period, as a predicted value of the startup constraints. 
     
     
         3 . The steam turbine power plant according to  claim 2 , wherein the prediction time period is set to be long with respect to a response time of the startup constraints relative to control of the heat source equipment. 
     
     
         4 . The steam turbine power plant according to  claim 1 , further comprising:
 a measuring instrument that measures at least one of a pressure and temperature of the steam supplied to the steam turbine;   wherein correction of a predicted value of the startup constraints is based upon a value measured by the measuring instrument.   
     
     
         5 . The steam turbine power plant according to  claim 1 , wherein:
 the heat source equipment is a gas turbine, the heat medium is a fuel, and the low-temperature flow is a flow of air.   
     
     
         6 . The steam turbine power plant according to  claim 5 , wherein:
 when a load value of the gas turbine equals a previously set point, the control input variables setter holds for a previously set time the command values that are output to the heat medium controller and the low-temperature flow controller.