Abstract: A method and system for the temperature control of superheated steam in a power plant having a boiler coupled to a turbine, and a turbine bypass valve, wherein temperature control is achieved by regulating opening of the turbine bypass valve. To this end, process quantities indicative of the superheated steam temperature at the boiler outlet, the superheated steam pressure, the turbine inlet temperature, the turbine inner wall metal temperature, and the degree of opening of the turbine bypass valve are fed into a control system in which a mismatch temperature capable of leading steam into the turbine is calculated on the basis of such received process quantities. Then the control system outputs opening or closing operation command signals to the turbine bypass valve. The method is suitable to be carried out by means of a microprocesser.

Abstract: A method of controlling the start of a thermal power plant having a turbine, a boiler for generating superheated steam to drive the turbine, a fuel source for supplying fuel to the boiler, fuel supply controller for controlling the fuel supply from the fuel source to the boiler, and the like. The method includes a step for calculating a desired temperature of combustion gas in the boiler and, in addition, a step of feeding a process factor indicative of the start mode of the turbine. Hence the temperature of combustion gas in the boiler is controlled according not only to the start condition of the boiler but also to the start condition of the turbine, thus reducing the time necessary to start the thermal power plant.