蒸気タービン熱応力計算および運転指針表示装置の開発

抄録

For rapid and stable power balance control in electric power system, recent thermal power plants are strongly required to perform very rapid startup, shutdown or load change. On the other hand, the operation standards are more strict than ever because of the importance of safe operation of large plants. In the conventional operation standards the sequences for a turbine startup are decided by the state of the turbine waiting for a startup. In order to actualize a safe and rapid operation satisfying both the strict operation standards and the requirement on speed, it is necessary to know the actual values of limitation factors during the operation. One of the most important factors which limit a rapid plant operation is the thermal stress occurring in the turbine rotors. This paper deals with the development of a new equipment which continuously monitors the state of the turbine, computes the thermal stress on real time and indicates the operation guides. The structure of the equipment which consists of mainly analog operational elements and solves the difference-equations expressing the rotor thermal stress is proposed. The necessary number of divisions in the difference-equations is decided from the accuracy point of view. The operational characteristics of large time scale integrators which are the most important computing components in the equipment are analyzed by a digital computer. As the result of the analysis, it is found that the computation error is due mostly to the unideal characteristics of the integrating capacitors. Especially the capacitance deviation and the equivalent capacitance of dielectric absorption have a great influence upon the error. However, it is clarified that by the method proposed in the paper the errors will be eliminated to actualize the useful equipment.These theoretical conclusions are demonstrated by an experimental model.