Research On Thermal Economic Diagnosing Methods For Operation Of Steam Turbine

The thermal economic analysis of steam turbines is one important parts of the thermal economic analysis of power plants. Through analyzing and diagnosing the economy of steam turbines, the operation and reform in saving energy for steam turbines can be guided, and the economy of steam turbines can be effectively enhanced. Therefore studying the diagnosis methods of operation economy is of meaning and importance.Firstly, the disadvantageous of ideal cycle thermal efficiency as the index of regeneration system is analyzed in this paper, and the improvement in defining method of ideal cycle thermal efficiency is given. Also, the viewpoint is pointed out that the improved ideal cycle thermal efficiency can effectively evaluate thermal economy of thermodynamic system. As the same time, aiming at the shortcoming of equivalent enthalpy drop method, the improved equivalent enthalpy drop method is given, and the reasonableness of the improved equivalent enthalpy drop method is proved. Secondly, the calculating method of the power relative internal efficiency and the enthalpy relative internal efficiency are introduced, and the advantage and disadvantage of the two kinds of relative internal efficiency used as indexes of thermal economy are comprehensively compared. Then the viewpoint is proposed that using power relative internal efficiency is in favor of evaluating thermal economy of steam passage in steam turbine. The calculating results of two efficiencies in diagnosing the economy are close. And the mathematics model is introduced to prove that the power relative internal efficiency is valid to diagnose the economy of steam passage in steam turbine. Finally, combined with the improved equivalent enthalpy drop method and power relative internal efficiency, the new thermal economic diagnosis method for steam turbine operation is proposed. The validity of the new diagnosing method is proved using actual data of a 300MW steam turbine.