Modelling And Parameter Uncertainty Analysis Of The Steam Turbine And Its Governing System

Steam turbine is one of the most important facilities of thermal power plants and nuclear power plants, its performance and the governing system features have great influence on the security and economy of the unit. Because of the unit's complexity and the demand of optimizing operation and delicacy management, traditional model is hard to achieve the precision requirements of static and dynamic characteristic of system. It's essential to establish a model with high precision and find an efficient way to analyze the key parameters of the steam turbine governing system.Since the traditional model hardly reflects some of the system's dynamic characteristics, an improved mathematical model is proposed in this thesis based on the traditional model, which can reflect more accurately the dynamic characteristics of the steam turbine governing system. Meanwhile, through the analysis of parameters uncertainty on the system's dynamic behaviors and stability, the results which can be used to improve the accuracy of the model and optimize the test process are obtained.The main work and achievements of this thesis are listed as follows:(1) According to the basic principles and practical measured data of relevant devices, an improved steam turbine governing system model is established based on traditional model. The proposed mathematical model can reproduce the system characteristics in detail.(2) Through the comparison with traditional BPA model, the novel steam turbine governing system model has performance of higher accuracy and applicability based on the measured data from a 300 MW thermal unit and a 600 MW thermal unit.(3) In order to analyze the influence of parameters variation on the main calculating results, the results uncertainties due to the variation of time constant of main inlet volumes and steam chest, time constant of the reheater, time constant of crossover piping and low pressure inlet volumes are analyzed through the Monte Carlo Method. It provides a reliable means for developing a reasonable test scheme and building a practical model.The mathematical model established in this thesis effectively increases the simulation accuracy. The model and the uncertainty analysis method can be used as an analysis tool to optimize the operation process and controlling strategy of the thermal or nuclear steam turbine.