Model Analysis And Application Of Steam Turbine-Generator Considering Saturation

With the fast development of modern science and technology, thecapacity of the steam turbine-generator has improved greatly. The impressionof the steam turbine-generator to the security and stability of the powersystem becomes more and more important. So the research of the on-linecondition monitoring of the large capacity steam turbine-generator becomesmore crucial.The traditional analysis of the operation of the steam turbine-generator isbased on the linear model that doesn't consider the impression of the ironsaturation, so the computation results will be inaccuracy. So the considerationof the iron saturation in the steam turbine-generator model will be beneficialfor the improvement of the on-line condition monitoring and fault diagnosis.For this purpose, the emulation of the saturated parameter of the steamturbine-generator will be done by use of the finite-element method firstly.Then with the results of the emulation, this paper presents a new machinemodel based on the linear synchronous machine model, in which the machineparameters can change according to the vary in the saturation level. Themachine parameter can be estimated by using the least square method in theapplication. Finally, this new machine model is applied in the on-linecondition monitoring of the exciting current and the estimation of thesteady-state stability margin in the steam turbine-generator.According to the experimental data, the results of the exciting currentobtained by this technique show a good agreement with those obtained fromtest. Moreover, the estimation of the steady-state stability margin provides areference for safer and more economic operation of the machine. So, thistechnique can apply in the on-line condition monitoring of the steady-stateexciting currents and the steady-state stability margin in the steamturbine-generator.