Analysis of the influence of the turbogenerator equivalent circuit structure on the accuracy of transient processes simulation
Ackground. Currently, for refined modeling of steady-state modes with asymmetry in the stator winding circuit and asynchronous course of turbogenerators complex and detailed equivalent circuits widely used. They are not suitable for the study of instantaneous changes of parameters in time by differential equations. There are methods that allow for the conversion of high-order circuits to simpler, more convenient for the simulation of transient processes. To assess the accuracy of the calculations when using the simplified equivalent circuits of various structures is the relevant problem. Materials and/or methods. To assess the impact of the structure of the equivalent circuit on the accuracy of mathematical modeling and development of recommendations on their application for solution of specific tasks performed a multivariate study of electro-magnetic and electromechanical transient processes under excitation influences leading to a different variation of the rotation speed of the generator rotor. The study analyzed the effect of additional resistance included in the circuit of the stator windings and excitation. Results. The performed research allowed establishing that in the synthesis of circuits convenient for modeling in order to improve the accuracy it is necessary to represent the excitation winding by a multicircuit taking into account its active resistance. Formulated the recommendations on the use of equivalent circuits of various structures for solution of the problems associated with the need to accurately determine the parameters of the dynamic regime in the stator winding and in the excitation winding. Conclusion. For tasks related to the determination of the currents in the stator winding only, it is necessary to build models in such a way that they correspond to the actual frequency characteristics of the conductivities or resistances of the stator winding. For a refined calculation of the current in the excitation winding, it is necessary to use equivalent circuits synthesized on the basis of adequate frequency characteristics of the stator winding and complex coefficients of the stator current distribution in the excitation winding branches.