Influence of Different Practical Models on the First Swing Stability of Turbine Generators

Abstract

There are two popular practical models of synchronous generators used in power system simulation, both based on Park equations, defined as assumed A and assumed B respectively, according to the different assumptions. To study the influence of the different models on the first swing stability calculation precision, the physical essence of the two assumptions are revealed in theory, and it is obtained that assumed A takes account of the mutual leakage flux linkage between field and damping windings and neglects the self-leakage flux linkage of damping winding, the opposite of assumed B. Taking a 300-MW turbine generator as an example, first swing stability limits calculated by two practical models are compared; simulation results are verified by the time-step finite-element model. The influence of line reactance and excitation system on first swing stability limits is studied. Results show that the first swing stability limit calculated by the practical model with assumed A is closer to the result of the time-step finite-element model, since assumed A takes account of the larger mutual leakage flux linkage. Therefore, the practical model with assumed A is more accurate. The result provides reasonable reference to select synchronous generator models in power system simulation.