Abstract
Since a synchronous motor is held heavy nonlinearity, the transient stability analysis of it is generally laborious. Conventionally, this analysis has been used numerical solution or equal-area method, whereas this paper is proposed a new transient stability criterion by applying Lyapunov method which is powerful for nonlinear systems to estimate these stability. Lyapunov method is easy to evaluate the system stability without solving the nonlinear differential equations of the motor, and is possible to evaluate the system stability based on a physical concept by a generalized energy function.
The disturbances considered in this paper are abrupt changing of load and dropping source voltage. The influence of machine parameters for the transient stability is studied by analyzing the stability boundaries and the stable limits subjected to these disturbances. The results are obtained that the influence of relative damping coefficient for the transient stability is effectively large and the authors evaluation method of stability using Lyapunov method is more better profitable for stability criterion than the equal-area method. Moreover, good stable limits at changing of load is obtained by this method in comparison with experiments, and validity of authors method results is verified.
