Flexible approach to dynamic simulation of voltage collapse phenomenon

This paper presents the dynamic simulation of voltage collapse phenomenon in a flexible manner concerning modelling complexity. In that respect a special attention has been paid to modelling aspects of induction motor as a representative of variety of loads. A complete mathematical model used in this paper for the study of dynamic behaviour of an induction motor consists of five differential equations. This set of equations is solved by using the Runge-Kutta method. As a parallel model a simplified approach is considered (without differential equations) reduced to algebraic network equations and the equation of motion. The effect of transformers equipped with automatic under load tap changers is also simulated. The complete model is rigorous enough in order to calculate the precise voltage-time and P-U curves during the induction motor start-up procedure, while the simplified model can be used for calculation of P-U curves only. Results from this study can be used for real-time system control actions and for induction motor relay settings.