Simulation of frequency slow dynamics for interconnected power systems

Abstract

With the development of electric power markets, the requirements of open access and interconnection of power grids, more and more mid and long term instability accidents due to cascading failures are observed in large interconnected power systems. In order to improve frequency slow dynamics stability and security of interconnected power systems and to prevent viability crisis under large and cascaded disturbances, a novel time simulation model for frequency slow dynamics of interconnected power systems is developed in this paper with the assumption of uniform frequency in each area and the particular consideration of the respective dynamics of each area frequency simultaneously and corresponding interaction. In this model, the area center of inertia (COI) dynamics, speed governor and rotor dynamics and frequency-dependant load models are considered. The simulation algorithm is then presented. Numerical testing results for the IEEE 3- area and 30-bus system demonstrate the validity and effectiveness of the model and algorithm presented in this paper.