A Novel Approach to Extended System Frequency Response Model for Complex Power Systems (ESFR)

This paper presents a practical medium-order multi-machine Extended System Frequency Response (ESFR) model that is applicable for the frequency study of large, complex power systems or an island portion due to sudden load disturbances or generator outages. The ESFR model is a simplification of the real system and can be used to capture the essential system dynamics behaviour, commonly associated with high-capacity hydro generation and thermal generating units. Classification of power system generations and developing an equivalent unit for each class is proposed by the first step of this two-step method. The above components are put together in a composite frame, which takes into consideration all significant characteristics and factors related to the frequency response of the system. The IEEE standard model with the best performance for each element has been selected via a comparative analysis in single-machine and multi-machine environments. The second step aims to equalize the effective parameters numerically and comprises two sub-steps. The first sub-step identifies the parameters with considerable impacts on the frequency response of the components via sensitivity analysis. The second sub-step involves extensive comparative studies to find the best formulas for determining the equivalent value of the effective parameters. The graphical interface of an advanced power system software with a user-friendly simulation environment was used for the analysis. The results show that the current approach is capable in terms of accuracy and practicality to capture the diversity of the generating resources in modern power systems.