Impacts of small and large induction motors on active and reactive power requirment and system loadability

Induction motor loads constitute almost half of the total load in interconnected power system. In power system stability analysis, it is commonly used a single equivalent model to represent whole groups of induction motor load regardless of their horse power rating. This technique may not give an accurate result due to their nonlinear differences. Hence, this paper demonstrates steady-state nonlinear natures of large and small induction motors. Their effects on active and reactive power requirement and maximum loadability of the power network are discussed in detail. The study results show that small and large motors draws different amount of active and reactive powers, leading to differences in system voltage profiles and levels of loadability limit. From this perspective, multiple equivalent models representing individual characteristics of small and large induction motor loads are suggested in order to improve an accuracy of power system steady-state and dynamic simulations.