An Aggregate Induction Motor Model for Industrial Plants

A technique is developed for deriving an equivalent load model to represent the dynamic and steady state effects of a system consisting of induction motors and constant impedance loads interconnected by a network. Motor parameters are calculated from standard specifications, and together with network and load data are incorporated into an admittance matrix which is used to define most of the parameters of the load equivalent. The inertia and running slip are chosen to minimize the error between the transient response of the system and its equivalent. Step responses are calculated using a state approach. Adequacy of the equivalent is validated by comparing the response of the original system and the equivalent to simulated bus voltage change, transformer outage, and remote and local balanced faults using a transient stability program.