A Comprehensive Induction Machine Model for Multi-Phase Power Flow Studies – Application to Industrial Power Systems and Wind Farms

Abstract

Abstract This paper presents the development of three comprehensive static models of a 3-phase induction machine in phase frame of reference for interfacing with multi-phase power flow programs. The models developed are based on specified slip or specified power, either at the rotor shaft or at the terminals of the induction machine. The development of these models also takes into consideration load torque characteristics. The mathematical formulation of these models is based on branch constraint approach instead of the traditional node constraint approach. This facilitates the arbitrary connections of the induction machine, namely wye, wye-grounded, wye-grounded through impedance, and delta. The models are ideally suited for application in the present trend of operating power and distribution networks with high penetration of renewable energy sources (RES). These models assist in evaluating the performance of wind generators operating under unbalanced system conditions and also in selection of proper phase wise compensation. These static models compute the correct initial operating conditions of induction machines for 3-phase transient stability studies and EMTP-type simulation studies, to evaluate the precise dynamic behaviour of the power system. The procedure for integrating these models in the multi-phase power flow program is also described. The performance of the developed multi-phase power flow program, including static induction machine models, has been evaluated for various power network sizes. The results obtained are verified against the existing literature to clearly demonstrate the efficacy of the proposed methodology.