TABLE OF CONTENTS The simulation of electrical machines, whether static or rotative, requires an understanding of the electromagnetic characteristics of their respective windings and cores. Due to their basically symmetrical design, rotating machines are simpler in this respect. On the other hand the latter's transient behaviour involves electromechanical as well as electromagnetic interactions. Electrical machines are discussed in this chapter with emphasis on their magnetic properties. The effects of winding capacitances are generally negligible for studies other than those involving fast fronts (such as lightning and switching).
The first part of the chapter describes the dynamic behaviour and computer simulation of single-phase, multiphase and multilimb transformers, including saturation effects [1]. Early models used with electromagnetic transient programs assumed a uniform flux throughout the core legs and yokes, the individual winding leakages were combined and the magnetising current was placed on one side of the resultant series leakage reactance. An advanced multilimb transformer model is also described, based on unified magnetic equivalent circuit recently implemented in the EMTDC program.
In the second part, the chapter develops a general dynamic model of the rotating machine, with emphasis on the synchronous generator. The model includes an accurate representation of the electrical generator behaviour as well as the mechanical characteristics of the generator and the turbine. In most cases the speed variations and torsional vibrations can be ignored and the mechanical part can be left out of the simulation.
