Steady‐State Models and Operation of Synchronous Machines

This chapter describes steady‐state modeling and operation of synchronous machines. Synchronous machine concepts based on Faraday's Law with the DC field current on a rotor interacting with the stator sinusoidal alternating current voltages and currents. A synchronous machine consists of a rotor generating a constant‐speed rotating magnetic field inducing alternating currents in the windings on the stator. From electromagnetic induction and circuit laws, the flux linkages and voltages in a synchronous machine can be modeled by four sets of equations. These are: stator flux‐linkage equations; rotor flux‐linkage equations; stator voltage equations; and rotor voltage equations. A per‐unit system is useful to define the base values of various components of a synchronous machine, including the stator, rotor, and amortisseur, so that the machine parameters are relatively invariant with respect to the machine sizes. A synchronous machine is normally designed so that magnetic saturation will occur if it is operated at its rated load condition.