Phase Modulation Theory of Electromechanical Damping in Synchronous Generators

Although instability from torsional interaction can be predicted through eigenvalue analysis, there has been little understanding of the physical phenomenon. Recently, Kilgore, Ramey and Hall [1] outlined the fundamentals of what is essentially a phase modulation theory. This paper develops their ideas into a rigorous and complete theory whereby quantitative predictions can be made and compared. The torsional instability regions in series capacitor compensated generators can now be explained. Both round rotor and salient pole machines are considered.