Series Compensation Operating Limits - A New Concept for Subsynchronous Resonance Stability Analysis

A new concept is presented for analyzing the stability of turbine-generator torsional modes of oscillation in the presence of series compensated transmission lines. A method is described for obtaining a locus representing constant damping of a torsional mode of oscillation as a function of series compensation levels in two transmission lines. A digital computer program named SCOL which performs the computations and plots the results in a directly usable form has been developed and validated against the MANSTAB program, used to establish the IEEE benchmark eigenvalue calculations. The paper includes an example which demonstrates the utility of this analytical tool for studying subsynchronous resonance on a major transmission system in the south-western United States.