Evaluation of an algorithm for the effective damping of parallel turbo-generators

An approximate algorithm for describing the effective damping of unequally loaded identical turbogenerators was proposed by B.L. Agrawal and R.G.Farmer (1988). The results of an investigation to determine the usefulness of this effective damping algorithm are given in the present work. The system under study consists of two generators synchronized in parallel through a series-compensated transmission line to an infinite bus. The actual system parameters used in the paper are those of a laboratory microalternator system at the University of Natal whose characteristics were designed to closely match those of an actual system. It is found that, when the torsional damping levels are low, the ability of the algorithm to accurately predict the effective damping of parallel turbogenerators for a particular mode is reduced as the difference between the load-dependent torsional damping of the individual units increases