Dynamic equivalent for average system frequency Behavior Following Major Disturbances.

M.L. Chan R.D. Dunlop and F. Shweppe, PAS 91 No.04 July/August 1972 pp 1637-1642

This paper endeavors to model the effects of governor-turbine dynamic on the average system frequency behavior of a multi-generator system after a major generation loss or load change when the system remains in synchronism. The maximum frequency deviation and the time at which the maximum occurs are the main quantities of interest. Two independent concepts are presented to convert a closed-loop, high dimensional, linear ones (the delay and the canonical models). The delay models uses pure time delay to model “fast time constants” and valve motion and converts the closed loop model in to an open loop one. The canonical model expresses the turbine reheats response as a linear combination of a set of bases function and provides a basis for combining may machines into one simplified, low dimensional model. The two models can be implemented concurrently, to give a very large reduction in complexity when a multi-machine system is analyzed.