September 16, 2010
Analysis of an area within a large interconnected power system under various system configurations and load conditions is often needed in off- and on-line applications. Equivalence isolates the study area and represent the rest of the system by a simplified equivalent model. A new and more comprehensive approach to the equivalence problem is presented which emphasize the design and operational aspect rather than conventional network reduction, and which is based on meeting application specified operational requirements. Result from a test case demonstrate the validity and accuracy of the method as applied to outage analysis load flow studies.
August 13, 2010
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.