Analysis of forced oscillations in a multimachine power system

Abstract

In this paper, the origin of forced, low frequency oscillations introduced in power systems by low-speed Diesel generators is investigated. Then, the linear models of a multimachine Power System are presented both for an interconnected, and for an autonomous system. Particular emphasis is given to the calculation of the electromechanical oscillation frequencies. A three-machine test system exhibiting a very strong resonance is analysed next. The method of analysis is based upon the computation of the frequency response of a multivariable system. Finally, the electromechanical oscillation analysis and the frequency response computation are applied to the Electric Power System of the island of Crete, where a number of large low-speed Diesel engine driven generators have recently been installed.