Contribution of loads to low frequency oscillations in power system operation

Eigen-based tools have normally been used to predict the development of low frequency oscillation in power systems. A method must be developed to study the effect of loading and load characteristics on the development of low frequency oscillations. This paper is concerned about modeling a power system for low frequency oscillations studies. The purpose is to examine the effect of loads and their modeling on the study mentioned. Research shows that low frequency oscillations are a small signal stability problem. This allows the use of Eigenvectors and Eigenvalues to examine the stability of the power system in the advent of load variation. In this study a mathematical model of the dynamic power system must be built and the initial values of the variables in the model calculated using a load flow. The power system model consists of the non-linear equations which must be linearized about the operating values of the system. The system state matrix can then be constructed from the linearized power system model. Software was written in Matlab 7.0 to perform these mentioned computations. This paper also uses tools such as Participation factors and Mode shape. These tools were useful in examining the effect of loads on the system stability.