Modal Analysis of Power Systems

Abstract

In Chapter 2, I discussed the oscillations that may occur in interconnected power systems. By looking at different models, and with different disturbances, I showed examples of the different types of oscillation that can occur. To do this, I performed a considerable number of 10-second nonlinear simulations. It is apparent that in larger systems the use of transient simulation for the analysis of system oscillations could be very time consuming. To study inter-area oscillations, it is often necessary to run simulations for longer than 10 s; 30 s is quite common in practice. Not only is the use of non-linear simulation time consuming, but also it is often difficult to interpret the results. Larger systems may have a number of interarea modes at very similar frequencies, and it can be quite difficult to separate them from a response in which more than one is excited.