A method to determine closest Hopf bifurcation in power systems considering exciter and load dynamics

Abstract

Saddle-node and Hopf bifurcations have been recognized as the reasons behind power system voltage instability. In general, Hopf bifurcation is found to occur well before the saddle-node bifurcation under system parameter variation. This paper presents a method to determine the closest Hopf bifurcation from the given operating point considering generator, exciter and load dynamics. The closest distance has been computed in load parameter space using an optimization based model. Results obtained on a sample power system network reveals that the stability margin computed with respect to the Hopf bifurcation further shrinks when load dynamics is considered.