On the effect of turbine governor gain on bifurcations of subsynchronous resonance in power systems

This paper presents the effect of turbine governor (TG) gain on the bifurcations of subsynchronous resonance (SSR) in power systems. The first system of the IEEE second benchmark model of SSR is considered for the numerical simulations. As the compensation factor increases, the power transfer capability of the transmission line increases. However, the operating point loses stability via supercritical Hopf bifurcation. On further increase of the compensation factor beyond the Hopf bifurcation, the system routes to chaos via torus breakdown. It is found that the value of the TG gain affects the location of the Hopf bifurcation point. High value of TG gain stabilizes the operating point of the system at all realistic compensation factor and therefore eliminates all bifurcations of the system. Time-domain simulation results of the nonlinear dynamical mathematical model carried out at different governor gains and two operating conditions agree with the results of the eigenvalue analysis.