Hopf bifurcation related coherent oscillations between clusters in the bulk power system

We analyze Hopf bifurcation related oscillatory behavior occurring between clusters of an interconnected power system. This phenomenon is discussed through feasibility boundary calculations associated with inter-cluster oscillatory modes of the system´s real-power-angle dynamics. We demonstrate examples of Hopf bifurcation related instabilities occurring between power flow distribution based clusters (weakly coupled power systems) and/or between any coherency based clusters which may also be geographically scattered. This work gives an explanation for the nature of sustained oscillations between coherent groups of generators formed in a large interconnected power system.