Homoclinic Loop and Degenerate Hopf Bifurcations Introduced by Load Dynamics

This letter presents the occurrence and properties of a homoclinic loop bifurcation in a simple power system with induction motor and load tap changer (LTC). This global bifurcation is accompanied by the emergence of an unstable limit cycle, or the disappearance of a stable one. It is also shown that it may coincide with a Hopf bifurcation condition yielding a codimension-2 degenerate Hopf bifurcation.