Domains of ferroresonance occurrence by bifurcation diagrams

Ferroresonance can occur in inductive voltage transformers (VT) as a result of disconnecting a busbar or a line section by opening circuit breakers equipped with grading capacitors. This phenomenon is harmful for the electric power system due to the overvoltages and overcurrents it generates, which can damage the VT and the protective and measuring devices connected to it. A possible way to suppress ferroresonance is to connect a damping reactor and damping resistor to the secondary winding of the VT. The sensitivity to circuit parameters and to initial conditions required a systematic approach in order to obtain well defined domains of ferroresonance occurrence. A new approach for finding ferroresonance occurrence domains was developed. The steady state solutions are calculated by the Galerkin method and a bifurcation diagram is drawn using the continuation method. By using the proposed approach continuous and well defined domains can be found