Some new solutions to ferroresonance problem in power system

A parametric equation of the envelope on the G¿1(jw) plane for the general polynomial-type nonlinearity is derived. An analytical method has been suggested for the evaluation of threshold frequency for the occurrence of ferroresonance. Mathematical equations have been deduced for computing the jump-to points for quintic nonlinearity. A generalised equation for asymptotic values of percentage unstable zone for various types of nonlinearities has been derived. New definitions for jump-up severity and jump-down severity are introduced. A system due to Swift has been analaysed for the purposes of illustration.