Determination of transient stability regions in state space using local Lyapunov surfaces

A new approach to the determination of stability regions of multimachine electric power systems is presented, using a Lyapunov function in conjunction with a certain class of unstable equilibrium points. The relevant Lyapunov surface is constructed for each fault, which is considered to be a local approximation to the stability region. Comparison shows that the conservative nature of the second method of Lyapunov is eliminated.