Energy function for power systems with transmission losses

Stability analysis of nonlinear systems draws heavily on energy functions. For power systems, energy functions have been developed for single machine systems and for the special case of constant power loads and lossless transmission lines, extended to multimachine systems. In this paper a circuit energy approach is reconciled with the traditional machine equations using the steady state solution for the transmission network. Physically based development of the energy function starts from the model analysed in a stationary reference frame. The monotonic convergence of the energy is demonstrated on a 3 machine system with transmission losses.