An Explicit Direct Method for Transient Stability Analysis of Multimachine Power Systems With Nonzero Transfer Conductances

We propose an explicit analytical direct method for the transient stability analysis of multimachine power systems with nonzero transfer conductances (TCs). The proposed method addresses two issues. In the first issue, we study the transient stabilization of the entire power system through excitation control design. To this end, a globally well-defined Lyapunov function is constructed, and a locally well-defined dynamic passivity-based control law is proposed. The closed-loop equilibrium is therefore guaranteed to be locally asymptotically stable. In the second issue, we study the transient stability property of post-fault initial states. To this end, an optimization-based approach to calculate the critical level set of the proposed Lyapunov function is proposed. This allows to estimate an explicit region of attraction of the closed-loop equilibrium. Therefore, the transient stability property of a post-fault initial state can be directly assessed. A case study on the IEEE 10-machine 39-bus power system, to demonstrate the performance and effectiveness of the proposed direct method, is presented.