A comprehensive method to compute the controlling unstable equilibrium point

The accuracy of the transient stability assessment provided by transient energy function method depends on the determination of the controlling unstable equilibrium point (CUEP). However, it is still an uncompleted problem to determine the CUEP fastly and accurately. This paper discusses the CUEP calculation methods, such as the BCU method, the dynamic PEBS method and the shadowing method, and then proposes an algorithm for CUEP determination in the light of the reflected gradient system. Furthermore, it proposes a comprehensive method, which could take advantage of the BCU method, the dynamic PEBS method, the shadowing method and the reflected gradient system method, and improve the robustness of the CUEP determination. Simulation results in the IEEE 3-generator 9-bus and New England system show the effectiveness of the proposed method.