Unstable Equilibrium Point for Transient Stability Region Estimate in Power Systems

Abstract—It is well known that the threat of instability governs most aspects of modern power system operation. This being the case, any improvements made in determining the imminence of an unstable condition, or controlling it has great benefits to modern interconnected power networks. In this paper, we first review the well-known closest unstable equilibrium point (closest UEP) method for transient stability region estimate. One key step involved in the closest UEP method is to search for the closest UEP. This paper presents a new search algorithm for the closest UEP so that one can avoid the fractal nature of the Newton–Raphson method which is usually used in the closest UEP method. Finally, we applied the algorithm to three-machine system and obtained satisfactory simulation results. Index Terms—Power systems, transient stability, UEP. I