Robust method for detection of CUEP for power system transient stability screening

Today´s power systems are operated in significantly stressed state close to their limits. Fast determination of the system response to large disturbances requires online stability assessment. Direct methods appear to be a credible approach in this respect. We propose a robust method for detection of Controlling Unstable Equilibrium Point (CUEP). The CUEP is obtained as a solution of a minimization problem. Our previous approach, the critical trajectory method (CTrj), is applied to the boundary of stability region based controlling unstable equilibrium point (BCU) method. The new method is an extension of the CTrj method with a new criterion described by the potential energy boundary surface property. The improved robustness of the new method is demonstrated through six power system models in comparison with former methods.