A method for identifying weak nodes in nonconvergent load flows

Though the Newton-Raphson method usually converges to a solution of the simultaneous nonlinear load flow equations, it can occasionally be nonconvergent. A method for identifying weak areas of systems which prevent convergence of the Newton-Raphson method is presented. This information aids load-flow-program users in the modification or correction of system data to obtain convergence. The method is tested on a 28-node test power system and on an 84-node case from a utility company. The method consistently identified the weak node in systems in which a preset weak node had intentionally been placed for testing. The method also identified the same weak area in an industrial case as had engineers familiar with the system