Reliable steady state voltage stability limit estimation using Newton-Raphson-based method

The paper presents the use of Newton-Raphson (N-R) method combined with the discrete Fourier transform and robust Padé approximation (NR-DFT-Padé) to obtain the saddle-node bifurcation points (voltage stability limit) and the high voltage solution branch for load buses of a power system. This is of potential great advantage to existing N-R based software users because the problem of Jacobian matrix singularity at the voltage collapse point is avoided. A comparison with both, the holomorphic embedding load flow method (HELM) and exact bus values, is presented. It shows that the NR-DFT-Padé method extrapolation has a close approach to the saddle-node bifurcation points (SNBP).