A robust and efficient power series method for tracing PV curves

Estimating the voltage collapse point of a power grid is an important problem in power flow analysis. In this paper, we propose a novel power series method (PSM) for tracing the power-voltage (PV) curve and estimating the collapse point. By expanding the power flow equation into power series, a new point on the PV curve can be accurately extrapolated based on a previously solved point. Both forward stepping and backward stepping are proposed so that the proposed PSM can trace both the upper and lower halves of the PV curve. The collapse point is estimated as the intersection of the two half curves. Compared with the conventional continuation method, our PSM is numerically more robust. Compared with the conventional embedding method, our PSM offers superior accuracy and low computational cost.