Voltage stability assessment algorithm to predict power system loadability margin

In this study, a novel voltage stability assessment algorithm (VSAA) is proposed, which can accurately detect the stability stiffness of power systems. To this purpose, VSAA uses only three measured samples of a bus voltage and the power flowing out of the bus to detect the maximum loadability limit of that bus. Although VSAA has a low computational burden and uses only locally measured data, it can consider the impact of small and/or large disturbances that change the Thevenin equivalent network (i.e. PV curve) seen from the target bus and is able to accurately assess the stability status. To examine the performance of VSAA, it was applied and tested on a 4‐bus, IEEE 39‐bus, Nordic32 and IEEE 33‐bus distribution test systems using DIgSILENT PowerFactory software. The static and dynamic simulation results show the advantages of VSAA over other stability indices proposed in the literature and verify its efficiency and accuracy for online applications.