A novel load-nodal voltage stability index of power system

Voltage stability problems are becoming increasingly evident since large amounts of power are being transferred from long distance and bulk power systems operate close to their stability limits. Accurate recognition of voltage collapse points and rapid analysis of load node voltage stability make it possible for procedures to prevent voltage collapse incidents. These efficacious operations depend on explicit models, rapid indices and very low time cost. In this paper, an efficient method is proposed for finding out voltage collapse point and manifesting voltage stability margins. Although several homologous methods have been used for voltage stability analysis, this developed method is simple, accurate and fast. It is based on a precise model of power network and a terse index of voltage stability margin. The equivalent network model concerns not only the target node but also its connecting buses, which makes it factual and accurate. The index considers both active power and reactive power flows and reflects the voltage stability margins, providing an indication of distance between the operating point and the collapse one. The validity and applicability of the proposed method has been verified through simulation on EPRI-36 bus system.