Estimating of loadability margin of a power system by comparing Voltage Stability Indices

Estimating the margin in the loadability of the power system is essential in the real time voltage stability assessment. Voltage stability is currently one of the most important research areas in the field of electrical power system. The condition of voltage stability in a power system can be known using voltage stability indices (VSI). The loading margin is one of the most widely known and accepted VSI. Voltage Stability Indices can be useful for estimating the distance from the current operating point to voltage collapse point. The indices can either reveal the critical bus of a power system or the stability of each line connected between two buses in an interconnected network or evaluate the voltage stability margins of a system. The comparison of the performances of these indices is presented and the effectiveness of the analyzed methods is demonstrated through simulation studies in IEEE 14 bus reliability test systems.