Maximum Loadability Estimation for Identifying Weak Nodes Using Voltage Stability Indices

Voltage stability evaluation has become essential for the reliable operation of power systems, particularly under heavily loaded conditions. With rising power demand and the integration of various power sources, precise system operation is paramount. Determining the maximum loadability limit before a potential voltage collapse is crucial for maintaining stability. Early warning systems can prevent overloads by identifying critical stability thresholds. This study investigates the use of voltage stability indices in power systems to approximate maximum load capacity and pinpoint the most vulnerable nodes. Numerical analyses on IEEE 14 and IEEE 30 bus test systems demonstrate the effectiveness of the Fast Voltage Stability Index (FVSI) and Line Stability Index (L<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">mn</inf>) under normal and high reactive loading conditions. These indices not only identify critical buses but also guide optimal placement of FACTS devices, significantly enhancing the voltage stability margin.