Voltage Stability Index Based on Multi-bus Reactive Power Loading

Abstract

Voltage stability analysis provides an assessment of the weak, unstable or uncontrollable sections of the power system network that may pose a risk for future load growth due to unexpected voltage collapse. Different methods of determining susceptible buses have been demonstrated over the decades, with V-Q curves being used to determine the critical point and stable operating region of a particular load bus. However, the underlying mutual influences which result from how buses are interconnected, haven't been correlated directly to the voltage profile and stability of load buses. This paper aims to exploit the combined effect that interconnected load buses have on each other, under uniformly distributed multi-bus loading conditions and the conventional method of the sole bus loading analysis, to predict better the strength of a load bus by using a V-Q curve based index. This variable-state-based approach was compared with the inherent network structural-based method giving a broader scope of the system characteristics under various loading states.