Investigations of Voltage/Reactive Power Sensitivity for Voltage Control and Voltage Stability in Unbalanced Distribution Systems

Because of increased DG penetration level, maintaining a good voltage profile in distribution systems is challenging. In addition, because of slow expansion of distribution systems and fast growth of load, voltage stability becomes an important issue. Voltage and reactive power sensitivity, dV/dQ, is one of key important factors in maintaining a good voltage profile and analyzing voltage stability problem. In this work, we investigate some fundamental properties and identify several patterns of dV/dQ based on the IEEE 13-node test feeder. The results have important implications on the application of voltage control and on the validity of modal analysis for voltage stability analysis for three-phase unbalanced distribution systems.