Wide-area measurement-based voltage stability indicators by modified coupled single-port models

The coupled single-port model has been proposed recently for wide-area measurement-based voltage stability assessment. This concept relies in decoupling a mesh power grid into the local single-port circuit coupled with an extra impedance. However, underestimations in this approach have been observed in simulation studies. In this paper, a modified coupled single-port model is proposed. Based on real-time PMU measurements of individual load bus, the reactive power response used in the extended Ward-type equivalent will be explored to compensate the reactive power mismatch in the existing model. In addition, a mitigation factor is introduced to modify the Thevenin equivalent parameter of the existing model. Due to the simplicity of the proposed model, several voltage stability indicators can be applied with slight modifications. Simulations on various IEEE test systems are presented to validate the accuracy of the proposed method.