Phasor-measurement-based voltage stability margin calculation for a power transfer interface with multiple injections and transfer paths

For complex power transfer interfaces or load areas with multiple in-feeds, we present a method for phasor-measurement-based calculation of voltage stability margins. In the case of complex transfer paths with multiple injections, a radial system approach may not be sufficient for voltage stability analysis. Our approach provides voltage stability margins considering the full fidelity of the transfer paths. In this paper, we extend a previously proposed phasor-measurement-based approach and apply it to a voltage stability-limited power transfer interface using synchronized phasor measurements from loss-of-generation disturbance events. Previous work employed a simple radial system or modeled a power transfer interface using only one generator. In our approach, we use the PMU data to model multiple external injections that share the power transfer increase, and we employ a modified AQ-bus power flow method to compute the steady-state voltage stability margins. We demonstrate the method using real PMU data from disturbance events in the US Eastern Interconnection.