A PMU-based state estimator for networks including classic HVDC links

This paper presents an equality-constrained weighted least squares (WLS) state estimation (SE) model for power systems including classic high voltage direct current (HVDC) links. Synchronized bus voltage and branch current phasor measurements, provided by phasor measurement units (PMUs), are used for the AC network. DC link voltage and current measurements are assumed to be sampled synchronously, time-stamped and reported at the same rate as PMU measurements. Linear AC and DC measurement equations are formulated, by applying the voltage and current phasors in rectangular coordinates. Zero injections and AC/DC coupling equations are treated as linear and nonlinear equality constraints, respectively. To validate the algorithm, a simulation study for a 4- bus hybrid AC/DC test system with one DC link is provided.