PMU-based state estimator for power systems including VSC-HVDC links

The aim of this paper is to propose an equality-constrained weighted least squares (WLS) algorithm for state estimation (SE) in electric power transmission systems including voltage source converter (VSC) based high voltage direct current (HVDC) links. The associated measurement model incorporates both AC and DC measurements. For the AC network, phasor measurement units (PMUs) provide voltage and current phasor measurements. DC measurements obtained from the DC lines are assumed to be sampled at the same rate as AC measurements. Then, by applying voltage and current phasors, linear AC and DC measurement equations are formulated in rectangular coordinates. Zero current injections and AC/DC coupling equations are considered as equality constraints. The applicability of the proposed approach is demonstrated by simulations on a 6-bus hybrid AC/DC network.