State estimation in unbalanced AC/DC networks

Present HVDC links are typically point-to-point or back-to-back, such that their stationary operating state is rather straightforward to derive and incorporate in business-as-usual grid management practices. However, as HVDC connections are expected to transition towards meshed grids, e.g., in the North Sea, AC/DC state estimation is expected to become a crucial addition to the control rooms of the future, to ensure safe and reliable grid operations through real-time monitoring and application of decision support tools. This paper presents a novel, interior-point method-based unified AC/DC state estimator that is fit for future hybrid grids by enabling advanced functionalities such as the ability to capture asymmetric bipole operation.