Three-Port Small Signal Admittance-Based Model of VSCs for Studies of Multi-Terminal HVDC Hybrid AC/DC Transmission Grids

Multi-terminal high voltage direct current (HVDC) systems, together with AC transmission systems and source converters (VSCs), form hybrid AC/DC grids complex dynamic transient interactions. VSCs characterization taking into account DC- AC-side dynamics in order to study these interactions is not yet well solved. This paper presents a three-port transfer admittance-based matrix model of that can be applied for such purpose. It derived from dq-complex space vectors characterizes both AC- DC-side by relating voltages three-dimensional admittance which considers the VSC outer control loops. The also proposes systematical procedure studying multi-terminal HVDC Norton method, where proposed easily included matrix. allows grid using impedance-based stability criteria. are grid. PSCAD/EMTDC simulations used validate application.