Comparative Stability Analysis of Offshore Wind and Marine-Current Farms Feeding Into a Power Grid Using HVDC Links and HVAC Line

This paper presents the comparative stability analyzed results of integration of a doubly fed induction generator-based offshore wind farm (OWF), a PMSG-based OWF, and a squirrel-cage induction generator-based marine-current farm (MCF) feeding into a power grid through a high-voltage alternating-current line and two high-voltage direct-current (HVDC) links. One of the HVDC links is based on a voltage-source converter (VSC) while the other is a multiterminal configuration that uses three VSCs at the converter station and a VSC at the inverter station. A power oscillation damping (POD) controller for the MT-HVDC system is designed, and the design steps include the selection for the POD controller based on the total effects on the remaining system. A frequency-domain approach based on a linearized system model using calculated eigenvalues and a time-domain scheme based on a nonlinear system model subject to disturbances are systematically performed to compare the damping characteristics contributed by the three transmission schemes. It can be concluded from the simulation results that the proposed MT-HVDC link is capable of rendering better damping characteristics to stabilize the integrated OWFs and MCF feeding into a power grid under a severe fault than the HVAC line and the VSC-HVDC link.