Integration of Offshore Wind Farm Using a Hybrid HVDC Transmission Composed by PWM Current-Source Converter and Line-Commutated Converter

This article investigates the feasibility of using a hybrid HVDC transmission system for the integration of offshore wind farms (OWF). The proposed hybrid HVDC consists of a pulse width modulation current- source converter (PWM-CSC)and a line-commutated converter (LCC). The PWM-CSC is placed at offshore, while LCC is located at onshore. The PWMCSC may offer similar advantages that a voltage source converter (VSC) for the integration of OWF, e.g the PWM-CSC can supply an island or passive grids without a external commutation voltage and the stations have a relative small footprint, among others benefits. Moreover, both the PWM-CSC and the LCC are current-sourced converter which facilitate the coupling. To date, there are not studies that report the behavior of this type of hybrid topology, so this work can provide a basis for further research. The control design for the entire system is presented and verified in this paper. Simulations are performed using PSCAD/EMTDC under various conditions including AC and DC faults.