Series VSC-LCC converter with self-commutating and dc fault blocking capabilities

This paper proposes a new topology of converter that possess self-commutating and dc fault blocking capabilities. The converter (SVLC) is composed of series connection of LCC and VSC converters. If connected to wind farms, the VSC converter is used to maintain the ac voltage of wind farm and provide commutation voltage for the LCC while the LCC is used to control the dc voltage of the VSC so as to maintain power balance of the wind farm and the power transmitted by the SVLC. The SVLC combines advantages such as high power, high voltage, low loss, relatively low cost of LCC and the self-commutating ability of VSC. Meanwhile, the SVLC is able to achieve dc fault blocking capability. Simulations in normal operation and during dc faults in PSCAD/EMTDC using detailed switching model verified the feasibility of the proposed topology.