Research on Design of Guangzhou LCC-HVDC Converter Station Retrofit for VSC-HVDC Converter Station

  Introduction  In order to avoid the commutation failures of receiving end convertor converter station in LCC-HVDC transmission systems， and to improve the voltage stability of receiving end converter station AC system， The research retrofitted Tianguang HVDC receiving end converter station for VSC-HVD， and expansion to 3 GW.

  Method  Based on meeting the various operation modes of flexible DC transmission， facilitating capacity increase， adapting to the level of equipment research and development， and making full use of existing equipment and buildings to reduce the difficulty and cost of transformation. Research compared different converter valve topologies and submodule topologies， studied the setting of the start-up circuit， the electrical wiring of the DC field， and the type of interface transformer.

  Result  Research and analysis show that the capacity-increasing transformation plan recommends the use of a 1.5 GW converter valve per pole， half bridge-full bridge submodule hybrid type， symmetrical bipolar wiring， start-up circuit set on the side of the valve， large transverse size connection transformer.

  Conclusion  This research provides the ideas and methods for the transformation of existing of the existing LCC-HVDC converter station retrofit for VSC-HVDC converter station.