Research on operation characteristics and control strategy of hybrid multi-feed HVDC system

Abstract

Flexible DC transmission technology based on voltage source converter (VSC-HVDC) and high voltage DC transmission technology based on grid commutation converter (LCC-HVDC) have complementary characteristics, so the hybrid DC technology combined with LCC-HVDC and VSC-HVDC can make them complement each other and become the development trend of power grid technology in the future. In the existing hybrid multi-infeed DC system, conventional DC transmission (LCC-HVDC) and flexible DC transmission (VSC-HVDC) operate independently and are not coordinated with each other, but there is a blank in the research on the protection coordination relationship between VSC/LCC parallel DC hybrid system and its near area AC system. Therefore, it is necessary to theoretically analyse and study the operation characteristics, control strategy and protection coordination relationship between near-area AC systems of hybrid multi-infeed HVDC systems. Due to the limited space, this paper mainly analyses the operation characteristics and control strategy of hybrid multi-infeed HVDC system, and verifies the correctness of the theory through simulation research. In the next step, the corresponding protection is configured in the above simulation model, and the protection adaptability analysis and protection optimization scheme of hybrid multi-infeed HVDC system are obtained.