Overview of HVDC Auxiliary Control Technology to Improve the Transient Stability in Receiving Side Power Grid of UHVDC

Abstract:
Long distance and large capacity power transmission is an important characteristic of China's power grid, and HVDC has become an important form of transmission. With the continuous construction of UHVDC transmission projects and the increasing proportion of renewable energy and other types of generating resources, UHV AC / DC receiving side power grid presents the characteristics of more complex power coupling, multiple voltage regulation means and different voltage response characteristics of controlled objects. The voltage security, reliability and economic operation of UHV AC / DC receiving side power grid are facing new challenges. DC system has the advantages of fast controllable power, large adjustable capacity and short-term overload ability. Through appropriate auxiliary control, the transient stability performance of AC / DC system can be effectively improved. Though DC auxiliary control was widely applied, it can be improved by considering the structural characteristics and stability characteristics of AC power grid, the coordination with AGC in AC system, the optimal coordination of multi time scale dynamic reactive power, the coordination with flexible DC system, and the design considering the characteristics of generation-grid-load-storage, so as to play a greater role.