Research on Operation Control Strategy of the CSC-HVDC Transmission System Based on Current Reinjection Conversion

The thyristor multi-level current source converter based on the current reinjection conversion technology can realize the controlled shutdown of the thyristor under zero current condition, which provides a new idea for overcoming the shortcomings of the traditional LCC-HVDC system. The use of double-group multilevel converters can realize independent control of the amplitude and phase of the ac output current, thereby providing the possibility to realize the four-quadrant operation of the active and reactive power of the CSC-HVDC system. Based on this, this paper takes the point-to-point HVDC transmission system as the research object, derives the system mathematical model and establishes the control model. A complete digital simulation model of the CSC-HVDC transmission system is built on the PSCAD platform, and the simulation results show that the proposed control strategy can ensure that the system has excellent dynamic and static operating performance under normal and fault conditions of the power grid.