This paper researches the power control features of HVDC converter under different working conditions of power grid, and HVDC converter based on MLCR-CSC. From the perspective of practical engineering, it designs a coordination operating scheme with two groups of MLCR-CSC (DMLCR-CSC), and makes the double set of multilevel current reinjection converter (DMLCR-CSC) as an HVDC converter. It analyzes the feasibility of DMLCR-CSC power decoupling contrel, and proposes the active power and reactive power decoupling control method. Thyristors of nine-level DMLCR-CSC main circuit enable zero current turn off ZCS characteristics. Under normal working condition, single-phase ground fault on AC-side, two phase short circuit fault on AC-side and short-circuit faults on DC-side can shut down current to zero within 1/6 of a cycle. THD content is not relevant with trigger angle. Simulations verify that HVDC converter based on DMLCR-CSC is a reliable choice for high-voltage and high-power power transmission.