A Control Strategy for Transient Overvoltage Suppression at DC Supply Terminal by a Coordination of Condenser and STATCOM

The transient overvoltage caused by DC commutation failure seriously affects the safe and stable operation of the DC transmission terminal new energy base. The suppression effect of new energy bases is not satisfactory and needs to be improved. In this paper, we analyze the deficiencies and limitations in the reactive power output capability of the condenser and STATCOM in the transient overvoltage process caused by DC commutation failure. To address the issue that the reactive power response speed of STATCOM is lower than the voltage change speed, which will result in overshoot and exacerbation of overvoltage, a control strategy is proposed to suppress STATCOM overshoot through closed lock voltage control. In response to the limitation of slow action time of the excitation regulation control of the condenser and limited reactive power support ability,which solely only relies on the internal potential not changing suddenly in the early stage of faults, a control strategy is proposed. It employs zero excitation for the condenser during overvoltage situation and coordinates control with STATCOM to suppress overvoltage by increasing the voltage change multiple for both the condenser and STATCOM. Finally, the rationality and effectiveness of the proposed control strategy are verified through PSCAD simulation.