Research on HVDC system parameter domain based on VDCOL dynamic characteristic optimization

During commutation failure(CF), the transient reactive power characteristics of the HVDC system are closely related to the Voltage Dependent Current Order Limiter (VDCOL) control parameters. This paper first establishes a relationship between dc current and reactive power on the rectifier side, revealing the mechanism through which VDCOL control parameters affect the transient voltage and extinction angle at the sending end. Based on this, a parameter domain optimization strategy is proposed to suppress overvoltage and subsequent commutation failure. Then, the range of VDCOL slopes is quantified, delineating the safe operating boundary of the parameters and defining a safe operating parameter domain that considers overvoltage and subsequent commutation failure. Finally, simulations of the HVDC system are conducted on the PSCAD platform. The simulation results show that the strategy in this paper achieves a precise delineation of the VDCOL parameter domain. By optimizing the parameters to change the slope k, the steady-state and transient performance of the system are significantly improved, effectively suppressing the peak transient overvoltage and reducing the likelihood of subsequent commutation failure.