Power grid practice of suppressing transient overvoltage of sending-end system by ultra high voltage direct current control parameters

The transient overvoltage off-grid problem of new energy in the sending-end network has become an important factor limiting the ultra high voltage direct current (UHVDC) transmission capacity. In this paper, the causes of transient overvoltage during the DC fault process is analysed firstly, then from the perspective of adjusting the reactive power consumption of the converter, taking the Qingyu UHVDC project in China as an actual simulation example, the influence of the DC control mode and current control parameters at the rectifier side on the transient overvoltage is deeply studied. Combined with the transient voltage evaluation results of the actual power grid, guiding suggestions for DC control strategies are given to improve the transmission capacity. The research results have important reference significance for improving the consumption of new energy and the transmission capacity of UHVDC projects.