Research on Multi-Reactive Power Source Coordinated Control Strategy for Transient Overvoltage Suppression of Renewable Energy Hvdc Sending System

Addressing the issue of overvoltage in renewable energy stations caused by single-pole blocking in new energy DC sending systems, a mathematical model of a HVDC transmission system with a high proportion of renewable energy is established. The impact of HVDC single-pole blocking on the overvoltage level of renewable energy farms and the reactive power support capability of the sound pole are studied. The power adaptation principles and controllable domains of renewable energy grid-connected inverters under different voltage levels are analyzed. Based on the response time of each device, a coordinated control strategy for the sending system is proposed by coordinating the power control of renewable energy converters, the DC control of the sound pole, and the removal of redundant AC filters at the sending end. Finally, a system simulation model is built in PSCAD/EMTDC to verify the correctness of the theoretical analysis and the effectiveness of the control strategy. The simulation results show that the proposed control strategy reduces the risk of overvoltage trip-off in renewable energy units at the sending end under the mono-polar blocking fault.