Study on Fault Control Requirement and Strategy of Large Scale Renewable Energy VSC-HVDC Integration

Although domestic and foreign research institutions have obtained some research results in related fields, they have not conducted in-depth research on the interaction between VSC DC grid and renewable energy, and on the fault rid though and coordinated control technology of VSC DC grid and renewable energy joint system. Most studies have focused on the fault ride though of the system in the case of AC power grid short-circuit faults in renewable energy power plants and peer-to-peer VSC DC grid systems. Basically, the impact of VSC DC grid system faults on the grid connection of renewable energy is not considered. Although the above research results can suppress the rise of DC voltage and provide technical support as a joint fault ride though of renewable energy and DC grid, the system can achieve fault ride though. However, various fault ride though methods will inevitably have a certain impact on the renewable energy generators, and even have an impact on the regulations and standards for renewable energy connected to the DC power system. Therefore, from the perspective of the safety protection of renewable energy, it is necessary to consider the fault ride though method when the AC grid fails in the VSC DC transmission mode. The transmission of Zhangbei renewable energy through the VSC grid is a complex system with multiple wind farms and multi-terminal DC. It is necessary to carry out detailed research in different working conditions and sub-modes. This paper provides the study on fault control requirement and strategy of large scale renewable energy connected to VSC DC grid, and tries to explore potential challenge caused by the integration of renewable energy generation into VSC DC grid.