Coordination method for DC fault current suppression and clearance in DC grids

The modular multilevel converter (MMC) based DC grid is considered as a future solution for bulk renewable energy integration and transmission. However, the high probability of DC faults and their rapid propagation speed are the main challenges of the development of DC grids. Existing research mainly focuses on the DC fault clearance methods, while the fault current suppression methods are still under researched. Additionally, the coordination method of fault current suppression and clearance needs to be optimized. In this paper, the technical characteristics of the current suppression methods are studied, based on which the coordinated methods of fault current suppression and clearance are proposed. At last, a cost comparison of these methods is presented. The research results show that the proposed strategies can reduce the cost of the protection equipment.