Modular Fault Limiting and Ride-through Coordination for Cost-effective Protection of LVDC Distribution Networks

To enhance the fault handling capacity of low-voltage DC (LVDC) distribution networks and mitigate the detrimental effects of faults on converter apparatus, this research introduces an innovative modular fault suppression and handling strategy. The proposed approach entails the integration of multi-port fault limiting modules (FLM) with DC circuit breakers (DCCBs) and DC transformers, thereby enhancing the system’s current and voltage regulation. This integration allows for the use of economical mechanical DCCBs while improving the fault-ride-through (FRT) capabilities of the conversion equipment. Under normal operating conditions, the FLM are bypassed to reduce system disturbances; in the event of a fault, it is engaged to curtail fault currents and preserve voltage stability. The validity of the proposed method is verified through simulations in PSCAD/EMTDC. Simulation results demonstrate that the proposed strategy effectively reduces the peak fault current and limits the transient voltage compared to conventional schemes. Furthermore, the system successfully achieves a fault ride-through by maintaining the fault current within a safe range of the rated current, ensuring robust protection and rapid recovery.