Multicell Fault Current Limiter

A multicell fault current limiter (MCFCL) is proposed in this paper. The MCFCL is composed of multiple fault current limiting cells. Each fault current limiting cell consists of a fault current limiting inductor and a power electronic module. The proposed MCFCL has the flexibility in expanding the operation voltage by increasing the number of fault current limiting cells. The MCFCL has excellent static and dynamic voltage equalizing capability between different cells, which makes it highly reliable. The MCFCL utilizes the fault energy absorption bypasses instead of varistors to prevent overvoltages across the semiconductor devices, which makes it able to repeat fault current limitation multiple times in a short time interval. Moreover, the MCFCL has rather high efficiency, which is expected to be no less than 99.9% with appropriate semiconductor devices. The operational principles and parameter design methods of the MCFCL are presented. A medium-voltage prototype is developed and tested. The simulation and experimental results are presented to clarify the theory and feasibility of the proposed approaches.