A Voltage-Clamping Type DC Fault Current Limiter With Low Power Losses

Fault current limiters (FCLs) have high impedance during fault conditions. However, it is inevitable to introduce additional impedance to the system, which may increase power losses, cause overvoltage, and degrade system dynamic performance. A voltage-clamping type dc FCL (VC-FCL) with low power losses is proposed in this article. This topology has nearly no on-state loss. Under the demagnetization effect of the coupled inductor, this topology presents a very small inductance during normal operation, which is beneficial to the dynamic response of the system. Therefore, VC-FCL can be installed directly into the system without replacing the dc reactor. In addition, the number of power electronic devices and costs are reduced by using a metal oxide varistor (MOV) for voltage clamping. The parameter design of the coupled inductor and MOV is produced out to ensure both the current limiting capability and low power losses of VC-FCL. The simulation case study and experiment test are implemented to further verify the good performance of the proposed topology.