Controllable DC Saturated Core Fault Current Limiter with Loss Reduction

Because of the increased fault current rate and lack of zero current in DC networks like rail transport lines, using fault current limiters (FCL) necessitated a different topology for network elements. FCLs based on core saturation have less of an impact on the network and are less flexible when it comes to handling different kinds of faults because they can not be controlled in terms of time when lowering the fault current. Some FCLs are not time-controllable and have losses in the network before the fault. These factors contribute to their shortcomings. This paper investigates on fast-response FCLs using permanent magnets(PM) and core saturation. These FCLs can control the time of fault current reduction during DC circuit breaker (DCCB) operation, also it is possible to reduce the amount of fault current, which is one of the critical fault parameters, by adding control modes that include two control coils and their drive circuit. The time setting is done to observe the most significant effect at the moment of the fault (DCCB operation). At last, by adjusting the voltage and control coils turn number, in addition to reduce the number of turns of the main coil connected to the network, which causes a reduction in the impedance of the path (reduction of losses) before the fault, have time control on the fault current rate. The fault current limiter designed in the desired DC network is validated by using the finite element simulation method in Ansys Maxwell software.