Improving Fault Ride-Through Capability of Inverter-Based Distributed Generations Using Fault Current Limiter

By increasing the penetration level of the inverter-based distributed generations (IBDGs) in power system, their fault ride through capability has become one of the essential issues of the new grid codes. This paper proposes a novel method to limit inverter fault currents which are used in DGs. To achieve FRT, interface-inverter operates as a controlled voltage source during normal operation as well as fault condition. The proposed FRT technic employs dc link bridge type non-superconductor fault current limiter (NSFCL) module with capability of controlling the magnitude of the fault current to limit inverter output current during fault condition. At steady state, dc link NSFCL module has not important role on overall IBDG performance. But, at the event of the network fault, by means of this module, it is possible to restrain inverter output currents to a desired value. Also, IBDG is capable to stay connected with the utility at zero grid voltage. The analytical analysis is provided in each switching interval to highlight the impact of the dc link NSFCL on inverter fault current limitation. The effectiveness of proposed scheme is validated through the simulation studies in PSCAD/EMTDC environment.