Modified Secondary-Control-Based Fault Current Limiter for Inverters

Fault current limiters (FCLs) are one of the main solutions to upcoming challenges in the microgrid protection. Regarding the high penetration of distributed generations (DGs) in the future power system, designing cheap and effective FCLs is a necessity. This letter addresses this issue by proposing an embedded FCL operating based on modifying the secondary control of the inverter. As this method is presented for a four-wire system, besides very low implementing cost, it has independency and flexibility to only limit the current of the DG faulted phase. This letter also provides real-time simulation results by real time simulator (OPAL-RT) to compare the proposed method with a virtual-impedance-based FCL to validate its effectiveness. Finally, experimental results are presented to validate the effectiveness of the proposed FCL.