Power flow management and LVRT enhancement by using multi-functional capacitive bridge-type fault current limiter in DFIG system

This paper proposes a new concept of the fault current limiter (FCL) named multi-functional capacitive bridge -type fault current limiter (MCBFCL). It acts as a variable capacitor to manage active power flow under normal operating condition and enhances the low-voltage ride-through (LVRT) performance of wind farms (WFs) under fault operating conditions. The MCBFCL have been presented based on the capacitive bridge-type fault current limiter (BFCL) and is modified to compensate the transmission line impedance in order to manage power flow, while it is not bypassed under normal operating conditions unlike the conventional FCLs. In this paper, first, the power circuit and principle performance of the MCBFCL are discussed. Then time domain simulations are con-ducted in PSCAD/EMTDC environment to check the MCBFCL performance under both normal and fault oper-ating conditions. Also, the MCBFCL performance is compared to the resistive and inductive BFCLs in transmission lines with series capacitive compensation. In this work doubly fed induction generator (DFIG)-based wind tur-bines have been utilized. Simulation results showed that the MCBFCL can manage the power flow under normal operating condition and enhances the LVRT performance of the WF under both symmetrical and asymmetrical fault operating conditions. Also, it has a superior performance in terms of LVRT indices values compared to the resistive and inductive BFCLs.