Doubly fed induction generators (DFIGs) are vulnerable to grid related electrical faults. Standards require DFIGs to be disconnected from the grid unless augmented with a fault ride through (FRT) capability. A fault current limiter (FCL) can enhance the overall stability of wind farms and allow them to maintain grid-code requirements. In this paper, a neuro fuzzy logic controlled parallel resonance type fault current limiter (NFLC-PRFCL) is proposed to enhance the FRT capability of the DFIG based wind farm. Theoretical and graphical analysis of the proposed method are carried out by MATLAB/Simulink software. The performance of the NFLC-PRFCL is compared with other documented FCL devices, e.g., the bridge type fault current limiter (BFCL) and the series dynamic braking resistor (SDBR). The performance of the NFLC-PRFCL is also compared with that of the existing fuzzy logic controlled parallel resonance fault current limiter (FLC-PRFCL). From the simulation results, it is found that the NFLC-PRFCL outperforms its competitors and enables the DFIG to maintain a near-seamless performance during various fault events. INDEX TERMS Doubly fed induction generator (DFIG), fault ride through (FRT), fuzzy logic controller (FLC), neuro fuzzy logic controller (NFLC), parallel resonance fault current limiter (PRFCL).

High penetration of Doubly Fed Induction Generator (DFIG) into existing power grid can attribute complex issues as they are very sensitive to the grid faults. In addition, Fault Ride Through (FRT) is one of the main requirements of the grid code for integrating Wind Farms (WFs) into the power grid. In this work, to enhance the FRT capability of the DFIG based WFs, a Bridge-Type Flux Coupling Non-Superconducting Fault Current Limiter (BFC-NSFCL) is proposed. The effectiveness of the proposed BFC-NSFCL is evaluated through performance comparison with that of the Bridge-Type Fault Current Limiter (BFCL) and Series Dynamic Braking Resistor (SDBR). Moreover, a dynamic nonlinear controller is also proposed for controlling the operation of the BFC-NSFCL. Extensive simulations are carried out in the MATLAB/SIMULINK environment for both symmetrical and unsymmetrical temporary as well as permanent faults. Based on the simulation results and different numerical analysis, it is found that the proposed nonlinear controller based BFC-NSFCL is very effective in enhancing the FRT capability of the WF. Also, the BFC-NSFCL outperforms the conventional BFCL and SDBR by maintaining a near-seamless performance during various grid fault situations.

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This paper proposes a fuzzy logic controlled bridge type fault current limiter (FCL) to enhance the transient stability of multi-machine power systems. The transient stability performance of the fuzzy logic controlled bridge type FCL is compared with that of another static nonlinear controlled bridge type FCL. The total kinetic energy (TKE) of the generators in the system is used to determine the transient stability enhancement index. Also, the critical clearing time has been presented as a stability limit. Instead of conventional reclosing, the optimal reclosing of circuit breakers is considered. Simulations are performed by using the Matlab/Simulink software. Simulation results of both permanent and temporary faults at different points of the IEEE 30-bus power system indicate that the fuzzy logic controlled bridge type FCL can enhance the transient stability of the system well. Also, the performance of the proposed fuzzy logic controller is better than that of the static nonlinear controller.Index Terms-Bridge type FCL, fuzzy logic controller (FLC), nonlinear controller, optimal reclosing, power system transient stability.

Doubly-fed induction generators (DFIGs) have drawn prominent interest in the field of wind power generation, but they are vulnerable to grid faults. Grid codes mandate DFIGs to employ a sort of fault ride-through (FRT) technique during faults. Fault current limiters (FCLs) always help to augment the FRT capability of DFIGs and a non-linear controller boosts their performances. In this study, a non-linear auto-regressive moving average-L2 (NARMA-L2) controller-based bridge-type flux coupling non-superconducting FCL (BFC-NSFCL) is proposed to enhance the FRT capability of the wind farm. The authors analysed the performance of the proposed NARMA-L2-based BFC-NSFCL (NL2-BFC-NSFCL) against that of the conventionally used series dynamic braking resistor (SDBR), bridge-type FCL (BFCL), and proportional-integral (PI) controller-based BFC-NSFCL (PI-BFC-NSFCL). They tested the performance of the NL2-BFC-NSFCL through multiple temporary and permanent fault scenarios and carried out the mathematical and graphical analysis in MATLAB/Simulink platform. They found that the proposed NL2-BFC-NSFCL's performance surpasses the performances of the SDBR, the BFCL, and the PI-BFC-NSFCL. Moreover, the NL2-BFC-NSFCL has faster system recovery capability after the occurrence of any fault than other competitors.