sustainability Article Design of Capacitive Bridge Fault Current Limiter for Low-Voltage Ride-Through Capacity Enrichment of Doubly Fed Induction Generator-Based Wind Farm A. Padmaja 1, Allusivala Shanmukh 1, Siva Subrahmanyam Mendu 2, Ramesh Devarapalli 3 , Javier Serrano González 4 and Fausto Pedro García Márquez 5,* 1 Department of Electrical and Electronics Engineering, JNTUK University College of Engineering, Vizianagaram 535003, India; [email protected] (A.P.); [email protected] (A.S.) 2 Department of Mechanical Engineering, MVGR College of Engineering (Autonomous), Vizianagaram 535005, India; [email protected] 3 Department of Electrical Engineering, Birsa Institute of Technology Sindri, Dhanbad 828123, India; [email protected] 4 Department of Electrical Engineering, University of Seville, 41004 Sevilla, Spain; [email protected] 5 Ingenium Research Group, University of Castilla-La Mancha, 13001 Ciudad Real, Spain * Correspondence: [email protected] Abstract: The increase in penetration of wind farms operating with doubly fed induction generators (DFIG) results in stability issues such as voltage dips and high short circuit currents in the case of faults. To overcome these issues, and to achieve reliable and sustainable power from an uncertain Citation: Padmaja, A.; Shanmukh, wind source, fault current limiters (FCL) are incorporated. This work focuses on limiting the short A.; Mendu, S.S.; Devarapalli, R.; circuit current level and fulfilling the reactive power compensation of a DFIG wind farm using a Serrano González, J.; García Márquez, capacitive bridge fault current limiter (CBFCL). To deliver sustainable wind power to the grid, a F.P. Design of Capacitive Bridge Fault fuzzy-based CBFCL is designed for generating optimal reactive power to suppress the instantaneous Current Limiter for Low-Voltage voltage drop during the fault and in the recovery state. The performance of the proposed fuzzy-based Ride-Through Capacity Enrichment of Doubly Fed Induction CBFCL is presented under a fault condition to account for real-time conditions. The results show that Generator-Based Wind Farm. the proposed fuzzy-based CBFCL offers a more effective solution for overcoming the low voltage Sustainability 2021, 13, 6656. https:// ride through (LVRT) problem than a traditional controller. doi.org/10.3390/su13126656 Keywords: capacitive bridge fault current limiter; fuzzy logic controller; grid connecting point; Academic Editors: Paulo Santos and wind farm Marc A. Rosen Received: 20 May 2021 Accepted: 8 June 2021 1. Introduction Published: 11 June 2021 In 2015, the signatory countries of the Paris agreement agreed to a substantial reduc- tion in global greenhouse gas emissions with the objective of limiting the temperature Publisher’s Note: MDPI stays neutral increase this century to 2 degrees Celsius above pre-industrial levels, while pursuing a with regard to jurisdictional claims in temperature increase limited to 1.5 degrees. In line with these targets, national policies published maps and institutional affil- across the globe have presented their ambition levels based on the deployment of renew- iations. able technologies. The International Renewable Energy Agency states in [1] that to achieve the Paris Agreement targets, all regions should increase their shares of renewable energy use by 2050 by reaching shares of between 70% and 80% of their total final energy mixes by 2050. As far as electricity production is concerned, the share of renewable production in the Copyright: © 2021 by the authors. world should be above 85%. Since these shares of renewable generation will be achieved Licensee MDPI, Basel, Switzerland. mainly through the deployment of variable renewable generation such as wind and solar This article is an open access article PV, according to IRENA, 24% of the investments needed until 2050 to achieve the Paris distributed under the terms and targets will need to be made in renewables, while an additional 23% will be needed for conditions of the Creative Commons electrification and flexibility units that enable the integration of new renewable capacity, Attribution (CC BY) license (https:// totaling $26.4 trillion and $25.3 trillion, respectively [2]. This highlights the importance of creativecommons.org/licenses/by/ emerging technological solutions that enable the integration of new variable renewable 4.0/). Sustainability 2021, 13, 6656. https://doi.org/10.3390/su13126656 https://www.mdpi.com/journal/sustainability Sustainability 2021, 13, 6656 2 of 17 generation sources in pursuit of greater security of supply. In this sense, the present work proposes a control strategy aimed at increasing the reliability and capacity of wind turbines in the presence of voltage dips in the grid, not only to avoid disconnection but also to contribute to the mitigation of failure, which is a step towards guaranteeing the continuity of the electricity supply in a system largely based on renewable sources. The world electricity demand is expanding quickly as a result of cutting-edge in- novation and mechanical development. The significant piece of these power requests is satisfied through non-renewable energy [3]. As a rule, non-renewable energy is subject to the petroleum derivatives coal, oil, and gas, which are exceptionally restricted, just as air is likewise contaminated by utilizing non-renewable sources [4,5]. Along these lines, because of the ecological concerns and insufficiency of petroleum derivative assets, the electric power businesses are putting more accentuation on the environmentally friendly power assets or efficient power fuel sources regarding practical and accessibility possibilities. Because of its low maintenance expense, high creation capacity, no air pollution, and acces- sibility in a few pikes, wind energy is becoming the most visible energy asset and fastest emerging force in comparison to other environmentally friendly power sources. Moreover, wind energy is a perpetual energy asset in the power network [6]. With the presentation of new-age ideas, for example, doubly-fed induction generators (DFIGs) with various elements of synchronous generators, the security of the intensity framework is indemnified against new difficulties [7,8]. At the point when the commitment of DFIGs in the power system is on a small scale, the strength of the power system is influenced modestly. Unexpectedly, with the vast increase in DFIG-based farms in the power system, the dynamic exhibition of the network can be influenced fundamentally by the attributes of the DFIGs. The transient security of power systems coordinated with DFIGs is researched. The expanded joining of DFIG-based wind farms in the power system can have both valuable and hindering consequences for little signal strength and transient strength [9,10]. Wind farm penetration is increasing as there is an increase in demand of power. Such penetration leads to power quality and stability issues when fault occurs. Due to this expansion level, the concerns of grid codes began to shift towards stability issues rather than power quality issues. The existing scientific literature on control strategies to improve the grid integra- tion of wind generators is extensive. A control strategy based on a modular multilevel converter for squirrel cage induction wind generators was presented by Hossain and Abido [11]. Yousefi-Talouki et al. [12] proposed a direct power control technique for matrix converter-fed, grid-connected DFIGs. A new inertia control strategy for a permanent mag- net synchronous generator based on a frequency fuzzy adaptive approach was presented by Li et al. in [13]. Eltamaly et al. [14] presented a control scheme for a doubly-fed induc- tion generator in wind turbines based on a support vector regression algorithm, whose parameters are adjusted by means of a particle swarm optimization method in order to control the wind turbine in the absence of wind speed measurements by the anemometer. Along these same lines, the authors presented a similar approach applied to the control of permanent magnet synchronous generators of wind turbines [15]. Regarding the behavior of the DFIG-based generators in the event of power system faults, the low voltage ride through capability (LVRT) is of great importance. Its require- ment makes the wind farm hold on to the grid [16]. Due to the weight, efficiency, and the active and reactive power controls [17], the DFIG-based wind farms are widely used. In the DFIG stator, windings are exposed to grid connection point (GCP) voltage sag [18]. Due to this sag, there is a chance of overvoltage at DC link and high rotor overcurrents. This dam- ages the rotor side converter (RSC) and makes the wind farm troubleshoot [19]. To meet the LVRT requirement, several methods are employed [20,21]. Liu et al. [22] presented a theo- retical analysis of fault current characteristics of inverter-interfaced renewable generators with fault-ride-through ability. Shafiul Alam et al. [23] proposed a control method based on a non-superconducting bridge-type fault current limiter for DFIG-based wind generators. The authors proposed a control scheme consisting of a constant capacitor voltage main- Sustainability 2021, 13, 6656 3 of 17 tained by the stator voltage source converter controller, while current extraction or injection is achieved by rotor converter controller. Choi et al. [24] analyzed the impact of varying the momentary cessation voltage level on the short-circuit current in inverters of photovoltaic and wind power