In the wake of increasing the share of renewable energy-based generation systems in the power mix and reducing the risk of global environmental harm caused by fossil-based generation systems, energy storage system application has become a crucial player to offset the intermittence and instability associated with renewable energy systems. Due to the capability to store large amounts of energy in an efficient way, redox flow batteries (RFBs) are becoming the energy storage of choice for large-scale applications. Vanadium-based RFBs (V-RFBs) are one of the upcoming energy storage technologies that are being considered for large-scale implementations because of their several advantages such as zero cross-contamination, scalability, flexibility, long life cycle, and non-toxic operating condition. This review presents the current state of the V-RFB technology for power system applications. The basic working operation of the V-RFB system with the principle of operation of its major components, the design considerations, and the limitations of each component are discussed. It presents technical information to improve the overall performance of the V-RFB by considering the materials of the cell components, modeling methods, stack design, flow rate optimization, and shunt current reduction.INDEX TERMS Energy storage system, flow battery, renewable energy, vanadium redox flow battery.

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In the work reported in this paper, a novel application of the artificial bee colony algorithm is used to implement a virtual inertia control strategy for grid-connected wind energy conversion systems. The proposed control strategy introduces a new heuristic optimization technique that uses the artificial bee colony (ABC) algorithm to calculate the optimal gain value of an additional derivative control loop added to the control scheme of the machine side converter in a wind energy system to enable wind farms to participate in frequency control as specified by recent grid codes. This helps to minimize the frequency deviations, reduce active power deviation in the system, and increase the penetration level of wind energy in power systems. The study was performed in a restructured power system environment. The proposed control scheme and its robustness were evaluated using load–frequency analysis for three real-life transaction scenarios that can occur in an interconnected open-energy market and the validation was carried out using eigenvalue analysis. The results in this study show that the optimal gain of the proposed controller reduces the frequency deviations and improves stability and overall performance of the system.

In an islanded DC microgrid with multiple distributed generators (DGs), the droop control is employed to realize proportional current sharing among the DGs in the microgrid. The action of the droop control causes a deviation in the DC bus voltage which is exacerbated by the line impedance between the DG and the DC bus. In this paper, an advanced distributed secondary control scheme is proposed to simultaneously achieve accurate voltage regulation and cooperative current sharing in the islanded DC microgrid system. The proposed distributed secondary controller is introduced in the cyber layer of the system, and each controller shares information with neighbouring controllers via a communication network. The distributed technique maintains the reliability of the overall system if some part of the communication link fails. The proposed controller uses the type-II fuzzy logic scheme to adaptively select the secondary control parameters for an improved response of the controller. The sufficient conditions to guarantee the stability of the proposed controller are derived using the Lyapunov method. Comprehensive tests under different operating scenarios are conducted to demonstrate the robustness of the proposed control scheme.

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