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The incorporation of clean sources into the power grid, along with the introduction of power electronic gadgets to regulate loads that are nonlinear, had a significant effect on power quality (PQ). Nevertheless, PQ emerges as the primary issue for the integration of these intermittent renewable sources. This study combines the advantageous characteristics of the Sliding mode controller (SM-C) and fractional-order proportional integral derivative controller (FPIDC) to manage both the shunt and series active filters of the Unified Power Quality Conditioner (UPQC) integrated with the wind power system (WPS) and battery systems (BS). The primary objective of the proposed system is to maintain a consistent voltage across the DC Link capacitor, even when there are fluctuations in load and wind velocity. Additionally, the system aims to reduce the presence of harmonics in waveform of current signal, improve power factor (PF), and mitigate any disruptions or imbalances in the source voltage. The effectiveness of the created model has been assessed by four case studies involving diverse load types and grid voltage situations, including fluctuations. Besides, to validate the developed method the comparative analysis is conducted with respect to other methods like PI and fuzzy logic controllers, as well as with other ways documented in the literature. [ABSTRACT FROM AUTHOR]

In a DC microgrid, the main aim of power management is to maintain the balance of active power between renewable sources, storage batteries, loads, and distribution grid which can be represented by stable DC-link voltage. This paper proposes an adaptive strategy for power flow management of a stand-alone hybrid renewable energy system (HRES) consisting of a wind turbine generator, photovoltaic cell, battery energy storage (BES), and load by optimizing the gain of the PI controller in the battery storage system using the particle swarm optimization-based firefly algorithm (PSO-FA). A part of the PSO algorithm is utilized for improving velocity and attractiveness of the firefly algorithm thereby increasing the rate of convergence in the PI controller. This control technique improves gain constant by generating control pulses for charging and discharging of the BES system in order to make optimum use of renewable energy sources and to stabilize the voltage of the DC-link. From the simulations done in MATLAB/SIMULINK, it is observed that conventional trial- and error-based PI tuning produces high overshoot, whereas the proposed method produces better performance with less overshoot. Maintaining constant DC-link voltage, the instantaneous power generation under various conditions of generation and load consumption is managed by monitoring the state of charge of battery. This approach can be used as a complement for improving the performance of PI controllers designed by conventional methods. [ABSTRACT FROM AUTHOR]

This paper improves a previously optimization approach to accomplish an enhanced total cost of electricity (TCE). Based on the integration of many energy deposits for supporting the primary Renewable Green Energy Source (RGES), the whole system is modeled with improved manner, which contributes to well achieve a more comprehensive write-up of the studied formulation problem. To decrease the TCE of the system containing a photovoltaic/wind turbine with battery storage system, the so-called virus colony search (VCS) algorithm is developed. Hence, the association of a lead-acid battery devoted to absorption of the high fluctuations is essential, which can contribute to the operational safety of the system. Thus, techno-economic analysis and cost-effectiveness evaluation are investigated. By depicting TCE as a key factor in this study and compared with other conventional algorithm, a reliability analysis is elaborated in accordance with the lowest cost of electricity. The obtained results prove a high level of economic feasibility in agreement with some evaluation criteria by achieving the lowest TCE. The benefit of the optimization based on VCS algorithm is successfully demonstrated in accordance with highest reliability by a significant saved cost. The results of the optimization display that savings in TCE is 14,792 $ as compared to the calculation process without using VCS algorithm. [ABSTRACT FROM AUTHOR]

The availability of solar resources has led to the utilization of photovoltaic (PV) system for the generation of a clean electricity and reduction of greenhouse gas (GHG) emissions. The techno-economic assessment of a medium scale microgrid system is investigated in this work by utilizing some key performance indicators (KPIs). These KPIs are used as the benchmarks to study the economic impacts of PV in the grid-connected power system for 10 selected locations across the nine provinces of South Africa. The HOMER package is utilized in the study to obtain viable solutions that will mitigate the undesirable technical and economic issues that come up during the grid integration. The research work is carried out by utilizing the surface meteorology and solar energy data provided by the National Aeronautics and Space Administration (NASA) for assessment of the proposed microgrid system. The outcomes of the study show that the annual average daily radiation varies from 4.3 kWh/m2/day in Durban to 5.749617 kWh/m2/day in De Aar. It is deduced from the work that De Aar is the most feasible location among the 10 selected sites for the installation of PV in terms of cost of energy (COE), net present cost (NPC), net energy purchased, energy purchased, energy sold, energy charge, annual utility bill savings and revenue with the following values: 0.181 R/kWh, R 219244.90, 3676 kWh, 32979 kWh, 29303 kWh, R7942.9891, R62473.0109, and R22759.6401. The outcomes of the research work indicate that exploitation of solar resources is an efficient means of accomplishing sustainable energy development. [ABSTRACT FROM AUTHOR]

Distributed generation with battery energy storage (BES) system is an alternative solution for stand-alone AC supply systems. This article addresses the issue of voltage variability of stand-alone microgrid with the adoption of intelligent micro-source controllers. The high energy density of the BES system is used to compensate the voltage fluctuation. A control mechanism is designed to regulate the flow of electrical energy from BES system. The control structure of DC–AC microgrid integrated with BES system is proposed, and the study is extended to explore the mechanism of demand side management (DSM) with the incorporation of voltage-droop characteristics. The BES system is interlinked to maintain the voltage to a desirable range and the proposed work is intended to show the introductory concept on DSM accomplished through voltage-reduction at the consumption-side. The proposed control strategy not only achieves frequency-regulation in adherence to IEEE Standard-1547, but also maintains customers' quality of service while customizing voltage for regulating DSM. The basis of regulating the nickel-metal-hydride battery is state-of-charge of BES system and voltage generated by the hybrid sources consist of photovoltaic and wind energy systems. The adequacy of the proposed control scheme with BES-module is validated using time-domain simulation studies considering voltage-dependent-loads. [ABSTRACT FROM AUTHOR]

Standalone PhotoVoltaic System (SPVS) performance is heavily dependent on the DC-bus voltage. A robust control of the DC-bus voltage results in a good stable-working system. This paper presents a new strategy, of controlling the different elements of the system, that helps to regulate the DC-bus voltage against abrupt load variation, and keeps the system working effectively even during the lack of batteries. It uses Sliding Mode Controllers (SMC) for DC-DC converters to improve the dynamic performance of the PV system. It protects the batteries by using them only when they are needed, and therefore extends the lifetime of the installation. The system is designed to supply both DC and AC loads in remote sites where no grid utility is available. It is composed of three photovoltaic arrays, a bank of batteries, a set of DC-DC and DC-AC converters, and DC/AC loads. The operations of the system are categorized into 04 modes, and their selection depends on the supply and demand of energy on one side, and the state of charge of the batteries on the other. The system is modeled and simulated in Simulink environment. Tests are done under very hard and quick variations of load, and results bear witness to the robustness of the controllers and to the high performance of the system as well. [ABSTRACT FROM AUTHOR]

Control, sizing and management of stand-alone or grid-connected photovoltaic (PV) plants are based on static methods, energy estimation and simulations of the PV systems in average conditions. Despite the fact that these approaches provide information about the expected performances, they do not perform an optimization of the PV plant; nor do they allow an optimal matching of PV-load association for the local climate conditions. Besides that, the problems of the PV cost, the maintenance and the battery replacements remain an obstacle for the development of PV plants. To surmount these problems (storage, control, cost and efficiency), we have developed in our laboratory new prototypes of less battery storage systems (LBSS), which substitute the battery storage by a thermal storage for PV refrigeration or a hydraulic storage for PV pumping and water desalination (Cherif. A. (1994). Optimization and management of new PV refrigeration plant using latent storage. In Proceedings of the 12th E.P.S.E. Conference, Amsterdam, Vol. 1, HS Stephens & Associates, pp. 448-452). This approach will contribute to reduce the maintenance operations, the PV cost and the breakdowns of the battery and its regulator. We have introduced a new control strategy based on the performance of the DC/DC and DC/AC converters and the real time monitoring of the PV plant. This paper presents the technical and experimental aspects of these LBSS systems. [ABSTRACT FROM AUTHOR]