Robust 24 Hours ahead Forecast in a Microgrid: A Real Case Study

Forecasting the power production from renewable energy sources (RESs) has become fundamental in microgrid applications to optimize scheduling and dispatching of the available assets. In this article, a methodology to provide the 24 h ahead Photovoltaic (PV) power forecast based on a Physical Hybrid Artificial Neural Network (PHANN) for microgrids is presented. The goal of this paper is to provide a robust methodology to forecast 24 h in advance the PV power production in a microgrid, addressing the specific criticalities of this environment. The proposed approach has to validate measured data properly, through an effective algorithm and further refine the power forecast when newer data are available. The procedure is fully implemented in a facility of the Multi-Good Microgrid Laboratory (MG(Lab)(2)) of the Politecnico di Milano, Milan, Italy, where new Energy Management Systems (EMSs) are studied. Reported results validate the proposed approach as a robust and accurate procedure for microgrid applications

Integration, control and optimization of the solar photovoltaic-battery system in microgrids

This document composes the work realised and the research results developed within the scope of electric energy storage at the Renewable Energy Chair of the University of Évora. The current legal and technological framework of electrochemical energy storage technologies is reported, and its framework is demonstrated in the Portuguese and European contexts. Next, the experimental microgrid that comprises several electric energy storage technologies is described. The lithium-ion and vanadium redox flow technologies were tested and characterized for later validation of the electrical models that describe their performance. A state-of-the-art review allowed the experimentation of energy management strategies that fit the technologies studied, allowing smarter management in residential and services sectors. In this thesis, management algorithms, battery models, and an indication of technical, economic and energy parameters were combined in a tool to study the simulation of the operation of these technologies, allowing to define different operating objectives, fine-tune parameters and even join the operation of different technologies. This work was accompanied by national and international projects, attempting to respond to existing problems in the operation of real systems and gaps identified in the design phase, such as a robust dimensioning tool, with the integration of different battery managing methods; Integração, controlo e otimização do sistema solar fotovoltaico-bateria em microrredes Resumo: Este documento compõe o trabalho realizado e respetivos resultados da investigação desenvolvida no âmbito do armazenamento de energia elétrica na Cátedra Energias Renováveis da Universidade de Évora. Os atuais enquadramentos legais e tecnológicos das tecnologias eletroquímicas de armazenamento de energia são relatados, nos contextos português e europeu. Seguidamente, uma microrrede experimental que inclui diversas tecnologias de armazenamento de energia elétrica é descrita. As tecnologias de fluxo redox de vanádio e de iões de lítio foram objeto de ensaio e caracterização, para posterior validação dos correspondentes modelos que descrevem a sua performance elétrica. A revisão do estado da arte permitiu a experimentação de estratégias de gestão de energia que se adequam às tecnologias estudadas, que permitam a sua gestão inteligente, no contexto residencial e de serviços. Nesta tese, os algoritmos de gestão, os modelos das baterias, a indicação de parâmetros técnicos, económicos e energéticos foram combinados numa ferramenta para estudo da simulação da operação destas tecnologias permitindo definir diferente objetivos, afinar parâmetros e até operar conjuntamente diferentes tecnologias. Este trabalho foi acompanhado pelo paralelismo de projetos nacionais e internacionais, tentado dar resposta a problemas existentes na operação de sistemas reais, e lacunas identificadas na fase de projeto, tal como uma ferramenta de dimensionamento robusto, com a integração de diferentes formas de gerir baterias

Optimization of Solar Photovoltaic-Based Microgrid for Sustainable Energy Planning in Bajoe Port, Bone Regency, South Sulawesi: A Case Study

Electrification in rural areas is still inadequate due to the limitations of the main power grid. Therefore, harnessing available renewable energy sources, such as solar energy, is an appropriate solution. The solar photovoltaic (PV) system can be utilized either in connection with the main power grid or in standalone mode (islanded) and can be supported by other power generation sources through a microgrid approach to enhance reliability. This research focuses on the design of a power system backed by a single renewable energy source, based on Photovoltaic (PV) technology, for the administrative building and passenger waiting area of Bajoe Port in Bone Regency. The microgrid technology is applied to improve the reliability and continuity of the electricity supply. The limited power supply at the site will be addressed using a microgrid system that combines power from the main grid, PV modules, and emergency generators. The system modeling takes into account the sensitivity of global climate conditions and local load requirements. The HOMER Pro software is utilized as a simulator to optimize the designed system. The PV module, with an array area of 186.92 m2, will be installed in the parking area of Bajoe Port, which covers an area of 3,264.3 m2. The best result for the PV system design within the microgrid system, with a capacity of 41.5 kWp, yields an electricity output of 180,451 kWh per year based on the local average solar irradiation of 5.05 kWh/m2/day. The economic evaluation, expressed in terms of Net Present Cost (NPC) amounts to Rp. 421,251,000, with a Cost of Energy (COE) of 126.04/kWh. Moreover, the system can contribute 110,305 kWh/year to the main grid operated by the state-owned utility, Perusahaan Listrik Negara (PLN). Simulation results indicate that the designed PV microgrid system can contribute to the local daily electrical load, with a daily power requirement of 117.78 kWh and excess energy being sold to the PLN grid

Power Quality Enhancement in Electricity Grids with Wind Energy Using Multicell Converters and Energy Storage

In recent years, the wind power industry is experiencing a rapid growth and more wind farms with larger size wind turbines are being connected to the power system. While this contributes to the overall security of electricity supply, large-scale deployment of wind energy into the grid also presents many technical challenges. Most of these challenges are one way or another, related to the variability and intermittent nature of wind and affect the power quality of the distribution grid. Power quality relates to factors that cause variations in the voltage level and frequency as well as distortion in the voltage and current waveforms due to wind variability which produces both harmonics and inter-harmonics. The main motivation behind work is to propose a new topology of the static AC/DC/AC multicell converter to improve the power quality in grid-connected wind energy conversion systems. Serial switching cells have the ability to achieve a high power with lower-size components and improve the voltage waveforms at the input and output of the converter by increasing the number of cells. Furthermore, a battery energy storage system is included and a power management strategy is designed to ensure the continuity of power supply and consequently the autonomy of the proposed system. The simulation results are presented for a 149.2 kW wind turbine induction generator system and the results obtained demonstrate the reduced harmonics, improved transient response, and reference tracking of the voltage output of the wind energy conversion system.Peer reviewedFinal Accepted Versio

Modeling a Grid-Connected PV/Battery Microgrid System with MPPT Controller

This paper focuses on performance analyzing and dynamic modeling of the current grid-tied fixed array 6.84kW solar photovoltaic system located at Florida Atlantic University (FAU). A battery energy storage system is designed and applied to improve the systems stability and reliability. An overview of the entire system and its PV module are presented. In sequel, the corresponding I-V and P-V curves are obtained using MATLAB-Simulink package. Actual data was collected and utilized for the modeling and simulation of the system. In addition, a grid- connected PV/Battery system with Maximum Power Point Tracking (MPPT) controller is modeled to analyze the system performance that has been evaluated under two different test conditions: (1) PV power production is higher than the load demand (2) PV generated power is less than required load. A battery system has also been sized to provide smoothing services to this array. The simulation results show the effective of the proposed method. This system can be implemented in developing countries with similar weather conditions to Florida.Comment: 6 pages, 14 figures, PVSC 201

Additional controls to enhance the active power management within islanded microgrids

Balancing the generated and consumed power in a microgrid is highly affected by the varying output power of the intermittent, renewable energy-based, distributed energy resources. This paper focuses on coordinating the output power among the energy resources within a microgrid while managing the consumed power at the demand side. The considered microgrid in this study consists of a battery system, which is the primary unit for grid-forming, as well as a photovoltaic system as the grid-following unit. A soft starting ramp function and an active power reduction function are implemented within the photovoltaic inverter respectively for the periods after the isolation of the microgrid from the grid and the over-frequency observation. Meanwhile, a demand-side management is developed based on the level of the battery’s state of charge, to facilitate the microgrid with a longer time in supplying its critical loads

RELIABILITY AND RESILIENCE EVALUATION OF A STAND-ALONE MOBILE MICROGRID-ANALYSIS AND EXPERIMENTAL MEASUREMENTS

As the Department of Defense (DOD) deploys renewable distributed energy resources (DERs) to reduce fossil fuel consumption, microgrids are being evaluated as one way to generate and deliver reliable electric power to stationary and mobile military units. Commercial off the Shelf (COTS) microgrid components are a viable cost-effective option to setup stand-alone microgrid systems to support mobile military units and help drive the transition to a more sustainable yet energy-resilient military. Reliability and resilience are key parameters in determining the effectiveness of microgrids in supporting military missions. Although in the past few years many researchers have presented reliability and resilience models of various complexity, experimental measurements and model validation are not available in the literature for mobile COTS microgrids. The goal of this thesis research is to experimentally assess the reliability and resilience of stand-alone, mobile microgrids that can be carried by one or two individuals and can be easily assembled in the field in support of operations in locations where utility power is not available. Utilizing COTS DERs including batteries, PV arrays and power converters, three different standalone microgrid architectures were designed, analyzed, and tested in the laboratory. Reliability block diagrams, and system fault trees were created per MIL-HDBK-338B, to compare the reliability of the three microgrid configurations.Major, United States Marine CorpsApproved for public release. Distribution is unlimited