1,720,990 research outputs found
Advanced forecasting method to the optimal management of a DC microgrid in presence of uncertain generation
No full textThis paper proposes a model to the optimal management of a complex DC microgrid with advanced forecasting method for photovoltaic generation. The strategy is aimed at minimizing the daily total energy cost using a very short-time predictive control procedure. At first, the predicted power of the renewable generation unit is obtained by using an innovative forecasting approach based on the Bayesian technique and Monte Carlo No-U-Turn Sampler method; at a later stage, the predicted power and all the relevant parameters are introduced in a solver for the optimization problem developed in Python language. Finally, the goodness of the model is tested introducing a significant case study. © 2015 IEEE
Innovative Frequency Controls for Intelligent Power Systems
No full textThis paper presents a new controller for the frequency control in interconnected power systems based on control schemes developed in the European ELECTRA IRP project. Running three functions (Adaptive Frequency Containment Control, Balance Restoration Control and Secondary Control), the proposed solution solves locally the instability problems by using local resources. When an imbalance occurs, the Adaptive Frequency Containment Control and the Balance Restoration Control, working at the same time scale, stabilize the area under control while Secondary Control restores the frequency to the nominal value. © 2018 IEEE
Frequency stability in microgrid: Control strategies and analysis of BESS aging effects
No full textIn order to ensure a thorough analysis, all components placed in a microgrid would have to be considered to guarantee an effective energy management. To this aim, various algorithms are used both to preserve and restore power systems after significant disturbances. However, these models frequently do not evaluate components performance decline with the age and, consequently, they don't consider actual values during microgrid analysis, potentially affecting obtained results. In particular, evaluating energy storage systems aging and their effects has rarely been addressed in prior works. The present article proposes a model to maintain power system/microgrid stability after disturbances using a load shedding algorithm that also consider storage system aging effects. Furthermore, our scheme estimates when the microgrid system begins to suffer for the energy storage aging. © 2016 IEEE
Independent energetic grids for a smart island: Model and design of a microgrid for a small Italian island
No full textUnlike many Italian peninsular areas, which are increasingly turning to a diverse supply of renewable resources to generate electricity, Italian not-interconnected small islands continue to rely on oil for their electricity and other energy needs (e.g. transports). Small-scale electricity systems, that are not connected to a larger electricity grid, are usually more expensive. The present paper proposes the functional design of an innovative Smart Grid which allows changing an Italian small not-interconnected island, Pantelleria, into a smart island, towards a more sustainable energy model. In detail, a techno-economic feasibility study is performed in order to design a Smart Grid at Pantelleria Island. The study identifies innovative architectures and characteristics of the main components of the Smart Grid as well as the characteristics both in quantitative and qualitative terms of the renewable energy technologies and electric storage systems to be installed in order to reduce the dependence on fossil energy sources and activate the distribution network of the island. © 2016 AEIT
A novel multi-objective design tool for multilevel converters by an electro-thermal evolutionary approach
No full textMultilevel converters will be one of the most important conversion systems in future power networks. These technologies can facilitate the integration of flexible DER in the grid also getting a significant role in microgrids. Designing high performances converters is not a trivial task due to the numerous different variables involved in the design process. This paper proposes a novel design approach and an easy-to-use executable program, employing a graphical user interface, dedicated to the design of multilevel converters. This software tool aims to obtain multilevel trade-off solutions in terms of efficiency, Mean Time Between Failure and price. The core of this tool consists in a multi-criterion optimization technique, based on the use of an evolutionary genetic algorithm, matched to accurate circuital models (i.e. electro-thermal reliable routine - TER and multilevel converter price routine). The solutions, plotted in two-dimensional and three-dimensional graphics, allow to easily choose the optimal solution for the specific context and visualize the corresponding bill of materials (BOM). The software also permits to consider innovative converter systems employing novel switching devices as the silicon carbide and the gallium nitride types
Congestion Management in distribution grid networks through active power control of flexible distributed energy resources
No full textWith the increasing penetration levels of distributed energy resources (DER), grid congestion events may occur by causing severe damages and potential black outs in power systems. Developing innovative operation planning strategies and control tools for the grid congestion management is thus a primary goal for ensuring network reliability and security. In this paper, we propose a Grid Congestion Management Controller (GCMC) to solve grid congestion issues by controlling the active power of flexible DER (e.g. storage, flexible loads, electric vehicles, distributed generators) present in the grid, thus increasing availability of active resources to maintain the network stability. The GCMC is developed here as a self-contained control acting on distribution level, and will be further developed to be integrated in the INTEgrated opeRation PLANning tool, which will be the main outcome of the INTERPLAN H2020 project. INTERPLAN (Nov.2016Nov.2020) aims to provide an integrated tool to support transmission system operators and distribution system operators in the operation planning of the pan-European network. The GCMC effectiveness is tested in the presence of specific congestion events by using the Cigrè benchmark grid model under different scenarios. Simulation results show that the proposed control logic is efficient in mitigating grid congestion through optimally re-dispatching active power variation to the flexible DER connected to each busbar in the network
Innovative software for reliability, resilience, security and adequacy assessment of AC and DC grids and microgrids
No full textThe huge presence in a carbon free energy system of the non-programmable renewable generation sources, their thermal load and mobility electrification determine issues and criticalities in continuous power systems operations. In such context, electricity security becomes a challenging task to be assured. Available software permits to singularly evaluate AC networks security, adequacy, reliability, and resilience features but a holistic approach it is still lacking. In addition, models and methods are developed only for AC power systems and they are not still implemented for DC and hybrid AC/DC grids. In this paper, authors propose an innovative software permitting to analyze, for AC, DC and hybrid electrical systems, power system security, adequacy, resilience, and reliability by an integrated approach. The proposed open-source software was implemented taking advantage of Python Programming Language and it is an open-source product of 'Evolution, planning, management and electricity networks operation' project
Innovative Method for Reliability Assessment of Power Systems: From Components Modeling to Key Indicators Evaluation
Full text linkPower systems comprise different electrical, electronic, electromechanical and electrochemical components. Adequacy, security, resilience and reliability represent essential requirements for grids functioning mode. The evaluation of such aspects can constitute a delicate task in the presence of heterogeneous components. Focusing on reliability assessment, several Reliability Prediction Models are available. They are suitably applied according to the type of component under evaluation. The lack of homogeneity of these models forbids the comparison of performance and identification of unreliable systems and grid section. This paper aims to face the mentioned issue proposing a unique reliability assessment methodology able to characterize different equipment connected to radial/meshed/ring grids and subjected to different stressing and ageing factors. It is customized for electrical lines, transformers, circuit breakers, converters and renewables plants. Component and systemic key indices are calculated. Furthermore, a novel “load feeding reliability“ indicator is evaluated for providing information about the supply reliability of a specific load. This index is meaningful for the identification of unreliable grids, microgrids and systems. Such an approach can contribute to improve power systems design, planning and control. The proposed method is integrated in a software application implemented for grid reliability assessment. The obtained results are reported for an urban grid including an underground transportation area
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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