1,720,986 research outputs found
Competitive and Cooperative Approaches to the Balancing Market in Distribution Grids
No full textThe electrical grid has been changing in the last decade due to the presence, at the distribution level, of renewables, distributed generation, storage systems, microgrids, and electric vehicles. The introduction of new legislation and actors in the smart grid’s system opens new challenges for the activities of companies, and the development of new energy management systems, models, and methods.
In order to face this revolution, new market structures are being defined as well as new technologies and optimization and control algorithms for the management of distributed resources and the coordination of local users to contribute to active power reserve and ancillary services.
One of the main problems for an electricity market operator that also owns the distribution grid is to avoid congestions and maximize the quality of the service provided.
The thesis concerns the development and application of new methods for the optimization of network systems (with multi-decision makers) with particular attention to the case of power distribution networks
This Ph.D. thesis aims to address the current lack of properly defined market structures for the determination of balancing services in distribution networks. As a first study, to be able to handle the power flow equation in a computationally better way, a new convex relaxation has been proposed. Thereafter, two opposite types of market structure have been developed: competitive and cooperative. The first structure presents a two-tier mechanism where the market operator is in a predominant position compared to other market players. Vice versa in the cooperative mechanism (solved through distributed optimization techniques ) all actors are on the same level and work together for social welfare.
The main methodological novelties of the proposed work are to solve complex problems with formally correct and computationally efficient techniques
Distributed Model Predictive Control for Building Automation systems: a parallel ADMM approach
No full textThis paper proposes a distributed Model Predictive Control (MPC)-based approach for comfort temperature tracking and electric consumption minimization in building automation systems (BASs). The developed optimisation model and overall architecture were designed with real-world applications in mind, incorporating in-field controllers and sensors. A distributed optimization algorithm is here proposed, which extends the well-known alternating direction method of multipliers (ADMM) to handle inequality constraints (that are necessary to model the typical local temperature sensors and actuators in smart buildings). The
methodology is validated through testing on a real case study,
namely the Smart Energy Building (SEB) at the Savona Campus
of the University of Genoa, which is characterised by a geothermal heat pump, photovoltaics, storage systems, and charging stations. The algorithm enables reaching a comfortable temperature, limits power variation for the heat pump, and minimises costs. Regarding other solution methods, comparison with state-of-the-art approaches demonstrates a 25% reduction in the number of iterations needed for convergenc
Optimal Scheduling and Control of a Fuel Cell-based Microgrid using a Reference Governor Approach
No full textAn unconstrained optimization approach to the stochastic traffic assignment with electric vehicles
No full textA Multilevel Optimization Model for a Distribution Power Grid with the Active Participation of Electric Vehicles Via Aggregators
No full textThis paper formalizes a multi-level optimization problem for a distribution power grid. The grid is set up with Electrical Vehicles (EVs) to minimize the total energy cost and satisfy different loads distributed in the grid. At the higher level, the Distribution System Operator (DSO) must deal with a Balancing Market to minimize costs. Instead, at a lower level, Electrical Vehicle Aggregators (EVAs) aim at controlling the charging and discharging of Electrical Vehicles (EVs) maximizing their profit. The optimization problem of EVAs is solved analytically through KKT (Karush-Khun-Tucker) conditions and inserted into the DSO optimization problem. The complete optimization model has been implemented and tested in the IEEE 13-bus system. The results show that the proposed bi-level model significantly reduced the variation of peak consumption by 64.56% and the power cost by 3.07%
A hierarchical Building Management System for temperature's optimal control and electric vehicles' integration
No full textA bi-level building management system for optimal temperature control and scheduling of electric vehicles in a smart building is proposed. The architecture allows considering automated decisions, both for operational management and real-time control, minimizing costs and the dissatisfaction of different requirements (electric vehicles' charging, demand response). A particular feature of the building management system is that it includes a model for electric vehicles' charging (both for vehicles-to-grid and classical electric vehicles) that can consider three-phases unbalanced systems and the inputs required by the Charging Stations, i.e., the set point for the current for each plugin use. Moreover, a distributed approach for the optimal control of fan coils is proposed that allows adjusting the temperature in each room. The developed building management system has been tested at the Savona Campus in a building characterized by a photovoltaic field, a geothermal heat pump, EVs charging infrastructure, thermal storage, and a fan coil circuit. The tests carried out at the Campus show that the proposed algorithm allows a reduction of the daily costs of about 20% with respect to a simple heuristic, without compromising the fulfillment of the charging requests of the electric vehicles. The savings can be increased till close to 35% if a demand response is also exploited
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
An architecture for the optimal control of tertiary and secondary levels in small-size islanded microgrids
No full textIslanded microgrids are assuming a key role for the support in the distribution grid's management, which is more and more difficult due to the massive increase of distributed generation and energy production plants from renewable resources. In this paper, a new architecture for the optimal control of tertiary and secondary levels in small-size islanded microgrids is proposed. Specifically, at each optimization step, by using a receding horizon approach, the tertiary control provides the optimal power schedule for the microgrid on the basis of economic and environmental criteria. Then, the secondary control, to provide set points for primary control, uses another objective function that minimizes the quadratic deviation from the reference values provided by the tertiary level and the desired frequency for good performances. The approach is applied to a real case study (a portion of the Savona Campus Smart Polygeneration Microgrid) characterized by a diesel engine connected to a synchronous generator, a photovoltaic plant, and an electrical storage system
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