1,721,021 research outputs found
A Security-Constrained Islanding Feasibility Optimization Model in the Presence of Renewable Energy Sources
No full textThe massive integration of Renewable Energy Sources (RES) into power systems is a major challenge but it also provides new opportunities for network operation. For example, with a large amount of RES available at HV subtransmission level, it is possible to exploit them as controlling resources in islanding conditions. Thus, a procedure for off-line evaluation of islanded operation feasibility in the presence of RES is proposed. The method finds which generators and loads remain connected after islanding to balance the island's real power maximizing the amount of supplied load and assuring the network's long-term security. For each possible islanding event, the set of optimal control actions (load/generation shedding) to apply in case of actual islanding, is found. The procedure is formulated as a Mixed Integer Non-Linear Problem (MINLP) and is solved using Genetic Algorithms (GAs). Results, including dynamic simulations, are shown for a representative HV subtransmission grid
Integrated European intra-day electricity market: Rules, modeling and analysis
Full text linkCurrently, the coupling of the European Electricity Markets has been fully achieved for the Day-Ahead Market. In the same time, a joint integrated Intra-Day Market based on the Continuous Trading mechanism is under implementation and it involves countries from West of Europe. However, some countries (e.g. Italy and Iberian countries) use the Discrete Auction mechanism and their integration implies the harmonization of the two trading mechanisms. A Hybrid Mechanism that represents the coordination of Continuous Trading and Discrete Auction has been discussed with two concrete proposals being made by Italy and Iberian countries. Thus, the aim of this paper is to propose an advanced algorithm which can simulate the clearing of the integrated European Intra-Day Market with any levels of coordination between Discrete Auction and Continuous Trading. The proposed model is formulated as a Mixed Integer Linear Problem and incorporates all market rules of both mechanisms. The algorithm is flexible enough to adapt to future changes. In addition, a case study that considers the current and near future market participants and covers an entire day of an Intra-Day Market is run by an iterative process to investigate the impact of the hybrid Intra-Day Market model on the Iberian countries and Italy according to their proposals. Moreover, the test cases represent realistic data in terms of number of variables and constraints, and in terms of complexity of the bids. The results of the paper show that, on one hand, the proposed market clearing model can be applied for different levels of Continuous Trading and Discrete Auction coordination and, on the other hand, the integration into the single European Intra-Day Market of Italy and Iberian countries can be beneficial for them. Therefore, the general conclusion is that the proposed market clearing model can be successfully used by the Power Exchanges currently integrated to solve the market or by the Power Exchanges not yet integrated to evaluate the impact of their future integration. On the other hand, the model can easily cope with any further changes in the market rules and represents a tool for future research, e.g. analysis of market participants behavior in future scenarios or evaluation of various financial instruments to manage the congestion of intra-border interconnectors
Verso le Supergrid: il caso irlandese
No full textGli obiettivi di politica energetica dell’UE al 2050 impongono la necessità di sfruttare siti di generazione da fonte rinnovabile caratterizzati da elevata potenza disponibile ma distanti dai centri di carico. Ciò pone nuove sfide per la realizzazione di “autostrade” per l’energia elettrica, le Super Grid
Hosting Capacity Analysis: A Review and a New Evaluation Method in Case of Parameters Uncertainty and Multi-Generator
Full text linkThe rapid growth of distributed energy resources exploitation can cause voltage violations and overloading on distribution grids due to the uncontrolled and unprogrammable power injections associated with dispersed generators. To overcome these issues, distributed system operators have to evaluate the maximum generation that can be hosted by distribution grids without violating the technical constraints and find the ways to increase it. In this paper, different methodologies for hosting capacity evaluation are reviewed, and a novel model to determine the hosting capacity considering grid parameters uncertainties and multi-generator connection is proposed
A new modeling and placement of shunt FACTS devices in the secondary voltage regulation environment
Full text linkTwo-stage coordinated scheduling of hydrogen-integrated multi-energy virtual power plant in joint capacity, energy, and ancillary service markets
No full textWith the emergence of distributed resources (DRs), developing an effective, profitable, and green management method is of great importance. Virtual power plant (VPP) can aggregate various DRs, optimize their schedules, and participate in electricity markets uniformly to earn profit. The optimal scheduling problem in spot market has been widely studied, however, few studies have extended the services of VPP to the long-term scale. This paper proposes a coordinated scheduling method for a multi-energy virtual power plant (MEVPP), considering the integration of hydrogen facilities. A holistic market framework, including capacity market, energy market (EM), and ancillary service market (ASM) is developed jointly for the coordination among the annual capacity schedule, daily energy schedule, and daily reserve schedule of MEVPP. A hybrid hydrogen storage system including daily hydrogen storage and seasonal hydrogen storage is modeled to achieve both intraday and cross-seasonal peak shaving. Stochastic programming is used to tackle the uncertainties and risk management is considered by conditional value at risk. With the help of numerical analysis in case studies, it can be concluded that the proposed coordinated scheduling method can improve the economy of MEVPP. The profit from joint market decreases the total cost by about 52 %. The capacity adequacy and flexibility of MEVPP can be improved by the coordination of capacity and reserve services. The hybrid hydrogen storage system can realize the efficient integration of hydrogen and increase hydrogen production and consumption by about 9 %
A thorough comparison among various mathematical approaches to compute PUN in Italy
No full textToday, the coupling of Day-Ahead Market in Europe is extensively studied. One of the challenges of the market clearing model is the National Uniform Price used in Italy and known as PUN ('Prezzo Unico Nazionale') as it introduces nonconvexity in the model resulting in high computation time. In literature, various proposals are made to efficiently find the PUN; among them, the most promising are the iterative procedure and complementarity theory. The goal of the paper is to re-formulate these approaches and compare them to identify their advantages and disadvantages. Tests are made on the real data obtained from the official websites for 10th -15th of March, 2016
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