1,721,063 research outputs found
Frequency dynamics of power systems with temporally distributed disturbances
No full textThe frequency dynamics and stability of power systems is essentially affected by nature and characteristics of the disturbances occurring in the system. Conventionally, frequency transients are examined assuming a single disturbance applied at a given time. However, actual incidents in the power systems can be generally composed of a temporal sequence of events, and thus characterized by multiple power imbalances of different magnitudes and time offsets. The consideration of the effects of the temporal distribution of power imbalances is important for two main reasons: the impact on the frequency dynamics of the system in terms of frequency metrics such as minimum instantaneous frequency and maximum absolute rate of change of frequency, and the correct representation of the dynamic behaviour of the system also for complex events such system separation. The work provides an analytical approach for the theoretical study of the frequency dynamics with temporally distributed power imbalances. The analytical approach is then used to examine the impact of multiple disturbances having different magnitudes and time offsets on the typical frequency metrics used to characterize the transient performances of the system. The concepts derived in the work are finally applied to the case of an actual event occurred in the Continental Europe power system, showing the fundamental role of considering temporally distributed power imbalances for a correct and accurate assessment of the dynamics of the system
Economic Dispatch Problem Solution Via Holomorphic Embedding Method on IEEE 14-Bus System for Different Loading Scenarios
Full text linkThis paper presents an approach for solving the Economic Dispatch Problem (EDP) in power systems considering transmission losses in a recursive manner via a Holomorphic Embedding Method (HEM) applied to the IEEE 14 Bus system and tested for different loading scenarios. The HEM methodology has been proposed recently in power system to solve the power flow problem. The technique was adapted in this work for solving directly the nonlinear equation system that arises when the EDP lossy optimization problem is formulated. In order to validate the method three different loading scenarios were created to observe the method's response to systems with a diverse computational and mathematical demand. In order to demonstrate the efficacy of the approach, experiments are carried out employing the Matlab platform. The performance of the proposed technique is evaluated by using the classical Newton-Raphson (NR) method. The methodology presents similar results compared to the NR method, however having higher performance when compared in terms of convergence
How Blockchain Technology Can Address Circularity and Trace Emission in the Energy Sector
Full text linkThis paper outlines the European perspective on circularity in the energy sector and details how blockchain could support it. Moreover, while the need for raw materials and e-fuels is increasing (due to the economic, industrial, and societal ecological transformation to slow down the pace of climate change), their supply becomes more and more risky. Therefore technologies to support tracing and certification are on the spot. To achieve resilience to new threats, Europe is pointing at circularity in all fields. Circularity requires the need for tracing substances and devices, food, and products, to retrieve and recycle as much as possible. Else than the need to limit the exploitation of the planet’s resources and thus stay within the planetary boundaries, circularity is tightly connected to strategic dependencies from highly unstable or politically distant countries. This issue is further aggravated by the Russia-Ukraine crisis. Digital technologies, like Distributed Ledger Technologies, can well support the implementation of circularity in many fields. The paper identifies challenges and proposes potential solutions related to the implementation of circularity. It also explores the application of circularity principles in the energy sector, with a focus on energy communities. Energy communities involve local stakeholders coming together to generate, consume, and manage renewable energy collectively. Overall, the paper provides insights into the European perspective on ecological transition, highlighting the importance of systemic transformation, resilience, and circularity in addressing climate change and achieving sustainability goals. It explores the role of digital technologies, such as Distributed Ledger Technologies (DLTs), in supporting circular practices and discusses specific applications in the energy sector
Optimal nanogrid planning at building level
Full text linkThis paper presents a planning framework for active buildings as an Energy Nano-Grid (ENG), determining the optimal size and generation mix of distributed energy resources (DERs) and battery energy storage (BES) system, the type of ENG that can be either AC or DC, and the optimal energy management (EM). Due to the increasing penetration of battery energy storage devices, electric vehicles (EVs) and even DC loads on the utility side, DC ENGs would potentially be more useful than AC ENGs by reducing the number of converters, facilitating the connection of various types of distributed energy resources and loads to the common bus with simplified interfaces, and mitigating the losses associated with AC/DC energy conversion. Therefore, the selection of the type of ENG is an economic issue where the planning objective includes the investment, operation and maintenance costs of energy resources, the investment costs of battery energy storage (BES) and converters, and the costs/revenues for buying/selling energy from/to the upstream grid or neighbor ENGs. In this way, the proposed program achieves an optimal load sharing. Optimal results might be affected in terms of some system specifications such as the ratio of DC load (from 0.4 to 1) at ENG, the maximum permissible installation capacity of BESs (from 200 to 800 kWh), and maximum discharge power that EVs can deliver to the ENG or upstream network (from 50 to 200 kW). Using some numerical case studies associated with three residential ENGs, result show that increase in the rate of DC load has the highest effect on the type of ENG (DC feeder is adopted for DC load rate 0.6 at ENG 1 and ENG 2, and 0.8 at the third one) through decrease in investment and operation costs, meanwhile, the capacity of BES directly affect the size of generation units, and the maximum discharging power of EVs just support peak load supply due to being out of the park lot during the day. The proposed planning model is analyzed in detail to demonstrate its applicability, effectiveness and control
A Technical Approach to the Energy Blockchain in Microgrids
Full text linkThe present paper considers some technical issues related to the “energy blockchain” paradigm applied to microgrids. In particular, what appears from the study is that the superposition of energy transactions in a microgrid creates a variation of the power losses in all the branches of the microgrid. Traditional power losses allocation in distribution systems takes into account only generators while, in this work, a real-time attribution of power losses to each transaction involving one generator and one load node is done by defining some suitable indices. Besides, the presence of P-V nodes increases the level of reactive flows and provides a more complex technical perspective. For this reason, reactive power generation for voltage support at P-V nodes poses a further problem of reactive power flow exchange, that is worth of investigation in future works in order to define a possible way of remuneration. The experimental section of the paper considers a Medium Voltage microgrid and two different operational scenarios
Efficientamento energetico di utenze domestiche nelle isole minori italiane
No full textL’articolo tratta l’efficientamento energetico nel settore residenziale delle piccole isole non connesse alla rete di trasmissione elettrica nazionale. L’analisi ha riguardato un’utenza tipo dell’Isola di Lampedusa, individuata sulla base dei dati statistici ISTAT, di cui sono stati acquisiti i dati di consumo da bolletta e monitorati i consumi elettrici al fine di selezionare gli interventi di retrofit più adeguati. Fra questi vi sono: la sostituzione degli scalda-acqua elettrici esistenti e il ricorso a tecnologie di Building Automation Control system (BACs) per la gestione dell’impianto di illuminazione e di altri carichi elettrici flessibili. La valutazione dei risparmi conseguibili è stata effettuata mediante simulazioni in regime dinamico. Ciò ha messo in evidenza come i migliori risultati si ottengono ricorrendo ad un impianto solare termico per la produzione di ACS con un risparmio mensile medio del 39% e utilizzando BACs sull’impianto di illuminazione con contestuale sostituzione degli apparecchi illuminanti con tecnologia a LED con un risparmio del 27%. Si è potuto inoltre verificare che tali azioni di retrofit consentono anche una riduzione dei picchi di prelievo nel diagramma di carico giornaliero determinando un beneficio per la rete di distribuzione dell’isola e per il sistema di generazione elettrico interamente oggi basato su generatori diesel
Power system dynamic analysis in future energy scenarios with high penetration of renewable energy sources — case study: Sicilian electrical grid
No full textIn the near future, Sicily will undergo an unprecedented penetration of renewable sources in its electricity generation mix. In response to these developments, several grid enhancement initiatives have been planned, including HVDC infrastructure and interconnections with foreign systems. This paper presents the results of dynamic studies on 2030 energy scenarios developed by the Italian institute Ricerca Sistema Energetico (RSE). These studies consider severe contingencies and evaluate various combinations of regulating resources, both traditional and innovative, including Grid Forming control. The results indicate that relying solely on traditional regulation during contingencies leads to instability, emphasizing the urgent need to involve all available resources in the power system's regulation mechanisms. Among the most interesting findings is the case of the Grid Forming control applied to the Tyrrhenian Link: even in the absence of regulation from the renewable sources present on the island, this approach successfully keeps the frequency drift within the permissible 1.5 Hz range. This demonstrates the significant strategic value of the infrastructure when deployed to provide dynamic support to the power system
Assessing the Grid Impact of Renewable Energy Communities in a Small Island
No full textThe paper presents a study carried out on the island of Pantelleria aimed at assessing the impact of the rise of renewable energy communities (RECs) on the distribution grid parameters. A comparison of various scenarios is done considering different operational strategies of BESSes and electric storage water heaters and different penetration of photovoltaic systems, whose maximum power is defined according to the Italian requirements for small islands (Decree “Isole minori”). The analysis of the impact on the grid is a key element for the evolution and development of RECs in small islands. The study highlight the beneficial impacts of RECs on the distribution grid if associated with suitable Demand Response strategies
Driven primary regulation for minimum power losses operation in islanded microgrids
Full text linkThe paper proposes an improved primary regulation method for inverter-interfaced generating units in islanded microgrids. The considered approach employs an off-line minimum losses optimal power flow (OPF) to devise the primary frequency regulation curve’s set-points while satisfying the power balance, frequency and current constraints. In this way, generators will reach an optimized operating point corresponding to a given and unique power flow distribution presenting the minimum power losses. The proposed approach can be particularly interesting for diesel-based islanded microgrids that face, constantly, the issue of reducing their dependency from fossil fuels and of enhancing their generation and distribution efficiency. The Glow-worm Swarm Optimization (GSO) algorithm is selected as a key heuristic tool for solving the optimization problem. The main program is carried out in Matlab environment. A case study with a parametric analysis is implemented and all results are assessed and compared with the conventional droop control method to show the effectiveness of the proposed method as well as the improved reliability of the system
THE OPPORTUNITY OF GRID-FORMING CONVERTERS IN THE WIDE-AREA CONTROL OF POWER SYSTEMS
No full textIn conventional wide-area control schemes, the actuators are typically the power system stabilizers of synchronous machines. The control action, in this case, can not directly act upon the power-angle relationship of the machines. In this context, the gridforming control for power converters offers the opportunity of an effective wide-area control: grid-forming converters present in fact a direct formulation of the power-angle control law, and therefore the possibility of directly acting upon it. The paper proposes an extension of the grid-forming control, including a specific additional control action based on a remote frequency signal. The proposed concept is proved with a simple representative system, and then demonstrated with two application cases, the standard IEEE 39-bus system and the European power system. The results indicate that the proposed participation of grid-forming converters in the wide-area control leads to a considerable improvement of the dynamic characteristics of the system
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