Search results for "33"
showing 10 items of 1917 documents
Distributed Demand-Response Certification using Blockchain Technology
2021
ANALISI DELLE PRESTAZIONI E MIGLIORAMENTO DI MICROMOTORI ELETTRICI E DI MOTORI ELETTRICI A POTENZA FRAZIONARIA
2012
Modeling Alternatives Sustainable-Energy-Policy for the Supply Chain of Wind Power in Brazil.
2020
Renewable energy studies have received high attention in the last few years due the increasing deployment of alternatives such as wind, solar and biomass, as a result of the urgency in reducing fossil fuels consumption. This situation has involved an important challenge for long-term renewables policy and energy system planning. Brazil is the richest country in terms of renewable sources in Latin American. Brazil has energy generation portfolio not much different form the Colombia one, and the understanding of this very important country will contribute to inspire other countries in the region, particularly Colombia. Since 2004 the Brazilian energy policy promotes wind power development aim…
A New Protection Strategy for Electrical Distribution Systems
2010
In this paper, the authors propose a new protection strategy for electrical Medium Voltage distribution networks, based on a distributed intelligence system composed of a central unit and of many local processing units. The distributed intelligence system can precisely identify and locate faults in suitably limited times. Each local processing unit is composed of a data acquisition system and a data analysis system. The first allows the accurate reconstruction of the fundamental using only 1.5 cycles of under fault transient electrical quantities. The second performs suitably precise on-line fault diagnosis based on the data provided by the data acquisition module. The data acquisition algo…
Application to an italian distribution system of a multiobjective optimal Volt/VAR control strategy: improvements and management problems
2007
In this paper, the experiences and results deriving from the application of a multiobjective optimal management strategy to a distribution network supplying an area in province of Palermo, Italy, are presented. The adopted strategy allows, through the interventions on the Under Load Tap Changers (ULTC) of the primary substations and on tie-switches, to reduce power losses and improve the voltage profiles. To solve the optimization problem, an evolutionary approach has been adopted; it employs fuzzy logic for an adequate and simultaneous fulfilment of the different objectives. The application section presents a deep technical and economical analysis of the results attained, applying the opti…
Load modelling influence on voltage stability assessment in distribution systems. Part II: Extension to a complex radial system and applications
2006
The single-line equivalent model is commonly used for voltage stability studies in both distribution and transmission systems. Referring to a single-line system, in the companion paper [1] the authors presented the theoretical aspects of voltage stability related to the load characteristics. In particular, expressions of the stability index for constant power, constant impedance and constant current loads, singularly and in all the possible combinations have been obtained. This index indicates how far the load node is from its voltage collapse point, allowing the maximum load power beyond which voltage collapse takes place to be evaluated. In this paper a simple method to evaluate the param…
Load modelling influence on voltage stability assessment in distribution systems. Part I: Stability index and critical power for a single-line system
2006
The single-line equivalent model is commonly used for voltage stability studies in both distribution and transmission systems. Referring to a single-line system, in the companion paper [1] the authors presented the theoretical aspects of voltage stability related to the load characteristics. In particular, expressions of the stability index for constant power, constant impedance and constant current loads, singularly and in all the possible combinations have been obtained. This index indicates how far the load node is from its voltage collapse point, allowing the maximum load power beyond which voltage collapse takes place to be evaluated. In this paper a simple method to evaluate the param…
An improved method for determining voltage collapse proximity of radial distribution networks
2005
The two-bus equivalent model is commonly used for voltage stability studies in both distribution and transmission systems. The paper presents a simple method to evaluate, for each bus, the parameters which define the equivalent circuit of a radial distribution network. In particular, a straightforward way for determining the Thévenin equivalent impedance behind a load node is proposed, which allows to better identify the maximum loading point beyond which the voltage collapse takes place in the network. Simulation results show that the proposed method is significantly more accurate than other existing methods on evaluating the critical power at a particular node (i.e. the weak node of the n…
Voltage Collapse Proximity Assessment for Radial Distribution Networks
2005
The paper deals with voltage stability assessment in radial distribution networks. The voltage collapse proximity index already utilized in literature for power transmission systems is assumed. Based on the optimal impedance solution of a two-bus equivalent system, this index indicates how far the load nodes of the actual network are from their voltage collapse points, allowing the weak node and its maximum load power beyond which voltage collapse takes place to be identified. The proposed method differs from the other methods on the determination of the parameters which define the two-bus equivalent of the network, allowing to better identify the maximum loading point beyond which the volt…
Grid-forming converters. A critical review of pilot projects and demonstrators
2022
Grid-forming control can be a useful solution for all dynamic issues in weak grids and for providing ancillary services. It represents the new frontier in modern power electronics, responding to the needs of power systems more and more rich in renewables and, for this reason, with lower inertia. Today, the research on grid-forming is mainly oriented to propose new and more effective control schemes and to evaluate their performances with simulation tools, but few works in the literature focus on the results of on-field experimentation. Therefore, this paper aims to provide a comprehensive review of grid-forming pilot projects and demonstrators developed worldwide. The work describes the mai…