648 research outputs found
Risk-Based Security and Control Framework for Power System Operation Under Significant Amounts of HVDC-connected Wind Power Generation
No full textIn the context of power system operation, probabilistic techniques can provide a deeper insight into security aspects compared to deterministic approaches, by quantitatively considering power system uncertainties and contingency impact. Moreover, they can be helpful to identify and suggest operators the most adequate control actions to reduce the operational risk. This paper proposes an original framework for risk-based assessment and control of operational security in High-Voltage Alternating Current (HVAC) power systems connected to Multi-Terminal High-Voltage Direct Current (MTDC) networks like those envisaged for the integration of future, large off-shore wind farms. After the presentation of a security assessment methodology based on the concept of risk, the paper investigates three possible preventive control strategies to reduce the risk of high current by exploiting control resources available in the system (specifically, generating units and power injections from MTDC grids). Results of the methodology applied to a test system and to a realistic power system (adapted from the Italian transmission network) are presented and discussed
Stochastic modelling of aggregated thermal loads for impact analysis of demand side frequency regulation in the case of Sardinia in 2020
No full textThis paper proposes a model of the thermal dynamics and of the end-use of amics and of the end-use of domestic refrigerators (fridges) and water heaters (boilers) in the foretasted scenario of the Sardinian electric network in 2020. This model is employed to evaluate the potential variations of power demand of the aggregates of fridges and boilers during one year in the considered scenario. The resulting quantities can be considered as a form of power reserves to be used for contributing to the frequency regulation through a proper demand side response strategy. The particular case of the system for frequency control proposed by the European Network of Transmission System Operators for Electricity (ENTSO-E) is then analysed by simulations in order to show advantages and drawbacks
Linguaggio Naturale Controllato per la specifica di sistemi di automazione: definizione
No full textRapporto CESI SPES/RET12 - 00
Probabilistic risk-based security assessment of power systems considering incumbent threats and uncertainties
No full textIn-depth security analyses of power systems (PSs) require to consider the vulnerabilities to natural and human-related threats, which may cause multiple dependent contingencies. On the other hand, such events often lead to high impact on the system, so that decision-making aimed to enhance security may become difficult. Introducing the uncertainty, the risk associated to each contingency can be evaluated, thus allowing to perform effective contingency ranking. This paper describes an in-depth security assessment methodology, based on an ``extended'' definition of risk (including threats, vulnerability, contingency, and impact) aimed to perform the risk assessment of the integrated power and Information and Communication Technology (ICT) systems. The results of the application to test cases and realistic PSs show the added value of the proposed approach with respect to conventional security analyses in dealing with uncertainty of threats, vulnerabilities, and system response
Risk-Based Dynamic Security Assessment for Power System Operation and Operational Planning
No full textAssessment of dynamic stability in a modern power system (PS) is becoming a stringent requirement both in operational planning and in on-line operation, due to the increasingly complex dynamics of a PS. Further, growing uncertainties in forecast state and in the response to disturbances suggests the adoption of risk-based approaches in Dynamic Security Assessment (DSA). The present paper describes a probabilistic risk-based DSA, which provides instability risk indicators by combining an innovative probabilistic hazard/vulnerability analysis with the assessment of contingency impacts via time domain simulation. The tool implementing the method can be applied to both current and forecast PS states, the latter characterized in terms of renewable and load forecast uncertainties, providing valuable results for operation and operational planning contexts. Some results from a real PS model are discussed
Il profilo filosofico e culturale di un metafisico neoclassico. A proposito di "Il filosofo e la fede. Il cristianesimo ‘moderno’ di Gustavo Bontadini" di Leonardo Messinese
No full textThis paper examines Leonardo Messinese’s volume, Il filosofo e la fede. Il cristianesimo ‘moderno’ di Gustavo Bon-tadini. From the book emerges a philosophical portrait of the Milanese thinker useful to understand the fun-damental points of his theoretical proposal: neoclassical metaphysics, brought out by the Author in relation to the dispute with Emanuele Severino. Some lesser-known cultural, civil and political aspects of Bontadini’s intellectual biography are also exposed. The intent of the volume is to spread a greater knowledge of the fig-ure of Bontadini within Italian philosophical culture, particularly that of Catholic inspiration
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