Search results for " sistemi"
showing 10 items of 1888 documents
On the de-energization of over-head low-voltage lines under high-impedance fault conditions
2018
Downed distribution conductors in overhead distribution systems, may not be a concern for equipment, but greatly challenge the safety of persons, as well as the integrity of properties. Upstream overcurrent protective devices may not be able to detect the magnitudes of fault currents resulting from these high-impedance faults. Even though protective devices capable to detect such faults have been available on the market, not all the utilities have equipped their stations with these products, likely due to the costs. In this paper, the authors formalize the problem, and propose a possible cost-effective solution for the low-voltage over-head lines with neutral wire. Such solution includes a …
Economical Incentives and Systems of Certification for the Production of Electrical Energy from Renewable Energy Resources
2007
In order to succeed in observing the international agreements undertaken in the Kyoto agreement protocol, today it is necessary to increase the electrical energy production from renewables energy resources (RERs). In this paper a complete description of the Italian incentive systems for the production of electrical energy from photovoltaic (PV) and other RERs is done. Moreover, some considerations about the effects of the incentive actions on the wide spread of RERs to produce electrical energy are reported; particular attention is paid in the economical analysis related to PY and wind systems.
A simple operation strategy of battery storage systems under dynamic electricity pricing: An Italian case study for a medium-scale public facility
2014
In the electricity market, wholesale energy prices depend on the balance between energy production and load demand. In the last few years, electricity market has become more and more flexible as many utilities have started to replace the fixed retail prices schemes with prices changing during the day. Dynamic pricing, also known as Real-Time Pricing (RTP), reflects the trend of the wholesale market and allows to reduce the volatility of the wholesale prices, also contributing to a reduction of demand peaks. Electricity customers take advantage of dynamic pricing by shifting their consumption according to the real-time prices or by using Battery Energy Storage Systems (BESS) to shift electri…
Economic feasibility of a customer-side energy storage in the Italian electricity market
2015
Electricity prices show significant short-term variations during the day due to the need of balancing supply and demand in real time. Normally, customers are not exposed to these variations but pay a constant electricity price. In an attempt to reduce the volatility of the wholesale prices, several utilities are moving from conventional fixed-rate pricing schemes to new market-based models, where the electricity price can fluctuate during the day depending on the market conditions. Examples of time-dependent pricing schemes are Time-Of-Use (TOU) tariffs, where the electricity price can take two or three price levels during the day, or Real-Time Pricing (RTP) tariffs, where the energy price …
Impact of non-programmable renewable sources in Day-Ahead Market in Sicily. Reasons to make more flexible and smarter the national transmission grid.
2014
This article describes technical and market aspects that characterize the Sicilian electrical system, the non-programmable renewable sources impacts on the energy markets (Day-Ahead Market and ancillary services market) and on Sicilian system operation, to evaluate the grid integration of renewable energy sources in a future Sicilian smart grid.
Sustainable integration of Renewable Energy Systems in a Mediterranean island: a case study
2013
Starting from a previous technical and economical feasi-bility study, this paper analyzes the integration of Renewable Energy Sources into an existing territory with specified features of the natu-ral landscape and of the built environment. The work puts into evi-dence that territories development must use suitable tools and rules based on integrated knowledge, since technical feasibility studies do not assess the sustainability of the proposed infrastructures within the built environment and landscape. The studied system is in the is-land of Pantelleria situated between Sicily and northern Africa.
The Relevance Of The Preform Design In Coining Processes Of Cupronickel Alloy
2007
Coining is a forging process in which a metallic disk, characterized by a low volume‐surface ratio, is deformed with the aim to impress 3D images on its three surfaces. Due to the large production volumes and, at the same time, to the high quality standards required to the final products in terms of final dimensions, tolerances and surface finishing, such closed‐die, cold forging process requires a careful evaluation and choice of the proper operative parameters. In particular, along with technological parameters as the die velocity, die stroke and lubrication, which, in turn, contribute to affect the pressure values on the die surfaces, and thus the press choice, geometrical parameters as …
Economic Robustness Analysis of Adaptive Chart Schemes for Monitoring the Total Nonconformities Number in Inspection Units
2015
In recent years, a variety of enhanced schemes for the c chart have been developed aimed at the effectiveness improving of the related statistical process control (SPC) procedures. However, the performance of such chart schemes can be very sensitive to values assumed for some operating and cost parameters, in particular to the considered process shift magnitude arising from out-of-control conditions. In such a circumstance, the effectiveness of such chart schemes can be subjected to substantial reductions when they are implemented in operative contexts given that, in practice, such value is unknown and it can be very difficult to accurately estimate. For this reason, in the present paper i…
Cambiamenti climatici, selvicoltura e popolamenti a rischio
2014
Il contributo prende in esame alcune criticità dei popolamenti al margine dell'areale di diffusione, in quanto soggetti a pressioni ecologiche a seguito del cambiamento climatico in atto. Si esaminano casi di studio e si indicano alcuni indirizzi colturali volti a ridurre gli stress e le criticità in atto
Il governo del capitale intellettuale attraverso il raccordo tra modelli contabili e di System Dynamics. Una prospettiva di programmazione e controll…
2004
Il presente scritto tenta di far luce sul tema del capitale intellettuale in una prospettiva economico-aziendale, focalizzando in particolare il concetto di governo della conoscenza aziendale. La tesi sostenuta dagli autori è che i processi inerziali di sviluppo e declino della conoscenza non devono essere astrattamente ignorati, relegando l’area Organizzazione e Sistemi al rango di centro di spesa discrezionale. Questa semplicistica prospettiva di analisi può indurre il management all’adozione di politiche miopi, che portino cioè a rinviare investimenti necessari in sviluppo della conoscenza, con l’unico obiettivo di non deprimere i risultati reddituali di breve andare. A tal riguardo, si …