Search results for "ELECTRICITY"
showing 10 items of 1225 documents
Novel test bed for induction heating power supplies
2006
Power supplies used in induction heating industrial applications must be entirely tested after its manufacturing in order to assure its security and reliability by means of a full power running test of several hours of duration. Nowadays this test is done with a dissipative load which implies a large waste of energy. This paper proposes a new high efficiency test system for induction heating generators. It incorporates a regenerative electronic load which allows an extraordinary improvement of the efficiency of this test with an important economical and ecological benefit.
A boundary element model for structural health monitoring using piezoelectric transducers
2013
In this paper, for the first time, the boundary element method (BEM) is used for modelling smart structures instrumented with piezoelectric actuators and sensors. The host structure and its cracks are formulated with the 3D dual boundary element method (DBEM), and the modelling of the piezoelectric transducers implements a 3D semi-analytical finite element approach. The elastodynamic analysis of the structure is performed in the Laplace domain and the time history is obtained by inverse Laplace transform. The sensor signals obtained from BEM simulations show excellent agreement with those from finite element modelling simulations and experiments. This work provides an alternative methodolog…
Six-years-long effects of the Italian policies for photovoltaics on the grid parity of grid-connected photovoltaic systems installed in urban contexts
2017
Abstract The purpose of this study is investigating the grid parity (GP) time and the levelized cost of energy (LCOE) of grid-connected photovoltaic (PV) systems installed in densely urbanized contexts. The analysis, which was elaborated for three Italian cities, considered the effects of the promoting policies enacted by the Italian government from June 2010 to May 2016. An appropriate methodology was applied with the aim of realistically defining the energy produced by PV systems installed on buildings with different roof types and number of floors. The calculus of the disbursements considered the operating, maintenance and insurance costs and the wear of PV panels and inverters. The resu…
Planning Rehabilitation Actions on Water Distribution Networks in Condition of Data Scarcity
2011
The paper shows a viable approach to the selection of water networks rehabilitation actions, in condition of data scarcity and uncertainty, based on the use of four concise performance literature indices, allowing the analysis and identification of efficient, reliable and robust rehabilitation alternatives, even if assessed on the basis of a relatively small amount of data. A promising statistical sampling method of water consumptions is also described, that may be fruitfully employed within the proposed approach for drafting water balances at network district scale in order to quantify the extent of leakages. The illustrated case study shows that the selected indices are capable to describ…
Short-term prediction of household electricity consumption: assessing weather sensitivity in a Mediterranean area
2008
Abstract Urban microclimatic variations, along with a rapid reduction of unit cost of air-conditioning (AC) equipments, can be addressed as some of the main causes of the raising residential energy demand in the more developed countries. This paper presents a forecasting model based on an Elman artificial neural network (ANN) for the short-time prediction of the household electricity consumption related to a suburban area. Due to the lack of information about the real penetration of electric appliances in the investigated area and their utilization profiles it was not possible to implement a statistical model to define the weather and climate sensitivities of appliance energy consumption. F…
Design optimization for the adoption of bonded magnets in PM BLDC motors
2014
The increment of the manageable power in machines where the normally adopted ferrites are replaced with bonded magnets can vary and can introduce saturation problems depending on the variations in the magnetic circuit design. The saturation of the magnetic circuit distorts the phase voltages, introducing undesired harmonics in the connection to the mains. Combined modifications of both stator poles and rotor ring of a Brushless DC motor are proposed to evaluate their impact on the increment of the manageable power and on the harmonic content. Several magnetic circuit modifications have been considered and the paper presents the results of the most reasonable solutions, obtaining significant…
Economic evaluation of PV system for EV charging stations: Comparison between matching maximum orientation and storage system employment
2016
This article addresses the problem of the choice of a generation system to be implemented to reduce the impact of charging electric vehicles at University. Based on the behaviour of the student population, it is identified the electrical load. Two possible solutions are evaluated in order to manage the peak load: an orientation of the panels in order to increase the power at defined time and the use of storage system. The main strength and weakness points of two systems are investigated by taking into account the Levelized Cost of Energy.
Multi-step ahead electricity price forecasting using a hybrid model based on two-layer decomposition technique and BP neural network optimized by fir…
2017
In the deregulated competitive electricity market, the price which reflects the relationship between electricity supply and demand is one of the most important elements, making it crucial for all market participants to precisely forecast the electricity price. However, electricity price series usually has complex features such as non-linearity, non-stationarity and volatility, which makes the price forecasting turn out to be very difficult. In order to improve the accuracy of electricity price forecasting, this paper first proposes a two-layer decomposition technique and then develops a hybrid model based on fast ensemble empirical mode decomposition (FEEMD), variational mode decomposition …
Robust Multi-Objective Optimal dispatch of Distributed Energy Resources in Micro-Grids
2011
Modern distribution systems are implemented through micro grids: small power networks where generation is close to consumption and ICT supports the coordinated management of the different energy resources. In such systems, the central control unit manages energy dispatch from the different sources according to different criteria (technical, economical and environmental) and takes care of tertiary regulation. Such optimization for the tertiary regulation is performed with a time interval that typically is of 24 hours. This is due to the fact that it is necessary to take into account the charge and discharge cycles of storage systems. On the other hand, such long time leads to large errors in…
Photovoltaic plant array reconfiguration: Design of a new device
2014
An efficient strategy to improve unequally irradiated PV plants performances is based on the reconfiguration of the connections between the modules. In this paper, an algorithm, for this purpose conceived, is presented. Moreover, the design, realization and finally also the set up of a new reconfiguration system device is fully shown and discussed. The algorithm conceived simulates several possible series-parallel connections under varying irradiation conditions, and determines the optimal modules connection in order to get the maximum output power. In this way, the reconfiguration system may set up the reconfiguration strategy. The reconfiguration system prototype set up, basically consist…