Search results for "Volt"
showing 10 items of 2187 documents
An harmonic test condition for the metrological characterization and the operating principle identification of reactive static meters
2008
This paper faces the problem of the metrological characterization of the static meters for reactive energy in the presence of harmonic distortion. Starting from the only available accuracy test condition in the presence of harmonics introduced in the Standards for active static meters, an experimental approach is proposed for the verification of such meters in the presence of harmonic distortion, as well as for the individuation of their operating principle. A theoretical validation of the obtained results is presented by means of a comparison with a standard and a commercial static meter with a known operating principle.
Static meters for the reactive energy in the presence of harmonics: an experimental metrological characterization
2009
Electricity metering plays a crucial role for all the commercial transactions on the energy market. Thus, an accurate evaluation of the performance of the electricity metering equipment is required not only in the reference operating conditions but also in the presence of disturbances affecting the power systems. As regards this matter, this paper analyzes the main aspects related to the metrological characterization of the static meters for the reactive energy in the presence of harmonic distortion. Attention is focused not only to the meters covered by the current standards but also to the meters of better accuracy and to the reference standard meters. The analysis is supported by several…
Influence of MV distribution networks structure on voltage dips propagation
2003
In this paper, transient behaviour due to voltage dips which occur in electric power MV distribution networks as a consequence of a fault by using an improved ATP circuit-breaker model are reported. The circuit-breaker is simulated by using a tool written in MODELS language and by arranging a time-variable differential arc-conductance based on the combination of Mayr's and Cassie's equations. An accurate analysis of the transient subsequent to circuit-breaker operation, in different fault conditions, are reported in order to show how the amplitude of the dip depends on the fault type, location and network structure.
Control of an open-end winding induction machine via a two-output indirect matrix converter
2014
In this paper an Indirect Matrix Converter (IMC) with two output stages feeding an open-end winding induction machine is presented. The IMC has the advantage of having nobulky energy storage elements and with the two output stages up to 1.5 times the input phase voltage can be obtained across the windings of the machine, without overmodulation. A vector control scheme for the machine currents is used along with a modulation strategy for the converter two-output stages to reduce the common mode voltage and compensate the phase zero sequence currents. Simulation results showing the performance of the controlscheme and the reduction of zero sequence and common mode voltages are presented and d…
A PC-based wattmeter for accurate measurements in sinusoidal and distorted conditions: Setup and experimental characterization
2012
This paper presents the development of a high-accuracy sampling wattmeter, which can be employed with both sinusoidal and distorted input signals. The proposed personal computer (PC)-based system is a simple, portable, and low-cost solution because it is based on two commercial data acquisition boards connected to a common PC. Owing to this solution, the voltage is sensed directly, avoiding expensive voltage dividers, while the current is sensed by means of a noninductive current shunt. Commercial software is also used for data processing and implementation of the virtual instrument. The setup of the PC-based wattmeter is described, with a detailed description of the correction strategy of …
New Architectural Models and Building Tradition: A Dialogue in Early Modern Sardinia - The Jesuit Church in Sassari
2014
L'architettura nella Sardegna di età moderna è caratterizzata da una forte continuità con pratiche antecedenti. Nella seconda metà del XVI secolo, nuovi modelli, legati in particolare alle nuove tendenze nel campo dell'architettura militare e il classicismo della controriforma cattolica, affiancano la tradizione costruttiva gotica.La chiesa dei Gesuiti di Sassari offre un interessante esempio di intreccio tra queste modalità architettoniche, causato da un improvviso cambio alla guida del cantiere. Giovan Maria Bernardoni, un architetto gesuita italiano, redasse il progetto iniziale della chiesa sul modello del Gesù di Roma, ed essa fu parzialmente costruita sotto la sua direzione. Dopo la s…
Feasibility analysis of a renewable hybrid energy system with producer gas generator fulfilling remote household electricity demand in Southern Norway
2016
Abstract Hybrid energy system is increasingly emerging as an option to produce energy for the remote areas. This paper presented an economic feasibility analysis of a single standalone house operating with a hybrid power plant consisting of a fixed capacity producer gas generator (2 kWe) and other renewable energy sources (Photovoltaic and wind). The National Renewable Energy Laboratory's Hybrid Optimization Model for Electric Renewable (HOMER) was employed which evaluated techno-economic analysis based on the criteria of net present cost and levelized cost of electricity. Taking the site specific daily average solar radiation, average wind speed and load data into account, renewable hybrid…
Design, fabrication, and analysis of a spin-valve based current sensor
2004
Abstract In this work, we suggest a novel current sensor design, based on spin valve technology, with a full Wheatstone bridge configuration. The principal characteristic is that the four magnetoresistance sensing elements, fully active, are deposited and patterned at the same time. This way, differences among them should be insignificant, so improving voltage offset and drift temperature parameters. The complete IC fabrication process involves only three lithography steps, making the process cheaper and faster. In order to get a balanced bridge, the measured current must be properly driven, by means of an auxiliary PCB. Some prototypes, with different input impedances, have been fabricated…
Techno-economic sizing of off-grid hybrid renewable energy system for rural electrification in Sri Lanka
2015
Abstract Off-grid hybrid renewable-energy-based power systems for rural electrification have become an attractive solution for areas where grid electricity is not feasible. Hybrid energy systems use several energy technologies, and the selection of proper technologies with optimum sizing of the selected components has become very important. The objective of this study has been to investigate the optimum configuration of a hybrid system that can supply electricity to a rural community in Sri Lanka. A rural village in Siyambalanduwa (Sri Lanka) comprising approximately 150 households with a resultant daily electricity demand of 270 kWh and a nighttime peak of 25 kW has been studied. This regi…
Wind Electrical energy generating systems EMC. A dedicated experimental simulator for tests
2008
In wind electrical energy generating systems, due to fast voltage and current fluctuations, the power converter represents a source of electromagnetic disturbances. EMI problems of stand alone wind generators are here analysed in order to take into account many different power quality problems which result in voltage fluctuations and harmonics in the net. This paper, moreover, presents a wind turbine experimental simulator (WTES) that moves a wind electrical energy generating system (WEEGS) to carry out EMI measurements and the relative experimental results. The WEEGS here taken into account comprises a wound rotor induction generator (WRIG) in which the frequency transformation from the ro…