Search results for "electromagnetic [coupling]"
showing 10 items of 263 documents
Electric Power Quality Evaluation in the Presence of Electromagnetic Emissions
2013
The measurements for the assessment of the electric power quality are often carried out in hostile electromagnetic environments. The aim of the paper is analyzing if and how both radiated and conducted electromagnetic emissions can disturb the measurement system used to quantify these disturbances. To achieve the target, an experimental approach is proposed, which, by means of a simple and fast test, allows establishing if the real electromagnetic environment, where power quality analysis is performed, can alter the measurements. © 2013 IEEE.
Experimental EMF characterization of a secondary substation
2015
This paper presents the results of the experimental EMC characterization of a new medium/low voltage (MV/LV) secondary substation, which was developed in the framework of the research project "NEW CAB ELARC". It has two MV/LV transformers, with total rated power of 1000 kVA. To perform the experimental characterization, firstly an analysis was performed of the Italian and European standards recommendations. Different approaches were highlighted and the most appropriate procedures were identified for the measurement of the magnetic fields emissions, at power systems frequency (50 Hz) in steady-state conditions. A dedicated test lab was set up for the secondary substation characterization. Th…
On Thermoeconomic Diagnosis of a Fouled Direct Expansion Coil: Effects of Induced Malfunctions on Quantitative Performance of the Diagnostic Technique
2017
Thermoeconomic diagnosis represents a promising technique for the detection of common faults in refrigeration systems, which are responsible of degradation in their energetic performance. Recently, the authors have carried out a sensitivity analysis of the performance of this method to the thermodynamic conditions of inlet air and to the geometry of the direct expansion coil, in case of degradation induced by evaporator fouling. The analysis showed that the method is able to detect this fault, but sometimes its quantitative assessments are not satisfactory. In order to understand more in-depth the origin of such results and identify margins for refinement of the technique, this paper is aim…
Fast procedure for the calculation of maximum slot filling factors in electrical machines
2017
This paper presents an algorithm for the calculation of maximum slot filling factor in electrical machines. The determination of whole wire cross section that occupy the area of a stator slot is very important in order to estimate the copper losses: The greater is the filling factor the lower are copper losses. The main goal of this paper is to define a simple algorithm for the determination of slot filling factors suitable for all type of slot profiles. The algorithm can be considered as an additional useful tool for the fast design of electrical machine windings.
Oil filled MV/LV Power Transformer Behavior in Narrow Band Power Line Communication Systems
2012
The aim of this paper is to characterize oil-filled power transformers in the narrow-band power-line communication (PLC) frequency range of 50-150 kHz. A new model is proposed for such type of a transformer, in the aforementioned frequency range of interest, in order to study its influence on the signal transmission and to investigate the possibility that the PLC signal can cross the power transformer itself. The new model is simpler than those previously proposed in literature, and it can be used in the whole frequency range available for NB PLC according to the CENELEC EN 50065-1 A-band. In order to validate the model, simulation and measurement results are compared for four oil-filled po…
Numerical studies of the melting process in the induction furnace with cold crucible
2008
PurposeAims to present recent activities in numerical modeling of cold crucible melting process.Design/methodology/approach3D numerical analysis was used for electromagnetic problem and 3D large eddy simulation (LES) method was applied for fluid flow modeling.FindingsThe comparative modeling shows, that higher H/D ratio of the melt is more efficient when total power consumption is considered, but this advantage is held back by higher heat losses through the crucible walls. Also, calculations reveal that lower frequencies, which are energetically less effective, provide better mixing of the melt.Originality/value3D electromagnetic model, which allows to take into account non‐symmetrical dist…
Characterization of electromagnetic noise suppression sheet for aerospace applications
2016
Electromagnetic noise suppression sheets based on absorber materials can be an interesting solution to reduce or suppress noise emissions at a high-frequency region that may cause complex EMI problems. These materials usually are characterized by their permeability but their performance also depend on other factors such as dimension, geometry, thickness or noise source kind. Three experimental methods are proposed in order to characterize absorber sheets in different kind of applications taking into account the last factors. These setups make it possible to test several samples with different characteristics and to analyse the absorption capacity in applications with transmission line probl…
A Flux and Speed Observer for Sensorless SPIM Applications
2010
It is usual to find single-phase induction motor (SPIM) in several house, office, shopping, farm, and industry appliances, which is become more sophisticated and requires the development of high performance alternatives to drive a SPIM. All proposed strategies to improve the performance SPIM need the evaluation of the rotational speed or position information. Since the use of conventional sensors to measure the rotational speed cannot be justified for SPIM applications, the adoption of a sensorless strategy is a more reasonable option for these cases. This paper presents a flux and speed observer for sensorless applications involving SPIMs. The performance of the proposed observer is verifi…
Optical Fibre Control-Measurement Systems Of Compound HV/HP Electrical Equipment
1988
Responsible electrical equipment should be controlled during the work in care of their high reliability. Traditional control measurement systems cannot fulfil the task because of the hard conditions in which the equipment may operate (various electrical potentials, electromagnetic interferences, changes of temperature, etc.). The development of fibre optic transmission media and fibre optic sensors allows the construction of new control measurement systems for cooperation with such electrical equipment as: converters, generators, treLnsforniens, switch bays, busbards, etc. Those optical fibre structures, composed of bu-ses and sensors are subject of this paper. The main attention is paid to…
A portable instrument for the location and identification of defects generating PD
2011
A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…