1,721,059 research outputs found
Variability of track to ground conductance measurement
No full textA previous work, published in ACTA IMEKO journal, pointed out the attention about probable variability performing track to ground conductance measurements, using the method indicated in the A.3 of the IEC 62128-2 international standard. In this work the presence of such measurement variability has been proven by on site measurements
The variability of microstrips formulas as a source of uncertainty in microwave setups
No full textAbstract Microstrips are used quite often to connect microwave measuring equipment to PCB mounted devices and represent a relevant element of the whole test setup. Their characteristics (the most relevant the characteristic impedance) may be determined by design or later experimentally; in any case they represent a relevant source of uncertainty that must be accounted for. This work reports in full, verifies and compares formulations appearing in the literature of the last 50 years; the study is carried out by sensitivity analysis (for the most relevant geometrical parameters and the dielectric permittivity of the substrate) and by comparison with experimental results
Integrated electromechanical simulation of traction systems: Relevant factors for the analysis and estimation of energy efficiency
No full textElectromechanical analysis and simulation of traction systems are required to estimate the power consumption, to size the power system and to optimize system parameters for energy saving. The number of variables and parameters (mechanical and electrical) is huge, affected by various degrees of uncertainty. An integrated simulation approach is presented, where the requisites for the correct evaluation of regenerative capability are considered. © 2012 IEEE
Discussion of Electrical and Electromagnetic Impact on Environment and Users of Electrified Transports
No full textModern transportation systems are integrated in the urban fabric and next to populated centers. For this reason the assessment of the impact in terms of electrical and electromagnetic emissions is quite relevant: stray current, touch voltage, human exposure and interference to implantable devices. Standards, regulations and reference scenarios are quite articulated and should be comprehensively and accurately addressed in the contractual specifications and at the preliminary design stage of transportation projects. To this aim this work considers relevant standards, typical phenomena and system assurance elements to define comprehensively and unambiguously the most important interfaces, avoiding the typical pitfalls of generic statements and common misunderstandings
Resistance and internal inductance of traction rails at power frequency: a survey
No full textThe electrical behavior of traction rails is considered. The values of resistance and internal inductance resulting from 80 years of literature are evaluated and compared; average values (with confidence intervals) are derived as a reference for further developments. The values are the results of direct measurements and information from practice and convention, so attention is given to measuring methods and to any simplifying assumption. The statistical properties of the published experimental results are evaluated as well as the correspondence with theoretical results
Variability and consistency of Feature Selective Validation (FSV) method implementation
No full textThe feature selective validation method is a recognized validation tool that assesses the similarity between datasets especially for electromagnetic measurements and models; its use may be extended to many problems and applications involving electric systems. Implementation flaws and ambiguities are identified that may impair its accuracy and reliability; they are considered by evaluating the uncertainty and sensitivity of the output for some reference datasets that are available for downloading
Robust estimates for validation performance indexes of electric network models
No full textThe validation of an electric traction network simulator is addressed by selecting the testing conditions and considering three performance indexes, which evaluate both simply amplitude and other curve features. A common interpretation scale is proposed to verify the agreement between them. Moreover, since the most complex cannot be fully used without a graphical representation of its output, this is simplified, in order to conclude the validation with an estimate of accuracy that is as close as possible to the classical declaration that accompanies measuring instrument
Statistical distributions of validation performance indexes for experimental data uncertainty
No full textThe behavior of a set of performance indexes used for model validation is considered and analyzed with Monte Carlo simulations and determination of distributions of output quantities and their statistical estimates. A relevant result regards an offset appearing at index output, when considering input data uncertainty, for cases of good correspondence between model and experimental results and consequently very low index values near zero. Such offset represents a systematic error of indexes considered as measuring tools. Additionally, index output is also characterized in terms of dispersion
Distribution of stray current based on 3-Dimensional earth model
No full textAn accurate electric model of the earth is important for many applications related to electric traction and distribution systems like the stray current. As the DC electrified traction system is the potential source of the stray current, the operation of traction vehicles such as trains and trams makes the emergence of stray currents in the area of rails and under the rails. These leakage currents can adversely affect pipelines or cable lines near the rail [7][11]. There exist numerous models which have been modeled this phenomena [2][4][11], all models are based on one Dimensional earth structure, actually the nature of the earth underneath of the railways could not be represented as a homogeneous medium. The characteristics of the soil vary depending on the location and locally with depth, and a homogeneous earth model might be inadequate. [1] shows that even the multi-layered earth models are not reliable to be the base of the calculation of several applications related to the earth and grounding systems and it is required an accurate earth model which can give a better overview of whole structure of the underneath ground. In this work after a general presentation of the existing and proposed earth model, it is presented a comparison between the calculation of the stray current propagation based on one and 3-Dimensional earth model
Experimental investigation on radiated emissions generated by pantograph arcing and their effects on telecommunication bands
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