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This paper presents some aspects on measurements of radiated emission from a Laptop. The used Standards are presented and discussed. The measurements were carried out in a Semi-Anechoic Chamber (SAC) in accordance with EN 55022 (CISPR 22) Standard. The test arrangement was in accordance with IEC 61000-4-3 Standard and the following equipment was included: reception antenna, signal generator and emission...
This paper presents a shielding effectiveness evaluation for some metallic threads materials. The tests were performed using a non-standardized method in a dual transversal electromagnetic cell (DTEM). The materials' shielding characteristics must be properly evaluated in order to choose an appropriate shielding material. The tests were conducted for three different types of material designated for...
The paper deals with the behavior of a medium / low voltage transformer (MV/LV), for a non-sinusoidal consumer placed in the transformer's secondary winding. The analysis is performed using the Discrete Wavelet Transform (DWT). The monitoring is realized with two data acquisition systems, briefly described in the paper. Problems associated to the conducted and radiated emissions are addressed and...
The paper deals with the design of an electric locomotive drive system used in electric railway transportation. The drive system consists of an induction motor and a voltage source inverter. A dedicated induction motor design algorithm is developed, in order to improve the motor efficiency. The design of the induction motor was realized with MathCAD and validated with Matlab Simulink. In the second...
The capabilities related to active filtering of the Stationary Wavelet Transform — SWT were evaluated considering 3 Daubechy wavelet mothers. Firstly a study on errors was performed on synthetic waveforms. The waveforms were obtained from sinusoids polluted by single harmonics with orders from the range 3…40 and magnitudes, respectively phase differences varied in a systematic manner. The differences...
Computational techniques conceived to improve the efficiency of PQ analysis of quasi-stationary signals acquired from the secondary winding of the excitation transformer in a power plant are addressed. Signals of 30 periods (SN) were analyzed. SN were polluted by white Gaussian noise and "arithmetic average" signals (AS) of one period length were computed for 2 reasons: (a) simpler noise...
The paper deals with the behavior of a medium voltage/low voltage transformer (MV/LV), used to power the excitation circuit of a power group. The transformer's load is nonlinear, therefore inducing strong non-sinusoidal regimes in the primary and the secondary windings of the transformer. Non-sinusoidal regimes are due a thyristor rectifier used to power excitation. Two distinct situations are analyzed,...
The paper focuses on the joint analysis (using Wavelet Packet Transform (WPT)/Discrete Wavelet Transform (DWT) and respectively Fast Fourier Transform (FFT)) of voltages and currents acquired from a generator operating in the Power Plant Turceni, Romania, as a major stage in designing the components of an active power filter (APF). When fast methods, providing accurate results are used, fundamental...
The paper studies high order harmonics in distorted regimes with fast variable loads. Our experimental setup uses a three-phase load, built in laboratory by connecting in pairs, in different configurations, several laptops (from different manufacturers) across phases of a three-phase system. Our original dedicated data acquisition system acquired single phase waveforms, each of 5 periods, corresponding...
The paper deals with the immunity for radiated emissions and compliance with international standards for electromagnetic compatibility (EMC) measurements. EMC standards for GTEM Cell, GTEM Cell construction, GTEM model, generation and distribution of electric and magnetic field inside the GTEM Cell, equipment under test (EUT), radiated emission measurement scheme, are presented. Mobile phone immunity...
The paper deals with the single-phase active filtering used for reducing the harmonic level and electromagnetic interference and to get compliance with the power quality standards. The active filtering in case of a single-phase rectifier is based on a single-phase active filter and a complete current control system that uses pulse-width modulation (PWM) techniques. The power quality and the existing...
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