Génie électrique
Method for diagnosis of the effect of AC on the X70 pipeline due to an inductive coupling caused by HVPL
The inductive coupling between high-voltage power lines (HVPL) and buried pipelines has been an important research subject over the last decades. This coupling may result in alternating current (AC) on pipelines that may pose a serious threat to the pipelines due to corrosive effects and the cathodic protection (CP) performance. A method to investigate the effects of the induced AC density on the corrosion and the CP performances of the X70 steel buried pipeline due to the inductive interference caused by HVPL is proposed in this study. The method is based on the corrosion parameters of the X70 steel pipeline obtained by electrochemical measurements such as Tafel slopes, corrosion current densities, and corrosion potentials. These parameters were used as boundary conditions in the elaborated CP model. The results showed that, firstly, the induced AC density affects the electrochemical characteristic of the X70 steel and accelerates the corrosion of the pipeline. On the other hand, the impressed current cathodic protection is incapable of maintaining the CP potential level. However, some technical solutions were proposed to prevent the pipelines from AC corrosion and maintain the CP potential to an acceptable level. Voir les détails
Mots clés : electrochemical analysis, interference, chemical variables measurement, power cables, steel, electric current measurement, Corrosion protection, pipelines
Pipelines Corrosion Due to the Electromagnetic Pollutioncaused by the High Voltage Power Lines
This paper studies the effect of theelectromagnetic pollution caused by the high voltage powerlines on the corrosion of the buried pipeline. In this objective,the finite element method (FEM) was used to calculate themagnetic field distribution and the induced current densitiesin the buried pipeline caused by both horizontal and verticalconfiguration of the HVPL during steady state conditions. Inorder to diagnose the effect of the electromagnetic pollutionon the corrosion of the pipeline, the electrochemicalimpedance spectroscopy (EIS)measurements were used tocharacterize the corrosion polarization properties of X70 steelin simulated soil at various AC current densities. The resultsshow that, the electromagnetic pollution caused by the highvoltage power lines affect the electrochemical characteristicsof the X70 steel pipeline and accelerate the corrosion of thepipeline. Voir les détails
Mots clés : Electromagnetic pollution, high voltage power line, induced current density, X70 steel pipeline, corrosion, Finite Element Method, Electrochemical impedance spectroscopy
Maximum Power Point Tracking of Wind Energy Conversion System Using Multi-objective grey wolf optimization of Fuzzy-Sliding Mode Controller
Ongoing electricity demand and the increasing growth of population have become necessary to provide alternative and clean sources of energy. Wind energy is one of the most important sustainable energies but the irregular characters of the primary source, which is characterized by a random wind speed variation, makes the process of control is difficult in order to maximize the power. This paper presents a multi objective grey wolf optimization (MOGWO) of fuzzy sliding mode controller in order to maximize the power captured by wind turbine; meanwhile, the mechanical loads are alleviated for variable speed wind energy conversion system (VS-WECS); firstly, Fuzzy logic theory based sliding mode control is developed by collecting the sliding surface data to reduce the chattering effect caused by the SMC, then the Grey Wolf Optimization is introduced to solve multi-objectives functions of WECS which are extracting the maximum power and alleviation the mechanical loads in order to find the optimal parameters of Fuzzy-Sliding mode controller to drive the conversion system to the optimal operating point. The obtained results are compared with those given by Sliding mode controller and Fuzzy-Sliding mode controller in which our proposed method can ensure a better dynamic behavior of the WECS. Voir les détails
Mots clés : Wind Energy Conversion System WECS, Maximum Power Point Tracking MPTT, Sliding mode control, fuzzy logic control, MO-GWO
Fuzzy-PSO controller design for maximum power point tracking in photovoltaic system
Photovoltaic power generation system becomes increasingly important, highly attractive as a clean and renewable energy sources, widely used today in many applications. Recently, researchers have strongly promoted the use of solar energy as a viable source of energy due to its advantages and which it can be integrated into local and regional power supplies. The P–V curve of photovoltaic system exhibits multiple peaks under various conditions of functioning and changes in meteorological conditions which reduces the effectiveness of conventional maximum power point tracking (MPPT) methods and the Particle swarm optimization (PSO) algorithm is considered to be highly efficient for the solution of complicated problems.In this paper, the application of this approach based MPPT algorithm for Photovoltaic power generation system operating under variable conditions is proposed to optimize and to design an intelligent controller comparing to conventional one. PSO Approaches is considered to select and generate an optimal duty cycle which varies with photovoltaic parameters in order to extract the maximum Power. Simulation results show that the proposed approach can track the maximum power point faster and can improve the performance of the system compared to the conventional method. Voir les détails
Mots clés : Particle Swarm Optimization (PSO), photovoltaic System, Boost, PWM, MPPT, FLC
Particle Swarm Optimization Backstepping Controller for a Grid-Connected PV/Wind Hybrid System.
The current paper investigates Backstepping controller using Particle Swarm Optimization for Photovoltaic "PV"/Wind hybrid system. The tested system was connected to the grid by three-phase inverter commissioned to address current depending on the grid parameters and still deliver its reactive power to zero. Backstepping control is a recursive methodology that uses Lyapunov function which can ensure the system stability. The best selection of Lyapunov function gains values should give a good result. In most of the literatures, the choice was based on the expertise of the studied system using hurwitzienne method considered as heuristic choice. The aim of this work is to propose an optimization using a powerful method commonly called Particle Swarm Optimization "PSO" able to calculate the gains values depending on the grid parameters by minimizing a selected criterion. The simulation results show that the PSO Backstepping controller gives good results shown in the current injected to grid with a small harmonic distortion despite climate change in the wind speed and the irradiation, which also shows the robustness of the applied control. Voir les détails
Mots clés : PV/Wind Grid-Connected, MPPT, Backstepping Controller, PSO, Matlab/Simulink
Contribution au Diagnostic des Défauts dans les MachinesTournantes par Analyse Multirésolution
La fonction principale de la surveillance vibratoire des machines tournantes est de fournirdes connaissances sur l’état de fonctionnement réel de la machine à chaque moment sansarrêter la ligne de production. Ceci permet d’éviter les pertes de production et améliore lafiabilité et la sécurité.La transformée en ondelettes (TO) est l’une des techniques les plus importantes detraitement du signal vibratoire qui peut être utilisé pour détecter et diagnostiquer les défautsdes machines tournantes. Néanmoins, les limites de cette technique sont les suivants: Il fautune présélection de l’ondelette mère convenable et le niveau approprié de décomposition quicontient les informations nécessaires pour le diagnostic des défauts .Afin de résoudre cesproblèmes, une nouvelle approche de diagnostic de défauts de roulements sera développéedans ce travail. Cette nouvelle méthode a l’avantage de ne pas souffrir des limitations destechniques de diagnostic usuelles. Voir les détails
Mots clés : analyse vibratoire, diagnostiquer les défauts de roulement, Transformée de Fourier Rapide, Analyse temporelle, l'analyse de Cepstre, l'analyse de l'enveloppe, transformées en ondelettes
Eddy Current Analysis of Titanium submitted to the stress
Inspection by eddy current is one of techniquesthat are very used in nondestructive evaluation of materials. Theobject of this work is to carry out an analysis of the residualstresses in the material created by external solicitations andanalyses by eddy currents as a non destructive testing method.The analysis of the eddy current results will be compared to theresults obtained by the traditional methods (X-rays diffraction…)in order to determine a relation between the non-destructive testsand destructive. It was shown in this work that all microstructuremodifications of the samples were detected and they can bequantified by eddy current impedance measurement. Theimpedance analysis by eddy current will be correlated with themicrostructure changes observed in the material because ofplastic damage and fatigue. Voir les détails
Mots clés : NDT, Stress, Eddy Current, impedance, titanium
Pipelines Corrosion Due to the Electromagnetic Pollution caused by the High Voltage Power
This paper studies the effect of the electromagnetic pollution caused by the high voltage power lines on the corrosion of the buried pipeline. In this objective, the finite element method (FEM) was used to calculate the magnetic field distribution and the induced current densities in the buried pipeline caused by both horizontal and vertical configuration of the HVPL during steady state conditions. In order to diagnose the effect of the electromagnetic pollution on the corrosion of the pipeline, the electrochemical impedance spectroscopy (EIS) measurements were used to characterize the corrosion polarization properties of X70 steel in simulated soil at various AC current densities. The results show that, the electromagnetic pollution caused by the high voltage power lines affect the electrochemical characteristics of the X70 steel pipeline and accelerate the corrosion of the pipeline. Voir les détails
Mots clés : Electromagnetic pollution, high voltage power line, induced current density, X70 steel pipeline, corrosion, Finite Element Method, electrochemical impedance spectroscopy.
Comparative Performance Study between DTC_C and DTNC Multi-level Inverter Fed DSIM
A comparative performance study between the classical direct torque control (DTC_C) and that of a direct torque control improved by applying the technique of artificial intelligence based on the neural network (DTNC) is proposed in this paper. The command is applied to a double-stator induction machine (DSIM) fed by a multi-level inverter. Simulation results of the speed control of the machine and the improvement of the torque and the flux by reducing the fluctuations are studied by illustrating the DTNC merits compared to the classical DTC_C. Voir les détails
Mots clés : A double-Stator Induction Machine, Direct Torque Control, Neural Network, Multi-level Inverter.
A summary of Vibration analysis techniques forfault detection and diagnosis in bearing
Bearing is one of the most critical components ofrotating machinery .They are employed to support and rotate theshafts in rotating machinery. Therefore; any fault in the bearingscan lead to losses on the level of production and equipments aswell as the creation of an unsafe working environment forhumans. For that reason, the bearing fault diagnosis has receivedconsiderable attention from the research and engineeringcommunities in recent years. The purpose of this study is toreview the Vibration analysis techniques and explore theircapabilities, advantages and disadvantage in monitoring rollingelement bearings. Voir les détails
Mots clés : Vibration analysis, bearing Fault diagnosis, Fast Fourier Transform (FFT), Envelope Analysis (EA), Short Time Fourier Transform (STFT), Empirical Mode Decomposition (EMD)