M. BELKHIRI Salah

This article explores the implementation of advanced maintenance practices and technologies for electric motors, focusing on the integration of Digital Twin technology, workforce training, and predictive maintenance strategies. A Digital Twin a virtual replica of an electric motor is utilised to simulate real-time performance, predict potential issues, and optimise maintenance schedules. The article highlights the importance of structured workforce training programs, adherence to standardised protocols, and comprehensive documentation to enhance maintenance efficiency and operational standards. Simulation results demonstrate the significant impact of these practices, with maintenance efficiency improving by up to 95% within six months. The benefits of improved maintenance practices are analysed, emphasising increased reliability, enhanced efficiency, cost savings, and extended equipment lifespan. Mathematical models are proposed to quantify these benefits, including logistic growth functions for efficiency improvement and cost-saving equations for financial analysis. A case study illustrates the successful implementation of predictive maintenance using IoT-enabled sensors and vibration analysis in a manufacturing plant. The study highlights key results, including a 30% reduction in unplanned downtime, a 15% improvement in energy efficiency, and a 25% increase in motor lifespan. Simulation findings further validate the effectiveness of predictive maintenance, showcasing linear trends in downtime reduction, energy efficiency improvement, motor lifespan extension, and maintenance cost optimisation.

Capacitive accelerometers are widely used in various applications due to their high sensitivity and precision in measuring acceleration. The performance of these accelerometers can be significantly enhanced through effective modeling and optimization techniques. This article explores the process of defining a parameter array for the simulation of capacitive accelerometers to improve their performance and reliability. The simulation provides valuable insights into temperature effects, facilitating the development of more accurate and durable sensors. This article also emphasizes the importance of precision in manufacturing, achieving tight tolerances, and maintaining control over all aspects of the production process. Finally, this article discusses the optimization of power consumption through careful design, component selection, and power management strategies. These optimizations lead to the creation of energy-efficient capacitive accelerometers that can operate over extended periods.

This study presents a comprehensive investigation into the application of vibration sensors coupled with advanced signal processing techniques for the diagnosis and maintenance of mechanical systems. The core of the research is centered around the integration of several signal processing techniques, namely filtering, the Fourier transform, wavelet analysis, decimation/interpolation, and spectral analysis. Each of these methods contributes uniquely to improving data quality, isolating noise, and extracting significant diagnostic features from the raw sensor signals. Filtering eliminates irrelevant frequency components, while the Fourier transform provides a global frequency overview. Wavelet analysis offers multi-resolution insight into transient signal behavior, and decimation/interpolation helps in optimizing signal resolution. Spectral analysis is further used to isolate characteristic frequencies associated with specific faults. A key contribution of this study is the quantitative evaluation of signal enhancement through these methods. The proposed signal processing framework resulted in a signal-to-noise ratio (SNR) improvement of 20 dB and enabled fault detection with an accuracy exceeding 90%, demonstrating the effectiveness of the approach in real-world scenarios. Moreover, the study bridges the gap between theoretical signal processing and practical maintenance needs by validating the techniques on experimental data acquired from a centrifugal pump testbed. This not only confirms the applicability of the methods but also highlights their potential for real-time condition monitoring in industrial environments. By effectively combining multiple signal processing tools, the study underscores a significant improvement in the early detection of faults, reduction of false alarms, and enhancement of maintenance planning. These results contribute meaningfully to the advancement of predictive maintenance strategies, allowing for proactive intervention, reduced downtime, and improved operational reliability of mechanical systems in demanding industrial settings.

This work presents the design, fabrication, and performance evaluation of resistive pressure sensors using a PDMS matrix integrated with graphene as a conductive filler. The sensors exhibit high electrical conductivity and mechanical flexibility, making them suitable for flexible, wearable applications. Comprehensive simulations, supported by SEM analysis, reveal a uniform dispersion of graphene within the PDMS matrix, forming a continuous conductive network essential for sensor functionality. The sensors demonstrated high sensitivity (0.58 kPa⁻¹) and a predictable logarithmic relationship between pressure and resistance, making them ideal for precise pressure measurements across a broad range (0.5 kPa to 100 kPa). Mechanical testing confirmed the sensor’s durability and flexibility over 10,000 bending cycles, showcasing its resilience under repeated deformation. The sensors’ ability to detect finger pressure, pulse signals, and handwriting patterns underscores their versatility for use in wearable devices, health monitoring systems, and human-machine interfaces. The optimization of graphene content (2 wt%) was found to balance conductivity and flexibility, ensuring optimal performance. This work highlights the potential of 3D printing and graphene-based composites for developing high-performance, flexible sensors, with promising applications in next-generation wearable electronics and healthcare monitoring systems.

Piezoelectric materials are critical for sensing, actuating, and energy-harvesting applications. This study provides an in-depth analysis of the thermal effects, mechanical properties, and advancements in these materials to improve performance under diverse environmental conditions. Lead Zirconate Titanate (PZT) offers high sensitivity over moderate temperature ranges but suffers from thermal depolarization at elevated temperatures. Quartz, known for its exceptional thermal and mechanical stability, is suitable for high-temperature applications, though its sensitivity is lower. Lead-free ceramics like Bismuth Sodium Titanate (BNT) and Bismuth Ferrite (BiFeO₃) present eco-friendly alternatives, balancing sensitivity and durability. PZT remains ideal for high-sensitivity needs due to its mechanical stiffness and durability, while BNT and BiFeO₃ are promising for specific applications with BiFeO₃ excelling in stiffness and BNT offering good thermal cycling resilience. Doping PZT with niobium (Nb) and lanthanum (La) significantly enhances its thermal performance and mechanical stability, with Nb improving thermal stability and La enhancing cyclic stress resistance. Polymer materials such as Polyvinylidene Fluoride (PVDF) provide flexibility and thermal stability but exhibit lower sensitivity compared to ceramics. The selection of piezoelectric material depends on specific application requirements, including operating temperature, sensitivity, and mechanical resilience. Composites, which offer a balance of sensitivity, flexibility, and mechanical stability, bridge the gap between ceramics and polymers. Advanced processing techniques such as sintering, doping, and crystal orientation control allow for fine-tuning of material properties, improving sensitivity, damping behavior, and long-term thermal stability. In conclusion, composite materials present an effective solution for diverse piezoelectric applications, with further research into microstructural design and advanced simulations paving the way for improved performance in dynamic conditions.

This article explores the design and optimization of piezoelectric sensors, focusing on the impact of electrode configuration and material fatigue on sensor performance. Piezoelectric sensors are pivotal in various applications, including medical instrumentation, aerospace, and structural health monitoring. This study emphasizes the importance of electrode placement, shape, and size in enhancing charge collection efficiency while minimizing parasitic effects, such as leakage currents and unwanted capacitance. We utilize various modeling techniques, including the finite element method (FEM) and analytical models, to simulate charge density distribution and electric field behavior. Simulation results reveal a direct relationship between applied mechanical stress and generated charge density, as well as insights into the electric field distribution across the sensor. Additionally, we investigate the effects of damping and isolation techniques in reducing noise and improving reliability, demonstrating that increased damping can lead to decreased displacement response while enhancing stability. The findings highlight the balance required between sensitivity and stability in piezoelectric sensor design. This work contributes valuable insights into optimizing piezoelectric sensors for improved performance across diverse applications, with implications for future research on advanced materials and novel configurations.

Purpose
The purpose of the maintenance application is to improve the parameters of the system’s operational safety, such as reliability, maintainability, security, and availability.

Design/methodology/approach
The design of maintenance should include a plan to identify, monitor, and maintain the electric pump unit of the company. The approach should involve a combination of preventive, predictive, and corrective maintenance activities. The organization should develop processes for tracking and reporting on the performance of the electric pump unit.

Findings
The main objective of our work is to make an in-depth statistical study of a chosen system’s faults (failure history). According to the practical training that we did at the company, the chosen system is the electric pump unit, and its availability and reliability are estimated. The improvement of the electro-pump group reliability is made by the proposal of solutions based on the maintenance concerning the most faulty elements that have been extracted by the ABC method.

Research limitations/implications
The main limitation of a maintenance strategy is that it cannot guarantee the effectiveness of preventive maintenance activities.

Originality/value
A maintenance strategy that focuses on preventive maintenance and regular inspections can be very effective in reducing downtime, improving efficiency, and reducing the cost of repairs.

This paper presents a novel approach to optimizing damping in capacitive sensors to improve their accuracy, response time, and noise reduction. Both simulation and experimental methods were employed to evaluate the effectiveness of the proposed optimization techniques. The sensor’s accuracy was assessed by comparing the final displacement values from both the simulation and experimental data, yielding minimal discrepancies. The response time, defined as the time required for the sensor to stabilize after oscillations, was significantly improved by adjusting damping rates. Additionally, signal noise was analyzed by quantifying the error between the simulated and experimental data, revealing small, random deviations primarily caused by external disturbances. The results demonstrate that optimizing the damping characteristics enhances sensor performance, making the system more responsive, accurate, and reliable for high-precision applications. This study confirms the potential of simulation models for predictive analysis and optimization, offering insights into improving capacitive sensor designs for diverse industrial and technological applications.

Introduction In this work, we explored the capacitive accelerometer in depth by highlighting its advantages over other accelerometers. However, a major challenge associated with using capacitive accelerometers lies in choosing the appropriate frequency range. Method Incorrect selection of the frequency range can cause several problems. It can decrease the accuracy of the accelerometer, increase the measurement error, and increase power consumption. To overcome these challenges, we undertook detailed modeling of the physical behaviour of the capacitive accelerometer. This modeling takes into account the mechanical and electrical properties of the sensor, including its mass, its rigidity, and the characteristics of its capacitive circuit. By simulating the developed model, we analyzed how the accelerometer reacts to different frequencies of vibratory movements. Result This analysis led to the extraction of an important mathematical relationship that links the natural frequency of the accelerometer to the frequency of the vibratory movements to which it is subjected. Using this mathematical relationship, we determined the optimal frequency range for capacitive accelerometer operation. This precise determination of the frequency range makes it possible to significantly reduce the measurement error by avoiding resonance regimes and ensuring that the sensor operates in its maximum precision zone. Conclusion Additionally, this approach helps improve overall measurement accuracy and minimize sensor power consumption by avoiding inefficient operating conditions.

In this article, we have chosen to explore the performance of the piezoresistive accelerometer, favoured for its comparative advantages over other accelerometers. Our approach includes modelling this accelerometer according to the law of motion and validating the model through simulation tests and experimental trials. With this approach, we can determine the optimal damping rate and frequency range for the piezoresistive accelerometer, the optimisation of these parameters is crucial to maximise the performance of the accelerometer in various operating conditions, ensuring high sensitivity and fast response while minimising distortions or errors in the collected data. These optimal values of damping rate and frequency range guarantee precise and reliable accelerometer measurements. This paper provides a comprehensive overview of sensor design principles and signal processing methods from a theoretical standpoint. Beginning with sensor design, we delve into the foundational aspects of transduction principles, emphasising the conversion of physical quantities into electrical signals. The selection and optimisation of sensing elements are explored, highlighting material properties, geometrical considerations, and packaging strategies to ensure sensitivity, linearity, and robustness.

This work offers a thorough method for integrating advanced modeling, electrode design, signal processing, and material selection techniques to maximize the performance of capacitive accelerometers. Key performance measures, including noise reduction, sensitivity, and range, can be systematically analyzed and simulated to forecast how design decisions would affect the overall behavior of the sensor. Advanced electrode designs greatly increase capacitance, which results in more precise and trustworthy sensor readings. These designs include optimizing the shape and using high-permittivity materials. Furthermore, to guarantee that the accelerometer's output precisely represents actual motion even in noisy surroundings, noise reduction strategies including filtering and digital signal processing methods are essential. Additionally, calibration is emphasized as a critical step in preserving measurement accuracy over time and accounting for environmental changes and sensor drift. The choice of material, with an emphasis on thermally stable and high-permittivity materials, is crucial in determining the capacitance, sensitivity, and durability of the sensor. The study offers a paradigm for the creation of capacitive accelerometers that perform better across a variety of applications by striking a balance between these variables.

This work offers a thorough method for integrating advanced modeling, electrode design, signal processing, and material selection techniques to maximize the performance of capacitive accelerometers. Key performance measures, including noise reduction, sensitivity, and range, can be systematically analyzed and simulated to forecast how design decisions would affect the overall behavior of the sensor. Advanced electrode designs greatly increase capacitance, which results in more precise and trustworthy sensor readings. These designs include optimizing the shape and using high-permittivity materials. Furthermore, to guarantee that the accelerometer's output precisely represents actual motion even in noisy surroundings, noise reduction strategies including filtering and digital signal processing methods are essential. Additionally, calibration is emphasized as a critical step in preserving measurement accuracy over time and accounting for environmental changes and sensor drift. The choice of material, with an emphasis on thermally stable and high-permittivity materials, is crucial in determining the capacitance, sensitivity, and durability of the sensor. The study offers a paradigm for the creation of capacitive accelerometers that perform better across a variety of applications by striking a balance between these variables.

To choose the appropriate frequency range, it is necessary to understand the physical behavior of the sensor in different situations. The natural frequency of a capacitive accelerometer is an integral part of its design and material characteristics, and it influences the response of the sensor to various frequencies of vibrational inputs. If the frequency of the vibrating movements is too close to the natural frequency of the accelerometer, this can lead to resonance, which leads to strong oscillations and considerable measurement errors. During our research, we created a comprehensive model to represent the operation of the capacitive accelerometer. This model includes the essential elements that impact sensor performance, such as mass, damping and stiffness, as well as the electrical characteristics of the capacitive sensing mechanism. The study of this model under different conditions made it possible to observe the reaction of the accelerometer to various frequencies of vibration inputs. These simulations allowed us to relate the natural frequency of the accelerometer to the frequency of the vibratory movements. It is essential to take this relationship into account to define the ideal frequency range for the accelerometer. By entering this link, it is possible to choose a frequency range that prevents resonance and reduces measurement errors, improving the accuracy and reliability of the sensor output.

Capacitive accelerometers are essential components in a wide range of electronic devices, enabling crucial functionalities such as touch sensitivity and proximity detection. Ensuring optimal accuracy is crucial for their effective performance in various applications. A key factor in this accuracy is the frequency margin, a parameter that significantly influences the sensor's ability to detect and respond to changes in capacitance.
In this article, we will delve deeply into strategies aimed at optimizing capacitive sensors with a focus on improving their frequency margin. By exploring the methodologies and techniques that enhance the sensor's ability to operate within an ideal frequency range, we aim to improve the measurement accuracy of capacitive accelerometers by reducing measurement errors and power consumption. This optimization process involves meticulous calibration of sensor parameters such as sensitivity, resonance frequency, and damping factors to maximize performance under various environmental conditions. The new capacitive accelerometer structure improves sensitivity, linearity, and accuracy through advanced measurement setups and design, offering high-performance acceleration measurements suitable for various applications and reliable data collection and calibration.

Vibrational analysis plays a pivotal role in predictive maintenance and condition-monitoring, providing the capability to identify emerging issues before they escalate into equipment failures, unplanned downtime, or safety hazards. Attaining maximum accuracy in vibrational measurements is crucial for the efficacy of these analyses. In this study, our objective is to enhance the measurement accuracy of the piezoelectric accelerometer, a fundamental transducer in vibrational analysis. We propose a novel formula that establishes a connection between the measurement accuracy of the sensor and the displacements of vibrational movements. This improvement is designed to elevate the precision of vibration analysis, reducing errors in fault detection and optimizing the outcomes of condition-based preventative maintenance initiatives. The overarching goal is to enhance the reliability of vibration analysis techniques, ensuring a more robust and efficient approach to machine condition monitoring and maintenance planning.

Vibrational analysis plays a pivotal role in predictive maintenance and condition-monitoring, providing the capability to identify emerging issues before they escalate into equipment failures, unplanned downtime, or safety hazards. Attaining maximum accuracy in vibrational measurements is crucial for the efficacy of these analyses. In this study, our objective is to enhance the measurement accuracy of the piezoelectric accelerometer, a fundamental transducer in vibrational analysis. We propose a novel formula that establishes a connection between the measurement accuracy of the sensor and the displacements of vibrational movements. This improvement is designed to elevate the precision of vibration analysis, reducing errors in fault detection and optimizing the outcomes of condition-based preventative maintenance initiatives. The overarching goal is to enhance the reliability of vibration analysis techniques, ensuring a more robust and efficient approach to machine condition monitoring and maintenance planning.

Reliability optimization is a process aimed at improving the effectiveness and efficiency of maintenance activities within an organization. This optimization can concern various aspects, including failure prevention, resource management, cost reduction, and improving the operational availability of equipment. In this work, our study aims to implement a comprehensive maintenance strategy for the 1600T press at Algal+ company with the primary objectives of preventing breakdowns, minimizing unplanned downtime, optimizing productivity, extending the lifespan of equipment, ensuring safety, and improving the competitiveness and profitability of the company. The problem of reliability and availability of the 1600T press at the Algal + company can be addressed by a systematic approach to industrial maintenance. By adopting a holistic approach to industrial maintenance, Algal+ company can improve the reliability and availability of its equipment, thereby reducing unplanned downtime and optimizing overall productivity. By systematically applying FMECA to the 1600T press, the optimization efforts become data-driven and focused on addressing the most critical risks. This, in turn, significantly contributes to optimizing the reliability and availability of the equipment, reducing unplanned downtime, and enhancing overall operational efficiency.

Reliability optimization is a process aimed at improving the effectiveness and efficiency of maintenance activities within an organization. This optimization can concern various aspects, including failure prevention, resource management, cost reduction, and improving the operational availability of equipment. In this work, our study aims to implement a comprehensive maintenance strategy for the 1600T press at Algal+ company with the primary objectives of preventing breakdowns, minimizing unplanned downtime, optimizing productivity, extending the lifespan of equipment, ensuring safety, and improving the competitiveness and profitability of the company. The problem of reliability and availability of the 1600T press at the Algal+ company can be addressed by a systematic approach to industrial maintenance. By adopting a holistic approach to industrial maintenance, Algal+ company can improve the reliability and availability of its equipment, thereby reducing unplanned downtime and optimizing overall productivity. By systematically applying FMECA to the 1600T press, the optimization efforts become data-driven and focused on addressing the most critical risks. This, in turn, significantly contributes to optimizing the reliability and availability of the equipment, reducing unplanned downtime, and enhancing overall operational efficiency.

Objective: The objectives of this paper are to highlight the significance of vibration analysis, especially in predictive maintenance for rotating machinery, and to emphasize the importance of detecting bearing defects that may result in machinery failure.
Methods: The proposed methodology combines the use of time-synchronous averaging (TSA) with existing vibration analysis techniques. TSA involves aligning vibration data with specific events or phases in the machinery's operation, such as shaft rotation. By synchronizing the data in this way, the methodology aims to reduce noise and enhance the signal related to bearing defects, making them more distinguishable.
Additionally, the methodology incorporates well-established vibration analysis techniques. These techniques may include frequency analysis, amplitude modulation analysis, waveform analysis, and others commonly used in the field of condition monitoring and predictive maintenance.
Results: The results of the analysis begin with waveform analysis, which involves examining the shape and pattern of vibration signals captured from the pinion. This analysis provides valuable insights into the dynamic behavior of the pinion gear, including any variations or abnormalities in its motion. Moreover, the use of synchronized waveforms is crucial in this analysis. By aligning the vibration data with specific events or phases in the gear mesh cycle, such as tooth engagement, the analysis can pinpoint moments when potential faults or wear in the machinery may occur. This synchronization allows for a more precise assessment of the vibration signals, enabling the detection of irregularities that may indicate underlying issues with the pinion or other components of the machinery.
Conclusion: A pivotal aspect of the methodology involves envelope spectra analysis, significantly enhancing diagnostic capabilities. This analysis identifies fault patterns that might not be readily apparent in conventional vibration analysis. The incorporation of envelope spectra proves instrumental in proactive maintenance, enabling early detection of potential issues. This, in turn, contributes to the overall reliability and optimization of machinery performance.

A piezoelectric sensor is a type of transducer that utilizes the piezoelectric effect to convert changes in pressure, acceleration temperature, or force into an electrical charge. This unique property makes piezoelectric sensors valuable for a wide range of applications in various industries. In this work, the main focus is on studying the effects of piezoelectric materials and exploring the functionality of piezoelectric sensors. The physical behavior of the sensor is thoroughly examined and a mathematical formula relating the accuracy of the sensor to relative movement or vibratory displacement is derived. The developed model is verified through simulations and experimental tests. By carefully selecting the appropriate damping rate, it is possible to enhance the parameters of the piezoelectric sensor and advance the technique of vibratory analysis. Overall, this research aims to enhance our understanding of piezoelectric materials and sensors, and how they can be effectively utilized in various applications involving vibratory analysis. The findings from this study can contribute to better design and implementation of piezoelectric sensors, improving their accuracy and effectiveness in capturing and analyzing vibratory movements.

Le contenu de ce document est destiné aux étudiants en 3e année Licence de ELM ainsi à toute les personnes intéressées par l’étude, caractéristiques et l’évolution des matériaux industriels au département de génie électrique à l’Université de Mohamed Boudiaf de M’sila. Il s’inspire de nombreux ouvrages et références bien plus complets, ainsi que divers documents de collègues universitaires. Ce document est bien sur incomplet : il manque des chapitres entiers, des démonstrations, des exemples, mais il présente plusieurs notions de base concernant les matériaux utilisés en électrotechnique. Toute remarque est la bienvenue, même en ce qui concerne les probablement nombreuses fautes d’orthographes.
Pour plus de détaille et d’aprofondement veuillez revoir les références.
Le but de ce travail est d’accompagner l’étudiant ou l’apprenant depuis l’apprentissage des notions de base jusqu’aux notions avancées utilisées couramment dans le domaine industriel.
Parallèlement, il peut également convenir à une formation ciblée, à la compréhension de points particuliers ou de principes généraux, souvent préalables à la spécialisation en génie électrique.

Active Vibration Control (AVC) stands out as a prominent technique in the realm of vibration mitigation and structural dynamics. Unlike passive vibration control methods that rely on dampers or isolators, AVC systems actively manipulate forces or motions within a structure in real-time to counteract undesirable vibrations. In this paper, the main distinguishing characteristic of AVC lies in its proactive approach, wherein control algorithms and actuators are employed to actively sense and respond to dynamic changes in the system. The application of Newton’s second law allows a model of the vibration sensors operation, followed by simulations to improve their performance, which contributes to the advancement of the active vibration control system by enabling more precise detection and measurement of vibrations.

Ce Module est réservé pour la présentation des différentes méthodes et techniques numériques dans le but de faire :
- Exposer et acquérir un ensemble de méthodes numériques permettant de résoudre des problèmes impossibles par des approches analytiques.
- Savoir transposer la connaissance mathématique pure à un ordinateur aux performances finies.
- Résoudre numériquement des problèmes dont la solution analytique est connue ou non.
- Analyser le comportement des méthodes.

The purpose of a piezoelectric sensor is to measure the vibratory movements of structures by the direct effect of the piezoelectric material. In this paper, the operating principle of the piezoelectric sensor is defined in detail, and it is translated as a mathematical model (i.e., the modeling of this type of sensors). This developed model relates the accelerometer electrical parameters with their mechanical parameters, and simulation of this model allows the appropriate sensor damping rate to be chosen which minimizes error and improves accuracy and sensitivity. The proposal of a new relation links the relative frequency with the piezoelectric sensor natural frequency that makes it possible to minimize the resonance phenomenon effect, to facilitate the suitable choice of the sensor and to protect it.

An accelerometer is a transducer that, on its own or in conjunction with electronics, instantly transmits an electrical signal corresponding to the force applied to its base. To measure vibrations with a capacitive accelerometer, it is important to know its accuracy, exact sensitivity, and reliability but sometimes the phase of the signal or the frequencies of interest. This paper chooses the capacitive accelerometer through its advantages over other types. The modeling of this type of accelerometer has been the subject of extracting from new formulas linked to the characteristics of the capacitive sensor and the simulation of the developed models makes it possible to minimize the measurement error, maximize the measurement accuracy, and reduce the electrical energy consumption by the appropriate choice of the damping rate and the frequency margin. A new equation for damping rate according to error is extracted by using the developed model. This equation makes easier the choice of damping rate that will minimize error to a very low value and maximize accuracy. This developed model is confirmed by experimental tests and finally, a new design of the capacitive accelerometer is proposed.

Power quality improvement in infected power grid using solar SAPE based on DPC with disturbance rejection principle

Numerical tools appear to be essential for modeling and designing devices based on superconducting materials. In this article different simulation results are presented, using a computer code based on the finite element method adopted for the resolution of the electromagnetic equations, in the case of an axisymmetric two-dimensional problem, with this code we study the variations of the different electromagnetic quantities. The second generation superconductor has been modeled as an interesting diamagnetic material as inductive pulse sources. The performance in magnetic field resistance, energy storage and thermal stability of the ribbon, known as YBCO, makes it possible to broaden its field of application. Two categories of machines have been proposed and analyzed, the first is classic and the second uses a superconducting ribbon. In addition, a comparative study between the two proposed models is carried out and the results are analyzed and discussed.

support de cours s’adresse aux étudiants en Master II de l’ELM - Semestre 3 du département Génie électrique à l’université de Mohamed Boudiaf de M’sila.
Il a pour but :
 De voir tous les problèmes liés à l’électricité notamment les chocs électriques (contacts directs, contacts indirects).
 De savoir les dangers et les mesures préventives dans les installations électriques.
 De considérer les causes des incendies et explosions d’origine électrique dans installations électriques.
 D’assurer une veille réglementaire efficace et évaluer la conformité de l’entreprise par rapport aux normes et réglementations en vigueur.
 De sensibiliser et faire adhérer chacun aux politiques de gestion des risques.
 D’initier les étudiants aux notions de base de l’habilitation électrique.

The performance of superconducting current limiters associating the short-circuit phenomenon depends on the structure of the superconducting material envisaged and on the way of inserting it into the electrical network. The multi-layer structure, which uses thin “sandwich” layers, is found to be of interest in the search for fault current limiting power. In this paper, we present some numerical results of the magnetic behavior of superconducting fault current limiters (SFCLs). The numerical problem of this study is solved using the control volume method (CVM). The electromagnetic and thermal coupling is ensured by an alternative algorithm. To describe the relationship between the electric field and the current density inside the thin-film superconductor, we chose to use the power law model widely used in simulation work.

This document presents a comparative study of solid and thin-layers superconducting fault current limiter (SFCL) for electrical network transient stability improvement. Two applications of transient stability appraisal are presented in this article: the first shows the efficiency of the massive and thin-layers SFCL in series with a generator; the second uses SFCL installed in series with a transmission line. SFCL can only be used during the period from the fault occurrence to the fault clearing; the modeling and the effect of SFCL have been investigated to have higher benefits for the power system. In the present work, modification of the admittance matrix method is used for modeling of SFCL; critical clearing time (CCT) has been used as an index for evaluated transient stability. The results of the simulations showed the benefit of designing a superconducting current limiter from thin layers. These considerably improve not only the thermal stresses of the current limiter during the process of limiting the fault current by the significant decrease in temperature but also by its important contributions for the improvement of the transient stability of the electrical network. Thus, they can considerably extend the life of a second-generation superconducting current limiter. The modeling of the network tests will be made by PSAT under the MATLAB environment.

Condition-based maintenance is the most advanced form of maintenance because it is based on the actual state of the machine. It allows for better manage the interventions according to the state of the machine, its wear, or its degradation. The most widely used technique for this type of maintenance is vibration analysis because it detects the majority of faults in rotating machines. In this work, we studied the piezoelectric sensor which is considered the first element of the vibration measurement chain, and the modeling and simulation of the latter allowed us to improve their characteristics and their performance.

Study and simulation of SAPF interconnected to a PV system based on DPC with
disturbance rejection principle,

Numerical tools appear to be essential for modeling and designing devices based on
superconducting materials. In this article different simulation results are presented, using
a computer code based on the finite element method adopted for the resolution of the
electromagnetic equations, in the case of an axisymmetric two-dimensional problem, with
this code we study the variations of the different electromagnetic quantities. The second
generation superconductor has been modeled as an interesting diamagnetic material as
inductive pulse sources. The performance in magnetic field resistance, energy storage and
thermal stability of the ribbon, known as YBCO, makes it possible to broaden its field of
application. Two categories of machines have been proposed and analyzed, the first is
classic and the second uses a superconducting ribbon. In addition, a comparative study
between the two proposed models is carried out and the results are analyzed and discussed.

In this work, the effects of piezoelectric materials are explained and the piezoelectric sensor is described. The physical behavior of the sensor is modeled and extracted a formula relates the accuracy as a function of relative movement (vibratory displacement). The model developed is validated by simulation and by experimental tests and the appropriate choice of the damping rate makes it possible to improve the parameters of the piezoelectric sensor and to progress the vibratory analysis technique.

In this article different simulation results are presented, using a computer code based on the finite element method adopted for the resolution of the electromagnetic equations, in the case of an axisymmetric two-dimensional problem, with this code we study the variations of the different electromagnetic quantities. The superconductor was modeled as a diamagnetic material with a power law for the relationship between current density and electric field. We have however attached great importance to the comparison of the results obtained for the two machines (conventional and superconducting). Therefore, a comparative study between the two proposed models is carried out and the results are analyzed and discussed.

The choice of piezoelectric material for a mechanical resonator sensor development is essential in terms of sensitivity, compatibility with the environment in which it will operate (high temperatures, environment acidity, …), complexity of the manufacturing processes implemented and costs involved. In this paper, piezoelectric detection is studied to understand mechanical resonator sensor operation principle and express it into a mathematical model. Validation by simulation tests of the developed model of measurement accuracy and measurement error as a function of relative vibration movement is performed. Applying this model, sensor characteristics and performance will be improved therefore, a new mechanical resonator sensor design can be proposed. The aim of these improvements is to obtain more accurate results and provide accurate information on vibratory level. A comparative study is conducted to show the effectiveness of the obtained results compared to the literature. These results have also demonstrated that a suitable and appropriate choice of damping rate improve the accelerometer operation and enhances the vibratory analysis technique.

This study presents a new strategy for implementing the superconducting fault current limiter SFCL in order not only to limit short - circuit currents but also to improve the stability of electrical networks in the presence of faults. The calculation of the impedance that the limiter must introduce into the test network at the moment of the failure is obtained from a three-dimensional computation code, developed and implemented under MATLAB environment where the formulation in magnetic vector potentials A and scalar potential Electric V is adopted to solve the electromagnetic problem and the heat diffusion formulation is adopted also to solve the thermal problem. The coupling is ensured by an alternating algorithm and the numerical resolution of the problem is ensured by the method of the finite volumes in its three-dimensional version in order to avoid certain problems of numerical convergence linked to the strongly nonlinear character of the problem to be solved. The modeling of the network tests will be made by PSAT under the environment MATLAB.

In this work, the mathematical model suitable for the operating principle of the piezoelectric
accelerometer is extracted then this model which connects the accuracy and the measurement
error according of the frequency ratio and the damping rate is validated by simulation. The model
developed makes it possible to improve the performances of the accelerometer such as precision,
sensitivity and reliability as well as to propose a new conception of the latter. A comparative study
is made to show the importance of our results compared to literature, these results have showed
that a suitable and appropriate choice of damping ratio develops the accelerometer parameters and
enhances the vibratory analysis technique.

Industrial electrotechnics represents a considerable potential market for superconducting materials. Among the feasible applications, the limitation of the fault current will probably be the first to find an industrial departure. We present in this work the results of the simulations of the magnetic and thermal behavior of a fault current limiter designed from a high critical temperature superconducting layer. The results are obtained from a 3D computation code, developed and implemented under MATLAB environment where the formulation in magnetic vector potentials A and electrical scalar potential V are adopted to solve the electromagnetic problem and the heat diffusion formulation is also adopted to solve the thermal problem by the method of the finite volumes. The results showed the interest of designing a superconducting fault current limiter. The development of a simulation model that describes the behavior of the (SFCL) has also been implemented in a nine-bus network.

Les performances de limiteurs de courant supraconducteurs associant le phénomène de court-circuit dépendent de la structure du matériau supraconducteur envisagé et de la façon de l’insérer au réseau électrique. La structure à plusieurs couches qui utilise des couches minces « en sandwich », se révèle intéressante dans la recherche de pouvoir de limitation du courant de défaut. Le présent article décrit les résultats des simulations du comportement magnétothermique d’un limiteur de courant de défaut conçu à partir des couches minces et une couche supraconductrice à haute température critique. Les résultats sont obtenus à partir d’un code de calcul tridimensionnel, développé et implémenté sous environnement MATLAB par la méthode des volumes finis (MVF) où la formulation en potentiels vecteur magnétique A et en potentiel scalaire électrique V sont adoptées pour résoudre le problème électromagnétique et la formulation de diffusion de la chaleur est adoptée aussi pour résoudre le problème thermique. Le couplage est assuré par un algorithme alterné. Les résultats des simulations ont montré l’intérêt de concevoir un limiteur de courant supraconducteur à partir des couches minces. Ces derniers améliorent considérablement les contraintes thermiques du limiteur de courant durant le processus de la limitation du courant de défaut par la diminution importante de la température, ainsi ils peuvent prolonger considérablement la durée de vie d’un SFCL.

Le présent travail visera l’étude du comportement magnétothermique d’un limiteur de courant supraconducteur de type massif, le modèle qui permet de décrire ce comportement est basé sur la résolution par la méthode des volumes finis (MVF) des équations électromagnétiques et thermique. Le couplage et les paramètres dépendant de la température sont pris en considération lors de la résolution. Les résultats sont obtenus à partir d’un code de calcul tridimensionnel, développé et implémenté sous environnement MATLAB où la formulation en potentiels vecteur magnétique A et en potentiel scalaire électrique V sont adoptées pour résoudre le problème électromagnétique et la formulation de diffusion de la chaleur est adoptée aussi pour résoudre le problème thermique.

The behavior of the superconducting fault current limiters
SFCL used in Electrical Network is largely determined by
the geometry properties and the type of the bulk
superconductors used. In this work we present a numerical
analysis of the electromagnetic and the thermal behavior of
the SFCL and the influence of geometrical properties of the
bulk superconductors of rectangular shape used in an
electrical network The results are obtained from a threedimensional
computation code, developed and implemented
under MATLAB environment where the formulation in
magnetic vector potentials A and electrical scalar potential
V are adopted to solve the electromagnetic problem and the
heat diffusion formulation is also adopted to solve the
thermal problem. The coupling is ensured by an alternating
algorithm and the numerical resolution of the problem is
ensured by the method of the finite volumes in its threedimensional
version in order to avoid certain problems of
numerical convergence linked to the strongly nonlinear
character of the problem to be solved.
1. Introduction

L'électrotechnique industrielle représente pour les matériaux supraconducteurs un marché potentiel considérable. Parmi les applications faisables, la limitation des courants de défaut (court - circuit) sera probablement la première à trouver un départ industriel. Les caractéristiques mises en jeu sont tout à fait spécifiques des supraconducteurs, à savoir la grande différence existante entre un état passant à hausse densité de courant, et un état bloquant à haute résistivité, obtenu dès que le courant dépasse un seuil donné. Il est ainsi possible de protéger le réseau électrique contre toute élévation du courant au-delà d'une valeur spécifiée. Le but de ce travail est de mettre en évidence les propriétés électromagnétiques de ces matériaux et de présenter une modélisation du phénomène de limitation de courant
de défaut. Le développement d’un modèle de simulation qui décrit le comportement du limiteur de courant Supraconducteur (SFCL) à été également implanté dans un réseau à neuf (09).jeux..de..barres.

Nous présentons dans cet article les résultats des simulations du comportement magnétique et thermique d’un limiteur de
courant de défaut de deuxième génération conçu à partir des couches minces et une couche supraconductrice à haute
température critique. Les résultats sont obtenus à partir d’un code de calcul tridimensionnel, développé et implémenté sous
environnement Matlab où la formulation en potentiels vecteur magnétique A et en potentiel scalaire électrique V sont adoptées
pour résoudre le problème électromagnétique et la formulation de diffusion de la chaleur est adoptée aussi pour résoudre le
problème thermique. Le couplage est assuré par un algorithme alterné et la résolution numérique du problème est assurée par la
méthode des volumes finis dans sa version tridimensionnelle afin d’éviter certains problèmes de convergence numérique liée
au caractère fortement non linéaire du problème à résoudre. Les résultats des simulations ont montré l’intérêt de concevoir un
limiteur de courant supraconducteur à partir des couches minces. Ces dernières améliorent considérablement les contraintes
thermiques du limiteur de courant durant le processus de la limitation du courant de défaut par la diminution importante de la
température, ainsi ils peuvent prolongé considérablement la durée de vie d’un limiteur de courant supraconducteur de
deuxième génération.