Thèses de Doctorat et Mémoires de Magister

Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/17

Browse

Author: search.filters.author.Bentarzi, Hamid(Directeur de thèse)

Search Results

Now showing 1 - 8 of 8
  • No Thumbnail Available
    Item
    Inter-area oscillation minimization in power system
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2023) Tsebia, Mohammed; Bentarzi, Hamid(Directeur de thèse)
    Inter-area oscillations result from system events coupled with a poorly damped electric power system. These oscillations are observed in large power systems, encompassing groups of generators or generating plants connected by relatively weak tie lines. The low-frequency modes (0.1 to 0.8 Hz) often involve groups of generators or generating plants on one side of the tie oscillating against groups of generators on the other side of the tie bus. These oscillations are undesirable as they lead to suboptimal power flows, inefficient grid operation, and, consequently, grid instability. Mitigating these oscillations is of vital concern. To address inter-area oscillations, equipment such as Static Var Compensators (SVCs) and various Flexible AC Transmission System (FACTS) devices are increasingly employed. The feasibility of these techniques has been made possible by recent advancements in power electronic technology. The involvement of SVCs and FACTS devices in the transmission network is referred to as Variable Series Compensation (VSC). In addition to FACTS devices, the application of Superconducting Magnetic Energy Storage (SMES) to enhance inter-area oscillation damping has been reported. Although Power System Stabilizers (PSS) are present in many generators, their effect is limited to the local area and does not effectively damp out inter-area oscillations. In this research work, it has been demonstrated that inter-area oscillations can be detected using phasor measurement units (PMUs) installed in the power system. In a typical implementation, one or more generators in a system are selected as Remote Feedback Controllers (RFCs). These RFCs receive synchronized phasor measurements from one or more remote phasor measurement units. Analyzing the phase angles provided from multiple sites enables the detection of inter-area oscillations. If an oscillation is detected, a control signal is sent to the generator's voltage regulator, effectively modulating the voltage and damping out the oscillation
  • No Thumbnail Available
    Item
    A new framework of PMU based on FPGA
    (Université M'hamed Bougara : Institut de Génie Electrique et Ectronique, 2023) Mahboubi, Meriem; Bentarzi, Hamid(Directeur de thèse)
    The approach that has been developed in this research work is to generate a configurable input signal, sample it and use the different estimation techniques such as non-recursive, recursive and smart DFT to estimate the phasors. These estimated values would be incorrect if the input signals are at an off-nominal frequency and the phase angles would drift away from the true values. To correct this issue, first, the off-nominal frequency has been estimated using Phasor measurement angle changing technique. Then, it has been used to correct the phasors. Finally, the developed PMU model has been verified and tested with a Grid connected PV system. Smart grid is a modernized electrical supply network in which information is communicated bi-directionally using digital communication technology. SYNCHRONIZED phasor measurement units (PMUs) were first introduced in early 1980s, and since then have become a mature technology with many applications, monitoring, control and protection of the power system networks in real time, which are currently under development around the world. PMUs are able to provide time stamped synchronized measurements of voltage and current phasors using Global Positioning System (GPS) satellites, in microseconds, to maintain the power system network free of faults and hence healthy
  • No Thumbnail Available
    Item
    Automatic voltage regulator performance enhancement in power generation
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2023) Ahcene, Fazia; Bentarzi, Hamid(Directeur de thèse)
    The generation of electrical energy in power systems and islanded networks is generally ensured by the synchronous machine, and hence the enhancement of its dynamic performance during disturbances is increasingly required. The main objective of this research work is to enhance the dynamic performance by maintaining its terminal voltage constant during any instability. This voltage regulation can be ensured via a well-known controller named automatic voltage regulator (AVR) that is generally based on proportional integral (PI) controller. In the first proposed approach, an optimization method such as the particle swarm optimization algorithm (PSO) has been applied to determine the regulator parameters. However, in the second developed method, the AVR is based on Active Disturbance Rejection Control (ADRC) that allows controlling uncertain systems, where the dynamic is not well known such as in this application. Both approaches are tested using different generators with two different ratings under different operating conditions. The first designed AVR is implemented; simulation and test have been carried out under three different operating load conditions using micro-generators such as a 1.5 kVA and 175 W synchronous laboratory power machine with salient pole. This AVR is based on PI controller tuned by PSO algorithm; the obtained simulation and experimental results validate the use of the designed AVR. Then, the second designed AVR test of a second generator of 187 k VA with different exciting system is investigated. However, the designed AVR of the second machine is tested using both techniques PSO base PI and ADRC, the obtained simulation results encourage to use the ADRC control in such application
  • No Thumbnail Available
    Item
    Turbine governor performance improvement in a power generation plant
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2022) Talah, Djamila; Bentarzi, Hamid(Directeur de thèse)
    Governing system is an important control system in the power plant, it regulates the turbine speed, power and hence the grid frequency. Steady state and dynamic performance of the power system depends on the power plant response capabilities in which governing system plays a key role. The aim of this project is to enhance this performance by improving the governing system using recent control techniques. Evidently, a simulation model based on the dynamic mathematical and thermodynamic equations will be considered. The performance of the governing system will be evaluated on the basis of the simulation results. A Combined Cycle Power Generation Plant is considered and a simulation model as well as a governing system model is developed and implemented in order to be used for verifying the performance system. The Modelica language is used as development software tool which is an objectoriented equation-based modeling language that allows for very detailed and consistent representation of system dynamics. Real data collected from the Combined Cycle Power Plant of Ras_Djinet, is exploited in the simulation. The simulation is dealt in Modelica language, and the simulation results are compared to the real data and discussed
  • No Thumbnail Available
    Item
    Protection scheme enhancement of synchronous generator
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2021) Mati, Ayache; Bentarzi, Hamid(Directeur de thèse)
    Synchronous generator is the most important element of a power system and its fast and reliable protection is crucial. One of the most abnormal conditions in a generator is loss of excitation (LOE) which is harmful to both the generator and the power system. This condition should be detected and the generator isolated from the system to avoid generator damage as well as power system instability. This thesis presents a study and comparison of the two conventional LOE protection schemes, negative-offset and positive-offset mho element under different conditions. The results show that the two schemes can detect LOE fault under total or partial LOE conditions, however in terms of speed (fault detection time) the positive offset scheme is faster than the negative offset scheme under all loading conditions. Besides, the two LOE protection schemes are reliable and do not operate under power swing disturbances caused by any type of external faults. Moreover, the impact of the static synchronous compensator (STATCOM) on the positive-offset mho element LOE protection scheme is investigated. The obtained results show that the operation of the positive-offset protection scheme takes more time under the integration of STATCOM in the transmission line. Finally, to reduce this delay time, an enhanced method based on phasor measurement unit (PMU) is proposed. The simulation results show that the new developed method improves the operation of the positive offset mho element LOE protection by reducing the delay time that may be due to the presence of STATCOM
  • No Thumbnail Available
    Item
    Feedback linearization of mimo systems described by a nonlinear state space equation
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2021) Kessal, Farida; Bentarzi, Hamid(Directeur de thèse)
    The idea of feedback linearization is to cancel the nonlinearities and imposing the desired linear dynamics via change of coordinates and feedback so that the linear control techniques can be applied. In this thesis feedback linearization is applied to a class of multivariable nonlinear systems; where the number of inputs divides exactly the number of state. The proposed method consists in converting a nonlinear multivariable system into block controller companion form that is suitable for block pole assignment which amounts to eigenstructure assignment. Necessary and sufficient conditions for input-state linearization have been developed. Comparison study has been achieved between the proposed approach and the feedback linearization for general form of multivariable nonlinear system. To verify the validity and effectiveness of the suggested method, a two-link robot manipulator has been implemented. When a nonlinear system presents a non-involutive property, the approximate feedback linearization is required. The idea of the proposed method consists in representing the original nonlinear system into a state-dependent coefficient form then applying block similarity transformations that allow getting the linearized system in block companion form. Examples have been used to illustrate the application and show the effectiveness of the given approach
  • No Thumbnail Available
    Item
    Oscillation damping improvement using PMU based PSS in power system
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2021) Bousaadia, Baadji; Bentarzi, Hamid(Directeur de thèse)
    The interconnection of power systems and the increase of power transfer are required to meet the increasing demand of electrical energy. These requirements drive the modern power systems closer to their limits of operation. Consequently, low frequency oscillations may arise in systems not affected previously and become a major source of systems instability and limitation factor of power exchange over long distances. One method of mitigation of those oscillations relies on power system stabilizers (PSSs) that can provide effective damping to local oscillation modes by using locally measured signals. However, they lack observability of inter-area modes, which results of poor damping for those modes. In this thesis, a wide area power system stabilizers (WAPSSs), able to effectively damp out inter-area oscillations in large power systems, is adopted. The proposed approach relies on the development of phasor measurement units (PMUs), which provide remote signals as inputs for WAPSSs for real-time implementation. The effectiveness of the proposed approach depends on many considerations. The first step is the selection of suitable control locations and remote signals with high observability to the targeted inter-area modes. To face this requirement, geometric measures of observability and controllability is adopted. The second crucial step is the optimal tuning of WAPSS to achieve adequate damping. A novel metaheuristic algorithm, comprehensive learning bat algorithm (CLBAT), is employed for the tuning process and compared with state of the art metaheuristic algorithms. Finally, the time delays associated with the global signals can deteriorate the performance of the proposed WAPSSs. Thereby a time delay compensators are proposed compensate time delays in wide area measurements based control. The performance of these WAPSSs has been evaluated on the New England/ New York and Two area four machine multimachine systems via eigenvalue analysis, and nonlinear time domain simulations
  • No Thumbnail Available
    Item
    Reliability aware design of integrated circuits
    (Université M'Hamed Bougara : Institut de génie électrique et électronique, 2021) Chenouf, Amel; Bentarzi, Hamid(Directeur de thèse)
    The striking advances in both computer-aided integrated circuit design and manufacturing technologies have paved the way for designing and manufacturing highly complex, high-performance chips integrating more than 100 million transistors into a few square millimeters of silicon. However, this high density has brought with it more challenges for IC designers in terms of their circuits reliability sign-off. In fact, due to the aggressive scaling, and to wear out effects, the electrical parameters of semiconductor devices are shifting over time, causing for ICs the failure to meet the specifications for which they were designed. However, a technology-based solution is not always feasible, mainly because semiconductor engineers usually focus on developing smaller, faster, and less energy-intensive transistors. This compels designers to moderate this degradation and to improve the lifetime of their circuits during the design phase. A simulation of aging becomes therefore essential to predict the performance degradation of the ICs due to temporal variations. Moreover, the introduction of new design techniques which consider reliability as a design constraint as important as speed, area, and power consumption, becomes more than necessary to warranty delivering reliable circuits and systems by adopting design for reliability (DFR) concept. In this prospect, we propose, on one hand, to migrate reliability analysis from device-level to a higher level of abstraction. This allows a better assessment of the induced degradation on the circuits’ performance. On the other hand, we propose a DFR approach to deign reliable circuits. For this PhD thesis we choose, to deal with NBTI, which is one of the most wear-out mechanisms shrinking the lifetime of deep submicron ICs. We present our NBTI circuit-level characterisation results, the implementation of our NBTI model on a commercial simulator. On the other hand, we present an NBTI mitigation approach based on transistor sizing we propose for designing robust 6T-SRAM cells