Doctorat
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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 oscillationItem 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 healthyItem 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 applicationItem 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