Electrical Power Engineering

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https://hdl.handle.net/20.500.11888/13968

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    A NEW METHOD FOR OPTIMALLY DESIGNING THE POWER DISTRIBUTION NETWORK OF GRID-CONNECTED PHOTOVOLTAIC POWER PLANT
    (An-Najah National University, 2024-02-11) Assi, Hiba Bashar
    Photovoltaic (PV) systems are attractive renewable energy source for rural electrification and distributed power generation. However, the capital cost of these systems as compared to non-renewable energy sources is still a challenging issue. Thus, many researchers have focused on enhancing the efficiency and the feasibility of photovoltaic systems. This research proposes an optimum methodology for designing the AC power distribution network for grid connected photovoltaic systems considering solar inverter size and location, as well as cable’s size and configuration. The main aim of the proposed method is to offer the shortest cables length and path; achieving a higher efficiency and feasibility in the overall assessment. The suggested approach follows a heuristic method, starting by generating numerous inverter combinations for analysis. For each combination, the total length of cables is calculated considering all feasible inverter locations, aided by Python code to ensure precision. Ultimately, the method identifies the optimal inverter location that results in the shortest cable lengths. A 900 kWp grid connected photovoltaic system is chosen as a case study in this research. Results show that a 23% reduction in total cable length as compared to the conventional approach is achieved by the proposed method. Meanwhile the proposed method offered a better configuration of required solar inverters (size and location). Such a method is very useful for designing photovoltaic system AC and DC distribution networks and exceed and the conventional and intuitive methods.
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    THE IMPACTS AND MITIGATION STRATEGIES OF REVERSE POWER FLOW IN DISTRIBUTION ELECTRICAL NETWORK WITH HIGH PENETRATION OF RENEWABLE ENERGY SYSTEMS
    (An-Najah National University, 2024-10-15) Khalefeh, Mai
    The increasing penetration of renewable energy systems (RES), particularly distributed generation (DG) such as solar photovoltaic (PV), has transformed modern power distribution networks. While this technology offers environmental and economic benefits, it also introduces significant technical challenges. One of the most critical issues is reverse power flow (RPF), which occurs when the generation from distributed sources exceeds local demand, causing power to flow back toward the electrical distribution network. This thesis addresses the impacts of reverse power flow due to high penetration in the electrical distribution network; A detailed analysis is conducted to assess how RPF affects voltage profiles and transformer losses. Through ETAP simulated an electrical distribution with 33 buses , 14 step-down transformers with 10KV /0.38KV rating and 19 loads connected to the buses. The network simulation was done by adding a solar PV energy system and addressing the benefits, then increasing the number of solar PV arrays connected to buses to reach PV penetration at various levels of 20%,40%,60%, in PV penetration no existing to reverse power flow, the buses’ voltages rising to an acceptable levels and this effect improves the electrical network and reduces the transformers losses ,but if any solar PV arrays connected to a bus and generated power exceeds the demand load that connected to that bus a reverse power flows towards the distribution transformer causing losses and rising in voltage. The network was simulated by reducing the load demand to reach PV penetration levels of 109% , and190% ,the reverse power flow amounts was increased with the increase in PV penetration to high levels .and this case occurred when the solar PV system generated power in peak times while the load demand is light .high level of PV penetration produced many impacts as voltage rising issue and transformers losses issue .various mitigation strategies were proposed as BESS (battery energy storage system ), load shifting ,and zero export devices and smart inverters. Assessment was done for each mitigation strategy and choosing between these solutions depends on the specific grid conditions, regulatory framework, and available financial resources.
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    ASSESSMENT OF WIND ENERGY POTENTIAL IN PALESTINIAN TERRITORIES
    (An-Najah National University, 2024-06-24) Solaiman, Motasem Qasem
    The Occupied Palestinian Territories (OPT) face significant challenges due to a high dependency on imported conventional energy sources, including petroleum and approximately 90% of its electrical energy needs from Israeli companies. This dependency results in elevated energy costs and susceptibility to price fluctuations. Amidst these challenges, the energy dilemma has a vital solution in renewable energy. with wind energy representing an underutilized yet promising resource within the OPT. Despite its global significance, wind energy's potential remains largely untapped in the OPT due to a limited number of studies, professional capacity constraints, and geopolitical barriers, alongside the high costs associated with wind energy technologies. These factors have led to a palpable sense of frustration and the perception of wind energy projects as impractical within the region. This study uses exacting scientific procedures to thoroughly examine and assess the OPT's potential for wind energy. Employing the Weibull distribution method, The goal of the study is to present a thorough summary of the state of wind resource evaluations as of right now., explore existing wind energy conversion technologies suitable for the OPT, and present detailed wind characteristics for specific regions under study. Additionally, it aims to identify the most viable locations for wind turbine installations and determine the most appropriate turbine types for these areas. Through this approach, the research endeavors to offer substantive insights and recommendations to overcome the challenges facing wind energy implementation in the OPT.
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    A HYBRID FIREFLY-GENETIC ALGORITHM FOR THE OPTIMAL COORDINATION OF DIRECTIONAL OVERCURRENT RELAYS
    (2023-02-19) Tareq Husam Foqh
    Theoretical background: Directional overcurrent relays are applied for power system protection to ensure safe, reliable, and efficient operation. The coordination of directional overcurrent relays is non-linear and highly constrained optimization problem. The main goal of the optimization is to minimize the summation of operating times of primary relays, by setting optimal values for decision variables as time multiplier setting (TMS) and plug setting (PS). Aims: The main objective of this research is to develop a hybrid optimization algorithm which consists of modified firefly algorithm and genetic algorithm to find better solutions. Methodology: First, this study modified the original firefly to obtain a global solution by updating the firefly's brightness and to avoid the distance between individual fireflies from being too far. Additionally, the randomized movements were controlled to produce a high convergence rate. Second, the optimization problem is solved using standard genetic algorithm. Finally, the solution obtained from the modified firefly algorithm is used as the initial population for the standard genetic algorithm. The modified firefly algorithm, genetic algorithm and hybrid firefly-genetic algorithm have been tested on IEEE 3-bus, 8-bus, 9-bus and 15-bus networks. Main Results: The results indicate the effectiveness and superiority of the proposed algorithms in minimizing the overall operating time of primary relays compared to other algorithms mentioned in the literature for directional overcurrent relays coordination. Conclusion: Compared to modified firefly algorithm and standard genetic algorithm, the proposed hybrid algorithm has minimized coordination interval time between primary and backup relay pairs. Keywords: Directional overcurrent relays optimization, Hybrid algorithms, Firefly algorithm, Genetic Algorithm.
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    DESIGN A FUZZY LOGIC CONTROLLER TO CONTROL ACTIVE POWER FILTER FED BY MULTILEVEL INVERTER AND PHOTOVOLTAIC
    (2023-09-11) Ghadeer Ahmad Abduh
    New electrical systems commonly use nonlinear loads, which increase harmonic pollution in the primary power system. When power electronic equipment with semi-conductors is utilized, harmonic currents occur, affecting quality of power and generating non-sinusoidal currents taken from the AC sources. This result in a current discontinuity and an increase in the system's harmonics. Harmony in the power network generates a variety of issues, including voltage deformities at the Point of Common Coupling (PCC), altering peak and RMS values of line used, and a variety of other issues. In addition to the challenges caused by harmonic current, reactive power is another problem with the quality of the electricity in the power system. To improve the quality of the power delivered to the network, electrical filters must be employed to cancel harmonics and reactive power. The power quality is developed using a variety of filter topologies, including passive, active, and hybrid. A shunt active filter is employed in this project to increase the quality of the electric power. This active filter can perform a variety of tasks, including reducing harmonics, adjusting reactive energy, improving Power Factor (PF), inserting real power source. The primary goal of this project is to apply a fuzzy logic controller to optimize the performance of the Shunt Active Power Filter in order to lower harmonic distortion. To decrease the harmonic current and raise the power factor to unity, the Fuzzy Logic Controller for the three-phase Shunt Active Power Filter is intended to replace the Proportional Integral controller. The results were confirmed from the calculated values of the THD of the source currents. The THD was reduced from 16.67% before using the APF to 2.62 % after using the APF for PI controller and 16.67% to 1.42% for FLC. These results of the THD for FLC is even better than the results obtain of PI controller. MATLAB/SIMULINK has been used in this study to combine various renewable energy sources with a 27-level H-Bridge multi-level inverter with a shunt active power filter. The system has been built to function in a variety of operational scenarios. Keywords: Fuzzy Logic Controller, Shunt Active Power Filter, Photovoltaic,Multilevel Inverter, Total Harmonic Distortion.