Electrical Power Engineering

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    PV multi-level based Grid
    (2021) Shoubi Razan; Shashtare Zenat; Nofal Yasmeen
    PHOTOVOLTAIC (PV) power supplied to the utility grid is gaining more and more visibility, while the world’s power demand is increasing. Solid state inverters have been shown to be the enabling technology for putting Photovoltic PV system into the grid. 2-level inverters are used to convert the DC voltage optained from the Photovoltic system to AC voltage fed to the utility. However, the use of 2-level inverters causes an increase in the Total Harmonic Distortion (THD) and other Power quality issues due to the harmonics injected by the such inverters. Increasing attention has been paid to multilevel dc/ac inverters in recent years to obtain output voltage of high quality. One of the more flexible topology is the asymmetric cascaded H-Bridge multilevel inverter, which will be employed in the project to improve the quality of the output voltage by reducing the harmonic contents. The project consists of two modules: power circuit and control circuit. The power circuit consists of two H_bridges forming an eight- level inverter. The ratio between DC voltage of the two H-Bridges will be 1:3. This will help to generate maximum number of levels and generate output near sinusoidal. The control circuit include the using of a microcontroller and current and voltage sensors to generate PWM signal to H-bridges and control the injection of real and reactive power inject to the grid. The whole structure of the project will be shown in Figure 1 ( Attached is a file showing the figure) . Experimental and simulation results using matlab /simulink will be presented to show the improving of the power quality using the multilevel inverter.
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    Analysis of Power Conversion Stages and Efficiency Improvement Possibilities for Grid Connected Pv System.
    (Eman Omar Mahmoud Abu Hani, 2018-04-10) Abu Hani, Eman
    In this thesis the improvement of large scale PV system conversion efficiency is presented. Mainly the inverter efficiency is considered to be improved by testing two different configurations of 100 kWp PV. The first configuration consists of one single centralized inverter and the second one of master-slave inverter. A Mathematical model is developed by MATLAB software to model the inverter efficiency as a function of input power then the power output is calculated by using hourly solar radiation and ambient temperature data over one year in Palestine. The simulation results show that the annual average energy production using the single centralized inverter is 181.26 MWh/year, while the annual production of master-slave inverter is 184.5MWh/year. In addition, by considering only the inverter efficiency the annual efficiency of DC/AC conversion stage for first system is 96.7% and for the second system is 98.4%. Economic analysis shows that the additional investment in master-Slave configuration instead of using single centralized inverter can be covered within six and a half years.
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    Utilization Landfill Gas from ZF Landfill for Electricity Generation
    (جامعة النجاح الوطنية, 2019-12-24) Snouber, Ahlam Nwaeif
    In this research, we have studied the feasibility of using anaerobic digestion technology of Municipality Solid Waste to produce biogas and generate electricity at Zahrat Al-Finjan Landfill in northern Palestine. Solid waste is one of the environmental problems in urban areas of Palestine. Municipal Solid Waste Reduction, Reuse and Recycling (MSW) are technologies for dealing with household solid waste but are not being used effectively in our country. Since MSW is very rich in energy, its use as a renewable energy source is one of the most important economic projects that the Palestinian Authority seeks to implement if its economic viability is proven and the financial resources will be available. The investigation results of energy efficiency and environmental impact of biogas utilization in ZF landfill are satisfactory enough both for electric energy production and for its contribution to greenhouse gas mitigation. This thesis has two main objectives. First, to determine whether active extraction of Zahrat Al- Finjan landfill gas would produce adequate electric power for utilization and grid connection. The second objective is to estimate the reduction of greenhouse gas emissions. However, to optimize the designing of a plant fed by biogas, it was very essential to quantify biogas production over several years. This research found that the average biogas production per year at Zahrat Al- Finjan landfill is more than 13 million cubic meters, enough to run 3.9 MW plants, and annual energy production of more than 34 GWh/year, and around 18 thousand tons of CO2 reduction per year.
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    ANALYSISAND IMPROVEMENT OF NABLUS ELECTRICAL DISTRIBUTION NETWORK BY ADDING A NEW CONNECTION POINT IN SARRA VILLAGE AND TWO TRANSFER SUB-STATIONS TO FEED THE NETWORK
    (جامعة النجاح الوطنية, 2022-01-18) Qassab, Mohammad
    Lack of electric power sources is one of main problems in Palestine since the population increased dramatically and the required electric power exceeded the permissible limit. In fact, since the Israeli-Electric Company is almost the primary source of electricity, therefore the electric power are limited. The Palestinians suffer from a shortage of electric power due to increasing of electrical power demand, but Israel Electric Corporation does not keeping up with the increasing demand. Nablus also suffers from a shortage of electric power due to the existence of new buildings and the sharp increase of population. In addition, the total electric power supplied to Nablus from connection points has the capacity of 65 MW, but electrical loads reached their peak especially in winter. Consequently, North Electrical Distribution company (NEDCO) cuts off some loads from certain areas in Nablus network for periods of time that exceed an hour per day in order to reduce the pressure on the other connection points in the same electrical network because loads exceed the permissible limit. This leads to failure in electrical transformers as well as in transmission lines and devices. At SARRA connection point, which is one of the connection points of Nablus, the capacity of the substation is 80 MW, and the used capacity is 40 MW. In this study, the researcher aims to examine the analysis and improvement of Nablus electrical distribution network by adding a new connection point in SARRA village and two distribution sub-stations to feed the network. There, a distribution substation was added in two areas with a capacity for 20 MW to each substation, named: Nablus Al-Jadida and An-Najah National Hospital. In fact, the electric power capacity has been raised to 105 MW for the city of Nablus. In this study, the problem was solved considerably by providing new areas with electric power and redistributing the loads from other connection points located in the Nablus city, especially in the eastern industrial area, and new overhead and underground electric transmission lines have been established. The value of the electric capacity supplied from the connection points to the city of Nablus has decreased, and there is a possibility of future expansion and supplying areas in the future due to the presence of electric energy capacity at the new connection points, according to the results found in this study. Also, economic feasibility of the project was prepared and the initial cost value has been calculated.
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    Impact of Battery Charging Station on Electrical Distribution Network: Study of the Harmonic Currents Impact and Mitigation Possibilities
    (جامعة النجاح الوطنية, 2021-01-28) Omar, Reem Talat
    This thesis focuses on the impacts of electrical vehicle charging stations on electrical power networks. The generated harmonic currents have negative impacts on the power system components causing more losses and voltage profile modifications. This thesis represents the impacts of PHEV charging stations in different configurations of electrical networks. Each charging station consists a three phase full wave rectifier with DC/DC converter for charging regulation. A simulation model was programmed based on MATLAB Simulink to perform harmonic analysis in two different electrical configurations AC and DC electrical networks. In AC distribution systems the impact of charging stations in three different modes shows that the voltage is reduced from 400 V to 336V while the total harmonic distortion of current and voltage reduced to 20.4% and 6.73% respectively. On the other hand, in DC electrical networks the total harmonic distortion of current and voltage are 24% and 10.9% respectively. Moreover, ETAP software was used to analyze the impacts of charging stations on electrical network in two different cases to localize the charging station downstream and upstream. Finally, in order to mitigate the harmonics, passive filter was designed to mitigate the harmonic currents which resulting to reduce that the total harmonic distortion of current and voltage reduced to 9.2% and 5.3% respectively.