Natural Sciences

Permanent URI for this collection

https://hdl.handle.net/20.500.11888/18293

Browse

Recent Submissions

Now showing 1 - 5 of 89
  • No Thumbnail Available
    Item
    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.
  • No Thumbnail Available
    Item
    IMPACTS OF CLIMATE CHANGE ON THE WATER BUDGET IN THE FARIA CATCHMENT, PALESTINE
    (An-Najah National University, 2025-01-12) Daraghma, Qais
    Studying the climate change impacts on the elements of the hydrological cycle in the Faria catchment is extremely important, given that the region is classified as semi-arid. Many inhabitants of the region depend on agriculture and there is a pressing need to develop the water supply and understand the future of water under climate change owing to the rapid population growth and the expansion of human activities. The study includes analyzing the changes in the climate elements and studying their impact on the hydrological cycle. The study uses SimClim AR6 (Assessment Report) to model the climate change and SWAT hydrological model for a comprehensive analysis of the effects of climate change. Daily climate data for the period (1990-2021) were used for building the hydrological model and the results were calibrated and verified using the SWAT-CUP software. The statistical performance parameters such as Coefficient of Determination (R2) and Nash Sutcliff Efficiency (NSE) enhanced the reliability of the model. The study analyzed the impacts on the core elements (precipitation, minimum and maximum temperatures, relative humidity, solar radiation, and wind speed) using 23 GCM's under the influence of the medium emission scenario SSP2-4.5 and the high emission scenario SSP5-8.5 to investigate the changes in the five elements over time periods of 2060 and 2100. The results revealed a marked decrease in the seasonal precipitation and relative humidity rates, resulting in a decrease in groundwater recharge rates of -8.81% under the SSP2-4.5 scenario until 2060 to -27.43% under the SSP5-8.5 scenario until 2100. Surface runoff rates result between -15.43% under the SSP2-4.5 scenario for 2060 to -43.31% under the SSP5-8.5 scenario for 2100. A marked increase resulted in the future temperature rates and evapotranspiration by 3.14% under the SSP2-4.5 scenario for 2060 to 9.64% under the SSP5-8.5 scenario for 2100. An increase in the solar radiation rates and variability in wind speeds are expected. The results also showed a decrease in water yield rates by -14.31% under the SSP2-4.5 scenario for the 2060 to -42.50% SSP2-4.5 under the SSP5-8.5 for the 2100, significantly threatening water resources in the future. Therefore, there is an urgent need to find plans and strategies to adapt to this phenomenon and develop water efficiency to enhance water sustainability. The study emphasizes the great importance of promoting hydrological and climatic modelling in order to comprehensively understand the extent to which climate changes affect water resources especially in arid and semi-arid regions. It also recommends that cooperation between decision makers and researchers be strengthened in order to develop research meeting the expected challenges of climate change and adaptation to its impacts.
  • No Thumbnail Available
    Item
    IMPROVING DUCTILITY BEHAVIOR OF REINFORCED CONCRETE COUPLING BEAMS IN SPECIAL SHEAR WALLS USING ULTRA-HIGH PERFORMANCE CONCRETE
    (An-Najah National University, 2024-12-31) Hlayel, Aseel
    The coupling beams are critical components that connect the shear walls of a coupled shear wall system. In the last few decades, the ductility of diagonal coupling beams has become one of the most important issues in seismic design. Design codes including the ACI 318 code, provide requirements for designing diagonal coupling beams to avoid failure with a reasonable level of ductility under seismic loads. However, the complex reinforcement detailing that is provided by the design codes causes a time-consuming construction process. This research aims to investigate the use of Ultra-High-Performance Concrete (UHPC) as a substitute for transverse reinforcement while maintaining the inclined bars in diagonal reinforced concrete coupling beams within coupled shear wall systems. The objective is to enhance ductility behavior and reduce construction time by simplifying reinforcement detailing. Numerical simulations using ABAQUS finite element software are performed and validated against published experimental data. Irregularly shaped buildings are selected for the analysis to accurately represent real-world conditions and achieve the study's objective. The main investigated parameters include the coupling beam aspect ratio, the depth of coupling beam and the length of the shear wall. The results show that UHPC-strengthened diagonal coupling beams in the coupled shear walls are capable of dispensing the complete amount of transverse reinforcement in diagonal coupling beams while achieving the required ductility level compared to traditional diagonal coupling beam designs specified by the code.
  • No Thumbnail Available
    Item
    RISK BASED MANAGEMENT OF INDUSTRIAL WASTEWATER IN NABLUS CITY
    (An-Najah National University, 2024-10-13) Afaneh, Ateid
    Industrial wastewater is highly polluting the environment if not handled properly, also affect the wastewater infrastructure for both collection and treatment. Most of consumed water is converted to wastewater from residential, industrial, and commercial uses. Industrial wastewater is a critical concern for all industrial settings that lacks the infrastructure to handle such water. Generally, industrial wastewater in Palestine represents a major challenge to the environment and municipal infrastructure, mainly in the industrial cities like Nablus city. This thesis aims at concluding the most appropriate solutions which prevent or decrease the hazards resulted from industrial wastewater on the wastewater infrastructure and its operation. The research utilized the risk based management approach to propose proactive and reactive barriers for industrial wastewater hazards and impacts. Cost Benefit Analysis was used to estimate the costs and benefits for Nablus municipality for each identified barrier. Risk analysis was carried out to explore the hazards and impacts of industrial wastewater on the infrastructure; Wastewater Network (WWN) in Nablus and Nablus- West Wastewater Treatment Plant (NW-WWTP). Risk evaluation was used to priories the hazards through the calculated risk priority number (or degree of severity) to quantify risk. Results showed that industrial wastewater, which had risk priority number of 9 poses a significant threat to the municipal infrastructure. Infrastructure damage and operational inefficiencies were resulted. To reach this thesis's goal, estimated proposed strategies to reduce negative impacts were discussed in risk control approach. After conducting risk cost benefit analysis for Nablus municipality, it is found that awareness and WWN rehabilitation have to be excluded because their proportion Factor (d) is more than 1, but the other barriers should be executed by the municipality. Since equipment insurance barrier has the smallest d which is 0.0036, it has to be prioritized. Then, to execute the remaining barriers from smallest d in ascending order. Finally, risk based management approach and risk cost benefit analysis options are very useful tools to mitigate and adapt hazards to improve the preparedness and response for Local Governmental Units (LGUs), particularly in the field of wastewater management. The results of this thesis should guide the implementation of effective management practices that ensure environmental protection and infrastructure resilience.
  • No Thumbnail Available
    Item
    ELECTRICAL NETWORK RECONFIGURATION FOR IMPROVING THE RELIABILITY OF DISTRIBUTION SYSTEM CONSISTING OF RENEWABLE ENERGY SOURCES
    (An-Najah National University, 2024-10-10) Thiab, Tahreer
    This thesis evaluates the impact of network reconfiguration on improving the reliability of an electrical network with high PV penetration. The reliability of the electrical network depends on the failure rates of the components installed within it. However, for loads in the network, the failure rate and outage duration can be affected by voltage conditions. In some cases, improving the voltage can reduce the failure rate of loads, but an increase in PV penetration can lead to voltage rise, which may result in a higher failure rate. This thesis discusses how variations in PV penetration impact the reliability indices of the network and explores how reconfiguration of the network can improve its reliability. The case study uses the modified IEEE 33-bus network with a PV penetration level of 70% of the installed electrical loads. Without a PV system, the network experiences voltage drops in loads far from the connection point, leading to a high failure rate due to low voltage. However, with high PV penetration, voltage rise also affects reliability. Reconfiguring the network by connecting additional buses improves voltage conditions in both scenarios, leading to enhanced reliability indices. Without PV, the network's reliability indices are as follows: Average Interruption Rate is 83.847 failures per year, and Average Outage Duration is 1.81 hours. The indices are SAIDI: 151.694, SAIFI: 83.847, EENS: 730.407, and CAIDI: 1.809 hours. With 100% PV penetration but without reconfiguration, the Average Interruption Rate is 54.81 failures per year, and the Average Outage Duration is 1.67 hours. The indices are SAIDI: 91.6206, SAIFI: 54.8103, EENS: 441.153, CAIDI: 1.672 hours. When reconfiguration is added, the network's reliability indices improve: the Average Interruption Rate is 56.7532 failures per year, and the Average Outage Duration is 1.65 hours. The indices are SAIDI: 95.6504, SAIFI: 56.7532, EENS: 460.557, and CAIDI: 1.685 hours. The results, obtained using ETAP software, show that while adding PV reduces losses, it may decrease the reliability of the network if reconfiguration is not implemented. However, with reconfiguration, network reliability is enhanced.