Browsing by Issue Date, starting with "2023-06"
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Item “Design & Control of Distributed Generations for Micro-Grid Applications”(IOE Pulchowk Campus, 2023-06) Poudel, Yam KrishnaClimate change, its influence on the environment, and natural resources scarcity necessitate scientific research and creative technical solutions for a modern power system. This research aims to develop scientific and technological approaches to “green” technologies, which are environmentally beneficial and long-lasting. Energy and power supply are major priorities. The design and control of distributed power generation systems for micro grid applications was the prime focus of this thesis. A 20 KW micro grid is designed to operate in both modes, albeit primarily in the isolated mode, where solar photovoltaic, wind energy, and battery energy storage modules are included. Maximum Power Point tracking (MPPT) was used to obtain the highest power production from solar photovoltaic and wind energy sources. We used lithium-ion batteries of nominal 48V to store energy produced by PV and wind systems. To maintain a constant voltage of 220V on the DC bus, bi-directional converters were used to control charging and discharging process. The inverter, which is based on a voltage sourced inverter (VSI) was used for supplying power to the AC load. Novel control approach methods were used to maintain power quality and frequency resynchronization. Synchronous reference frame theory (D-Q) with voltage oriented dual control was applied as a control algorithm. Bio inspired metaheuristic technique Particle swarm optimization (PSO) was applied for PID tuning. Islanded mode and grid feeding conditions of micro grids were analyzed, discussed and presented. The results reveal that the system performs satisfactorily under varying generation and load consumption. The PV module consists of total 14 parallel strings and the series connected module per string was set at 6. The output variations were observed from 13KW to 21KW with variations of irradiance of and temperature. The wind power output was 6 KW to 2KW with variations of Speed 12- 8m/s. Lithium-ion batteries rated 420Ah with a nominal discharge current of 182.6887A were used with a normal voltage of 48V. The load variations used were 5KW to 45KW. Higher order filter (LCL filter) was utilized to enhance power quality and performance of two different micro grid cases (i) Islanded mode and (ii) Grid feeding mode was analyzed. This research has a significant impact on the development of micro grids.Item FACULTY PUBLICATION MANAGEMENT SYSTEM(I.O.E. Pulchowk Campus, 2023-06) AWAL, RUJA; MAKA, SANTOSH; POKHREL, SURAJ; DHAKAL, SUYOGFaculty publication management system is an integrated web application software that allows administrators to effectively manage all the faculty publications from record keeping to publication data analytics and visualization. Faculty evaluation system is also a part of the system that allows administrators to evaluate faculty members, lecturers and professors. This report presents design and development of the systems. Due to absence of a unified faculty publication management system, research publications of faculty members were spread across various research publication sites like GoogleScholar, ReserachGate, IEEE, etc and it became a tedious task for administrators to keep track of publications and generate associated reports for administrative purposes. Our system scrapes all the relevant data from such websites and presents user with a unified system to add, edit, approve, search, sort and generate reports of such publications as per faculty members or departments. The system additionally allows a user to perform data analytics and visualizations with bar chart and pie chart of research publications across faculty members and even specific departments. Later, the system uses the publication data of faculty members along with other evaluation metrics like years of service and objective feedback form data provided by students for evaluation of the user. Also, title based clustering of faculty members help to create clusters of members with similar research areas.Item Voltage Profile Improvement and Power Loss Reduction by DG Placement in a Distribution Feeder in Western Nepal(IOE Pulchowk Campus, 2023-06) Rawat, Youb RajA power system is composed of various components that work together to generate, transmit, and distribute electricity to consumers. The distribution system completes the process of delivering electricity to the ultimate users or customers. Radial, loop and network distribution system are basic three types of distribution system design. The radial distribution system is simple and cheapest to build and is extensively used in sparse populated area. However, due to the existence of higher resistance, longer length and lower voltage level in the distribution system network, electrical energy is continuously lost. The distribution system is often viewed as the weakest link in the power system. The ratio of resistance to reactance in a distribution system is higher as compared to transmission system and significant voltage drop along a distribution feeder can cause substantial power and energy losses. Due to Joules effect power loss occurs in distribution feeder account for as much as 13% of the generated energy (1). Therefore, reducing losses in the distribution system is a major challenge for many utility companies worldwide. As per NEA Annual Report 2020/021, in INPS distribution system loss is 10.86%. Reduction of loss in distribution system has been an important area of focus from the time when the development of interconnected power systems. To increase overall effectiveness of the electrical power distribution system, it is crucial to reduce active power loss in the system. By supplying a portion of the reactive demand locally with the aid of capacitors, the active power loss caused by the reactive component of branch current can be decreased (2). Similarly with the help of technique “Reconfiguration of distribution system” power loss of a distribution system can also be reduced (3).Item Optimal Transmission Pricing Scheme with Consideration of System Reliability(IOE Pulchowk Campus, 2023-06) B.C, HIKMAT BAHADURThe power industry has become an essential driver of economic progress in our country. Over the past couple of decades, the electricity market has experienced significant transformations in its structure, primarily due to deregulation, which has fostered competition among power generators. However, this deregulation has presented several challenges, including the allocation of transmission embedded costs, effective management of losses, and addressing congestion issues within the integrated market. Within this framework, the cost of transmitting electricity imposed on consumers assumes a critical role as it serves as a variable that can be controlled within the power system. This variable provides valuable signals to generator owners in making decisions about the location, type, and timing of their installations. Moreover, it plays a crucial role in defining the overall efficiency of the market. The primary objective of transmission pricing methodologies is to ensure fair competition within the electricity sector and offer reliable economic indicators. As part of this process, users are required to pay fees for network access and usage to the entity responsible for the network. Various methodologies exist for determining the pricing of transmission usage and access, each serving its purpose in promoting a robust and equitable electricity marketItem Numerical Analysis of Pile wall for Excavation Support in Soft Ground(I.O.E. Pulchowk Campus, 2023-06) Puri, MadanCantilever pile walls are a type of earth support structure that can provide advantages in minimizing excessive deformation during ground excavation. In multiple scenarios, the construction of basements for new buildings or structures is planned in close proximity to existing older buildings. In such instances, the surrounding area of the old building, known as the influence zone, exerts lateral earth pressure onto the newly excavated area. To withstand and contain this lateral earth pressure, a cantilever pile wall is constructed. Kathmandu, the capital and most populous city of Nepal, is characterized by buildings constructed on soft ground consisting of grey to dark silty clay and clayey silt. As the city moves towards the development of high-rise buildings, it becomes crucial to ensure proper excavation without causing any damage to the existing buildings in close proximity to the construction site. Therefore, well-designed cantilever piles are being studied using finite element analysis, considering both 2D and 3D modeling techniques. The objective is to analyze and design effective cantilever pile systems that can accommodate the requirements of the upcoming high-rise developments while safeguarding the nearby structures. The resulting straining effects, such as bending moments, shear forces, normal forces, and lateral support forces, can vary between 2D and 3D analyses. Additionally, the deformation of the wall and the subsidence profile may differ when comparing 2D and 3D analyses.Item SMART EV CHARGER WITH REACTIVE POWER COMPENSATION(I.O.E. Pulchowk Campus, 2023-06) Ghimire, Ankit; Dhungel, Ashish; Thapa, Deepak; Bhandari, NirajanThe voltage drop is a serious issue that the grid is facing at present due to the penetration of a large number of EVs. For this at present STATCOMs and Capacitor banks are used, however STATCOMs are expensive and Capacitor Banks have less reliability. In this situation we came up with an idea to embed the functions of such compensating devices into the charger itself in order to increase the system reliability and reduce the use of such expensive devices. This paper illustrates the overall procedure of the prototype design of the system and an EV charger that regulates the voltage at the user end. As our final year project, we sought to develop a smart EV charger that compensates for the reactive power in the grid and maintains the voltage at the user end while charging the vehicle battery simultaneously. The project was carried out first in simulation (MATLAB) and then proceeded with hardware implementation right from the scratch. At first, we simulated the design in a Three phase system and observed the result in MATLAB Simulink. The charger works as a boost rectifier thus we were able to charge a 60 KW charger at unity power factor. While charging, the node voltage was dropped significantly low below the standard limit. Thus, in order to regulate the voltage at the node of connection. We supplied the reactive power to the grid through the charger.Item An Analysis of Reliability-Technical Losses In 33 kV Radial Distribution/transmission system In Far Western Region of Nepal(I.O.E. Pulchowk Campus, 2023-06) Joshi, KapilThis thesis presents a model approach for minimizing the transmission and distribution line power loss along with the analysis of reliability of the lines in electric power systems. Distribution power loss is a measure of the energy lost during the distribution of electricity from the sending end point to the receiving end users. This loss can be noteworthy and has a straight impact on the proficiency and economics of the power system. The proposed approach utilizes a combination of control algorithms and optimization techniques to effectively minimize the distribution power loss. Experiments on realistic power system models prove the effectiveness of the proposed method in reducing distribution power loss and improving the overall efficiency of the power system. This thesis also presents a model for improving the reliability of electric power systems through reducing distribution power loss. Reliability of power systems is a critical aspect as power outages can have significant economic and societal impacts. The proposed approach utilizes a combination of control algorithms, different calculation indexes, optimization techniques and redundancy strategies to minimize the distribution power loss and improve the overall reliability of the power system. The method is tested on realistic power system models, and results show the significant improvement in reliability metrics such as system availability and frequency of power outages. This approach can be a valuable tool for power system operators to enhance the reliability of power systems and ensure continuity of power supply to end-users.Item Performance Enhancement of Low Voltage Distribution Network by Optimal Inverter Control of Solar PV System(IOE Pulchowk Campus, 2023-06) Chaudhary, SurendraThe thesis highlights the increasing contribution and impact of grid-connected photovoltaic (GCPV) systems, a type of renewable energy source, in electrical distribution systems. GCPV systems offer several advantages to customers and distribution network utilities. They enable consumers to fulfill their own electricity demand, reduce electricity bills, and even feed surplus power back into the grid. Additionally, GCPV systems can act as backup systems when there is insufficient or no PV generation. The increasing number of network-connected PV inverters also allows for their usage as Volt Ampere Reactive Compensators, which can regulate distribution network voltage and eliminate the need for expensive compensation devices like capacitor banks. However, introducing a large number of small-scale rooftop gridconnected PV systems with varying ratings into the distribution network can lead to technical challenges. One major problem is the voltage rise along the distribution network, causing reverse power flow, especially during low power demand and high PV generation conditions. This voltage rise limits the network's ability to accommodate more PV connections. Another issue is the possibility of voltage drop along the network during periods of no PV generation, particularly when there is high power demand and no PV generation.Item “Future Energy Mix of Nepalese grid and its effect on Power System”(I.O.E. Pulchowk Campus, 2023-06) Lamichhane, BharatEnergy mix refers to the combination of different sources in to the grid to increase the power system reliability. In Nepal most of electricity is from hydro power plant. There are other alternative sources of energy to produce an electricity but hydro is much more available resources to produce electricity. There are different types of schemes of hydro power plants which can be operated to meet base load, intermittent load and peak load. In current situation, there is some deficit of energy. So country is importing energy from India via different points. The generation pattern of hydro power plant is highly dependent in natural phenomenon of rain and hence the flow of water in river. In wet season the generation from run off river hydro power plants is high but in dry season the generation is low. Due to this there is large unbalance may arise in the system. The energy surplus deficit analysis will give an overview of future energy situation in advance which will be very helpful for energy planner to take necessary decision. Energy surplus analysis for fiscal year 2087/088 and for fiscal year 2092/093 under three scenario viz: under 4.5 % with only half of all generation license issued RoR/ PRoR projects in operation within fiscal year 2087/088 and half of generation license applied projects(RoR/PRoR) comes in operation till fiscal year 2092/093 (Scenario 1); under 4.5 % Economic growth rate with all generation license issued projects in operation within fiscal year 2087/088 and all generation license issued and generation license applied projects comes in operation till fiscal year 2092/093 (scenario 2) and under 7.2 % Economic growth with all generation license issued projects in operation within fiscal year 2087/088 and all generation license issued and generation license applied projects comes in operation till fiscal year 2092/093.Item Optimal Placement of Distributed Generation in Distribution Networks Using Grey Wolf Optimization(I.O.E. Pulchowk Campus, 2023-06) Das, Mahendra KumarThis thesis presents a comprehensive study on the integration of Distributed Generation (DG) into power systems, with a focus on the optimal placement and sizing of DG units. The research aims to investigate the impact of DG on system stability and power loss reduction, as well as to propose a novel optimization algorithm for the optimal placement and sizing of DG units. The integration of distributed generation (DG) is expected to play an important role in the electric power system planning and market operations. As DG are integrated into the distribution system, it results in operating situations that hampers the conventional system without generation directly connected at the distribution level.Item ACTIVE CELL BALANCING APPROACH FOR EFFICIENT BATTERY MANAGEMENT SYSTEM(I.O.E. Pulchowk Campus, 2023-06) Sharma, Aakriti; Adhikari, Anusha; Adhikari, Bibek; Pandey, PratikThis project proposes a novel approach for improving the efficiency of battery management systems through active cell balancing using the Kalman filter algorithm and build a hardware prototype model for testing and validation of the results. The goal of this project is to develop a system that can extend the lifespan of batteries by ensuring that each cell is charged and discharged evenly. The proposed system includes an active balancing circuit that uses the Kalman filter algorithm to estimate the state of each battery cell and determine the optimal charging and discharging currents. This approach is designed to reduce the energy loss associated with passive balancing circuits, which can be a significant source of inefficiency in battery management systems. The project includes simulation studies using MATLAB and Simulink and experimental results to demonstrate the effectiveness of the proposed system. The simulation studies will be conducted to optimize the design of active balancing circuit and Kalman filter. The experimental results confirm the effectiveness of the Kalman filter algorithm in estimating the state of each battery cell and optimizing the charging and discharging currents. The experimental studies will involve testing hardware prototype model using actual battery cells and the developed active balancing system.Item “Chemical Analysis and Biological Activities of Crude Extracts and Green Synthesized Silver Nanoparticles of Medicinal Plants from Mustang and Kaski Districts of Nepal(Institute of Science & Technology, 2023-06) Khanal, Lekha NathMedicinal plants contain numerous secondary metabolites with significant biological activities. Due to diverse geographical and climatic conditions, several indigenous plants that comprise unique phytochemicals having a wide spectrum of biological assets are found in Nepal. This study aims to synthesize, characterize, and evaluate the biological activities of silver nanoparticles (AgNPs) by using some of the active medicinal plants of the study area. Methanol extracts of the selected plants were evaluated for antioxidant, antibacterial and α-amylase inhibition activities by using the DPPH radical scavenging, agar well diffusion, and CNPG3 methods respectively. The chemical profiling of essential oil isolated from the aerial parts of Ephedra pachyclada and Ayenia grandifolia was performed by the GC-MS analysis. This study exposed the phytochemical and biological activities of methanol extract, chemical profiling of essential oil, and green synthesis of AgNPs by using an aqueous extract of A. grandifolia for the first time. Among the 22 plants evaluated, Rubus ellipticus, E. pachyclada, Pyrus pashia, Drynaria coronans, Mimosa rubicaulis, and Ziziphus mauritiana extracts exhibited significant antioxidant properties with the highest activity of A. grandifolia (IC50 = 12.87 ± 0.14 µg/mL). The GC-MS analysis of the essential oil (EO) of stem barks of A. grandifolia contained di-n- octyl phthalate (28.39%), 2,6,11 trimethyl dodecane (15.77%), 4,6 dimethyl dodecane (12.79%), and o-guaiacol (7.07%). The methanol extracts of R. ellipticus and P. pashia exhibited the highest antibacterial activity. The resazurin microtiter assay method revealed the MIC and MBC of the methanol root extract of R. ellipticus as 3.12 and 12.5 mg/mL respectively against Staphylococcus aureus ATCC 25923. The methanol stem bark extract of P. pashia exhibited the highest α-amylase inhibition activity with an IC50 value of 24.22 ± 0.10 µg/mL. From the preliminary investigation, A. grandifolia, R. ellipticus, P. pashia, and Z. mauritiana which exhibited the highest biological activities were used for the fabrication of AgNPs. Each of the plant extracts and AgNO3 (1 mM) in the ratio of 1:9 by volume were mixed with constant stirring at lab temperature (25 ± 2ºC), and neutral pH with constant stirring over a magnetic stirrer. The change of color into light brown within an hour was considered a visual indication of the growth of AgNPs which was further confirmed by the appearance of sharp SPR peaks in the UV-visible spectra. The UV-visible spectra at different reaction conditions of temperature, pH, and concentration were used to optimize the fabrication of AgNPs. FTIR spectra of the extract and the AgNPs were examined to detect the functional groups responsible for the reduction, capping, and stabilizing of AgNPs. The face-centered crystalline nature of the silver nanoparticles was established by the X-ray diffraction patterns by matching the diffractogram with the Joint Committee on Powder Diffraction Standards (JCPDS file no: 03-0921). It was further confirmed by the selected area electron diffraction (SAED) pattern having four discrete rings corresponding to the crystal planes at 110, 200, 220, and 311. The energy dispersive X-ray (EDX) analysis showed the presence of silver in the highest proportions and trace quantities of oxygen, chlorine, calcium, and carbon in the AgNPs. The surface morphology and nearly spherical shapes were determined by field emission scanning electron microscopy (FESEM) images. Transmission electron microscopy (TEM) was used to confirm the topographical, compositional, and morphological status of the AgNPs. Further, TEM images were used to find the sizes of the synthesized AgNPs which ranged from 28.05 ± 11.8 nm of A. grandifolia extract-mediated AgNPs to 16.73 ± 4.94 nm of Z. mauritiana extract-mediated AgNPs. The antioxidant activities of AgNPs synthesized by using Z. mauritiana (with an IC50 value of 37.02 ± 1.0 µg/mL) and A. grandifolia (with an IC50 value of 142.77 ± 10.75 µg/mL) were found to be nearly twice as potent as their respective crude extracts. The AgNPs synthesized using A. grandifolia demonstrated notable antibacterial activity, whereas its crude extract showed no such activity. The process of transforming plant material into AgNPs not only enhanced their antioxidant and antibacterial properties but also indicated the potential biomedical applications of these plant-based nanoparticles. Further investigation involving the synthesis of controlled-sized AgNPs from other plants, toxicity testing, and exploring potential applications would greatly benefit humanity.