Mekelle University Institutional Repository
Discover scholarly works, research outputs, and institutional publications.
The Mekelle University Institutional Repository is a digital collection of scholarly and research outputs created by the university's faculty, students, and researchers. This repository provides open access to a wide range of materials, including articles, theses, dissertations, conference papers, books, and more."
By making our research available, we aim to
- Increase the visibility and impact of research conducted at Mekelle University.
- Promote knowledge sharing and collaboration within the academic community.
- Preserve and disseminate valuable scholarly works for future generations
Communities in DSpace
Select a community to browse its collections.
- A central archive for Mekelle University’s institutional abstract books from academic and research conferences.
Recent Submissions
Efficiency Improvement in MV Distribution System through Feeder Reconfiguration (Case Study: Adwa Distribution System)
(Mekelle University, 2025-04-07) Yosef Amaha
The electric power industry is increasingly challenged by rising load demand, aging infrastructure, and the complex spatial distribution of electrical loads, all of which undermine distribution system efficiency. These are especially pronounced in radial networks, where high technical losses and voltage deviations compromise power quality and reliability. Adwa feeder, a 15 kV radial distribution system in Ethiopia, embodies these concerns, with technical losses reaching 940.84 kW, voltage levels dropping to 0.83 per unit, and line loading peaking at 148.14 percent. This study explores feeder reconfiguration using Particle Swarm Optimization (PSO) to improve energy efficiency, voltage stability, and line overloading under varied load conditions.
Load flow analysis was conducted using the Backward/Forward Sweep method in MATLAB under peak, medium, and minimum loading conditions, with total demands of 7,839 kW, 4,710 kW, and 2,160 kW, respectively. PSO identified an optimal switching scheme by opening sectionalizing switches 52 and 71, keeping tie switches 79 and 82 open, and closing 80 and 81. The optimized configuration reduced peak losses by 35.7%, lowering them to 604.87 kW and improving minimum bus voltage to 0.9161 per unit. For medium and minimum loads, losses dropped from 570 kW to 370 kW and from 140 kW to 90 kW, respectively, improvements of 35% and 36% with corresponding voltage profile enhancements.
To validate robustness, Monte Carlo simulations (1,000 iterations, ±10% load variation, ±0.05 PF deviation) confirmed the optimized topology sustained losses near 605 kW and voltages above 0.9 per unit under uncertainty. Furthermore, upgrading the most overloaded segment (Line 1–2) to an AAC 150 conductor further improves losses to 524.32 kW. While this upgrade alone provided an 8.6% gain beyond reconfiguration, the combined effect achieved a total loss reduction of 44.3% from the original case.
These results demonstrate that intelligent feeder reconfiguration, enhanced by PSO and supported by probabilistic analysis, provides a scalable, cost-effective solution for improving performance in radial distribution networks like Adwa's.
OPTIMAL DISTRIBUTED GENERATION INTEGRATION PLANNING (CASE STUDY: SHIRE CITY POWER DISTRIBUTION SYSTEM)
(Mekelle University, 2025-05-21) TSIGE ABRHA
This thesis examines the challenges of power distribution in Shire City, Tigray, Ethiopia, where rapid urban growth driven by industrial, commercial, and residential expansion has increased electricity demand. This rising demand is causing voltage degradation and higher power losses, raising significant stress on the existing infrastructure. The study forecasts future load requirements and explores the addition of renewable energy sources like solar and wind to optimize the distribution network, ensuring a sustainable and reliable power supply. The study uses advanced econometric methods to forecast future load requirements. The results show that peak load demand will rise from 17.29 MW in 2024 to 31.39 MW by 2043, driven by population and economic growth. This increase necessitates significant improvements to both generation and distribution infrastructure. The study further explores the integration of DG to mitigate power losses and improve voltage stability. Optimal distributed generation (DG) integration, as shown by the analysis, yields a significant 91% decrease in active and a 90.84% decrease in reactive power losses while simultaneously optimizing voltage profiles. Cost estimation for the 8.2 MW DG system, comprising photovoltaic and wind technologies, was found to be $3,233,880, with a return on investment expected in 3.77 years. This research demonstrates that integrating DG into the Shire City distribution network offers a viable solution to meet rising electricity demand, reduce power losses, and enhance system stability
Loss Reduction and Voltage Stability Enhancement of Distribution Network through Optimal Allocation of Distribution STATCOM Case Study: (Axum Distribution Network)
(Mekelle University, 2025-06-05) Luel Awetehey
This thesis presents the way of improving the performance of the distribution network by improving the voltage profile and reduces the power loss by integrating D-STATCOM to Axum K4 distribution feeder. D-STATCOM is commonly used in the distribution system for reactive power compensation so that it improves voltage profile, reduces power losses and improves the system voltage stability. The study of this work was conducted on Axum distribution K4 feeder it consists of a total number of Fifty-nine–bus feeders, of which bus-1 is taken as a reference node or slack bus, the other 47 nodes are connected to loads through step-down distribution transformer, and the remaining 12 nodes are common coupling nodes. The voltage profiles of most buses are not in an acceptable range, and the voltage stability index of the buses shows that the network is prone to voltage stability problems. The active and reactive power loss of feeder is 131.72KW and 111.35KVAr respectively. The optimal D-STATCOM allocation in electric distribution system enhances maximizing energy utilization, feeder loss reduction, and voltage stability and profile improvement. To allocate power control variable in the best possible location and with proper size two solution methods are applied. As the first method, the weakest bus of the system was selected for the optimal placement of D-STATCOM using bus based voltage stability index analysis. In the second method, particle swarm optimization (PSO) was applied for selecting optimal placement and size of DSTATCOM. The PSO optimization algorithm formulates a problem by considering system loss reduction, enhancement of voltage profile and voltage stability index of the operated network. A direct load flow analysis also carried out for the purpose of total system loss and bus voltage magnitude determination before and after compensation with D-STATCOM. The optimal allocation problem was tested in different system case based on the number and size of D-STATCOM. By comparing the net cost of D-STATCOM in relation to total system loss reduction single D-STATCOM installation has a better system. After the installation of single D-STATCOM with an optimal allocation through the feeder. The voltage profile of the system improved between 0.95-1.05p.u. The voltage stability index of the operated network increases as compared with base case stability. The active and reactive power loss through the line reduced to 25.03% and 25.25% respectively
Design and Analysis of Solar water pumping system for Agricultural Farming of Sweet Potato
(Mekelle University, 2025-04-07) Tsegabrhan Gebretsadkan
Quality of life, sustainable development, and economic progress are all largely influenced by energy. The shift to renewable energy sources has become essential in light of the growing global energy crisis, which is characterized by rising demands and the depletion of fossil fuel resources. Solar energy is one of the most promising of these, especially when it comes to solving important issues with agricultural methods.The design and study of a solar photovoltaic (PV) irrigation pumping system for sweet potato growing in the Abraha-Atsbeha hamlet are the focus of this thesis. Because they rely on expensive and environmentally damaging diesel pumping equipment, local farmers today confront many challenges. To address these challenges, the research begins with a comprehensive review of existing literature on solar irrigation technology, identifying key gaps and challenges in the field. Building on this foundation, a conceptual design for the PV irrigation system is developed, incorporating essential components such as the PV array, pump, storage tank, and control systems tailored to the specific needs of sweet potato cultivation. A detailed computer model of the proposed system is created and simulated using advanced software tools, including CROWAT, MATLAB, PSIM, HOMER, PVSyst, EasyEDA, and Drawing.io. Benchmarking exercises are conducted to evaluate the system's efficiency across varying climatic conditions by adjusting parameters like temperature and solar irradiance. The findings highlight the effectiveness of the Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) algorithm in optimizing power output and ensuring efficient operation. According to the results, the Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) algorithm is a good way to maximize power output and operational efficiency. In summary, a comparative study shows that the solar-powered irrigation system has several benefits over conventional diesel systems, such as decreased carbon emissions and operating expenses. The potential of solar technology to revolutionize farming methods, enhance food security, and support a sustainable energy emphasized by is this study
Reliability Enhancement of Distribution System by Using Feeder Reconfiguration (Case Study: Mekelle City Distribution System)
(Mekelle University, 2025-04-04) Meron Debru
Equipment failures and customer interruptions are the primary factors that affect distribution reliability. In many developing nations, including Ethiopia, reliability modeling and evaluation of distribution networks receive less attention "compared to" generating and transmitting systems. Since electric power is now used directly or indirectly for many of our activities, the utility should provide dependable electricity every day of the year to meet consumer demands and enable employees to do their jobs as efficiently as possible. However, several fault types affect the power supply’s reliability and quality. Power quality issues and interruptions are common in Mekelle distribution substation. Short-circuit faults, whether permanent or transient, system overloading and other factors are the primary causes of these interruptions. As a result, consumers are not receiving reliable power. The main goal of this work is the enhancement of the 15 kV side Mekelle distribution networks at a reasonable cost. Because several factors are causing power outages that mostly affect the 15 kV side. The reliability assessment has been done on fifteen feeders of the 15 kV Mekelle city distribution network. A reliability assessment of feeders on the 15 kV side has been carried out in order to assess the effectiveness of the current system and predict upcoming reliability evaluations. All the interruption data of five years (2011 E.C. up to 2015 E.C.) has been used which have been collected from Mekelle substation as well as north region Ethiopian electric power. Different alternatives have been assessed using ETAP 19.0.1 software method and the alternative with low SAIDI, SAIFI and EENS with a reasonable cost has been preferred. The reliability of Mekelle city distribution network has been enhanced significantly by implementing auto-reclosers that are justified economically. Even if the ambiguity of the input data is taken into account, SAIFI has been reduced by 59% as compared with the average reliability indices values of the existing system. In the similar way SAIDI and EENS have been decreased by 61% and 78.1% respectively.