DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING

Induction motors are the primary workhorses in industrial applications, but their starting phase poses significant challenges, namely high inrush currents and abrupt mechanical torque. This project presents a comparative study of Direct-On-Line (DOL), Star-Delta (Y-Δ), and Soft Starter methods for three-phase induction motors, with a specific focus on analyzing their transient performance using simulation. To conduct this analysis, dynamic models of an induction motor and the corresponding control circuits for each starter were developed and simulated using the MATLAB/SIMULINK environment. The study evaluates key performance metrics by comparing the simulation waveforms for stator current, rotor speed, and electromagnetic torque during the startup transient. The simulation results quantitatively demonstrate the severe inrush current (up to 6-8 times full load) and high-impact torque of the DOL starter. The Star-Delta simulation illustrates its effectiveness in reducing starting current to approximately 33% of DOL, but also clearly exposes the open-transition torque dip and current spike during the switchover. In contrast, the thyristor-based Soft Starter model demonstrates superior performance, offering a smooth, stepless acceleration, precise current-limiting capabilities, and the elimination of mechanical jerk. This simulation-based analysis provides a clear, quantitative framework for evaluating the trade-offs between cost, complexity, and performance, enabling engineers to select the most appropriate starter for specific load requirements and power system constraints

The project involved detailed load analysis, component selection, and system configuration. The final design ensures a stable power supply with provisions for future scalability. This work demonstrates the practical application of electrical/electronic engineering principles in solvingreal-world energy challenges and contributes toward the goal of sustainable development. In this project, the design of a 300kW stand-alone power system for the faculty of Engineering, implementation of a 10kW inverter/battery system for the Dean’s office, LT1, LT2, LT3, LT4 and the faculty board room was carried out.

This study aimed to assess the reliability of the OF 2x7.5MVA, 33kV/11kV Etete Injection Sub- Station, with a primary focus on understanding the historical performance and identifying key factors influencing its reliability. The objectives included conducting a comprehensive analysis of historical outage data, maintenance records, and operational parameters. Additionally, the study aimed to derive insights into the critical components and practices that affect substation reliability and develop recommendations for enhancing its pe formance. The research employed a multifaceted methodology, combining quantitative and qualitative approaches. Historical data, including outage records and maintenance logs, were meticulously collected and analyzed. Statistical tools, including reliability indices and time-series analysis, were employed to assess the substation's historical performance and outage patterns. Interviews with maintenance personnel and key stakeholders provided valuable qualitative insights. The study also considered external factors such as weather conditions and regulatory frameworks that influence substation reliability. Predictive modeling was used to extrapolate future scenarios, assessing the substation's ability to meet evolving demands. The study concludes that the reliability of the Etete Injection Substation varies based on observed variations in historical performance data. Over the past five years, the substation experienced an average of 9 outages annually, with an average outage duration of 3.5 hours. Outage frequencies exhibited a noticeable seasonal pattern, with an increase during the rainy season. Critical components, including transformers and circuit breakers, accounted for 70% of all outages. The overall reliability of the injection substation is 39.33% over the study period and this shows that the substation is not reliable. Furthermore, our predictive modeling revealed that withoutintervention, the substation may face a 20% increase in outages in the next three years

Induction motors are the primary workhorses in industrial applications, but their starting phase poses significant challenges, namely high inrush currents and abrupt mechanical torque. This project presents a comparative study of Direct-On-Line (DOL), Star-Delta (Y-Δ), and Soft Starter methods for three-phase induction motors, with a specific focus on analyzing their transient performance using simulation. To conduct this analysis, dynamic models of an induction motor and the corresponding control circuits for each starter were developed and simulated using the MATLAB/SIMULINK environment. The study evaluates key performance metrics by comparing the simulation waveforms for stator current, rotor speed, and electromagnetic torque during the startup transient. The simulation results quantitatively demonstrate the severe inrush current (up to 6-8 times full load) and high-impact torque of the DOL starter. The Star-Delta simulation illustrates its effectiveness in reducing starting current to approximately 33% of DOL, but also clearly exposes the open-transition torque dip and current spike during the switchover. In contrast, the thyristor-based Soft Starter model demonstrates superior performance, offering a smooth, stepless acceleration, precise current-limiting capabilities, and the elimination of mechanical jerk. This simulation-based analysis provides a clear, quantitative framework for evaluating the trade-offs between cost, complexity, and performance, enabling engineers to select the most appropriate starter for specific load requirements and power system constraints.