Browsing by Author "Mesut Baran, Committee Chair"

Now showing 1 - 5 of 5

Assessment of Stresses on Induction Motors Due to Momentary Service Interruptions
(2007-08-08) Cavaroc, John Peter Jr; Mesut Baran, Committee Chair; Arthur Kelley, Committee Co-Chair; Edward Grant, Committee Member; Gregory Buckner, Committee Member
This dissertation presents an assessment of the worst case stresses produced in an induction motor when the motor is allowed to ride through a power supply voltage disturbance. Results from laboratory experiments and computer simulations are shown. The experimental results are obtained from tests conducted on three squirrel cage induction motors, sized 10 hp, 50 hp, and 75 hp. Each motor is tested with three different load inertias, various motor loadings, and numerous interruption durations. The computer simulation results are obtained using a non-linear motor-load model, whose parameters are derived from a non-linear least squares parameter estimation technique. Experimental data acquired in the lab is used for the parameter estimation data and for the validation data. Deficiencies in the standard motor-load model are presented and addressed. Good agreement between the experimental data and the non-linear motor-load model data is achieved. Results show significant current and torque transients, but caused no significant damage to the motors or loads used for testing.
Control and Protection for Distribution Networks with Distributed Generators
(2004-09-15) El-Markabi, Ismail Mohamed Shaker; Michael Young, Committee Member; Mo-Yuen Chow, Committee Member; Mesut Baran, Committee Chair; Joel Trussell, Committee Member
The connection of distributed generators to distribution networks greatly influences the performance and stability of such networks. The purpose of the dissertation has been to investigate and attempt to resolve the impacts of connecting distributed generators to distribution networks. Two main problems were defined and studied, which are the effect of distributed generators on the feeder voltage regulation and on the feeder protection schemes. A central supervisory controller designed to regulate the feeder's voltage is presented, and the architecture of the controller is shown along with test results illustrating the ability of the controller to regulate the voltage along a feeder with distributed generators with minimum cost. In an attempt to regulate the feeder's voltage without the need for the feeder's explicit model, a multi-agent based distributed controller is proposed. The multi-agent system structure and design are illustrated, and test results comparing the performance of the two proposed controllers are shown. The dissertation then presents an approach to extend conventional fault analysis studies to include inverter interfaced distributed generators. Such an approach is essential for the proper selection and coordination of protective devices for a feeder with distributed generators. Finally, the dissertation illustrates the extent of deterioration a DG can cause on the overcurrent protective relay performance. An approach to solve this problem and restore the overcurrent relay performance is presented.
Control Methods for Energy Storage for Dispatching Intermittent Renewable Energy Sources
(2009-11-13) Teleke, Sercan; Johan Enslin, Committee Member; Mohan Putcha, Committee Member; Alex Huang, Committee Member; Mesut Baran, Committee Chair; Subhashish Bhattacharya, Committee Co-Chair
Solar, wind and other renewable energy sources are becoming an important part of energy supply to the power grid. Integrating a battery energy storage system (BESS) with a solar photovoltaic (PV) system or a wind farm can make these intermittent renewable energy sources more dispatchable. In this thesis, three different control methods for BESS are proposed for this purpose. For dispatching, the set point for the controllers is determined first using the historical data. Then using this reference, the power and energy ratings required for the BESS is calculated, and the battery operation in terms of charge/discharge duration is characterized. For optimal use of a BESS to minimize the deviations from dispatch set points, three control methods for BESS have been developed. The simulations have shown that the dispatch performance obtained with SOC feedback method is unsatisfactory compared to the other two methods namely optimal control and rule based control. The rule based control, and the optimal control performs very similar since the rule based control corresponds to the closed loop implementation of the optimal control. Moreover, the rule based method has several advantages over the optimal control such as less computation time, closed loop implementation, and no need for development of a mathematical model for BESS. In terms of BESS operation, it is seen that the BESS charge/discharge frequency is relatively high in this application; and hence, new type of batteries with high charge/discharge cycling rates are needed. Moreover, the control methods considered make a compromise in that they didnÃ¢â‚¬â„¢t utilize the BESS full capacity in order to extend the lifetime of the BESS, and hence, a large size BESS Ã¢â‚¬â€œ about 15%-25% of the solar PV/wind farm capacity Ã¢â‚¬â€œ is needed to have an effective hourly dispatch.
Power Supply, Protection, and Harmonic Analysis for an Electric Vehicle Charging System in a Large Parking Deck
(2010-02-17) Hutchinson, Shane Robert; Mesut Baran, Committee Chair; Srdjan Lukic, Committee Member; Wenye Wang, Committee Member
This thesis presents a power delivery architecture for an Electric Vehicle (EV) and Plug-in Hybrid Electric Vehicle (PHEV) charging system to be implemented in a parking deck for consumer use. The main design issues for this topic are covered, including the characterization of the PHEV and EV load using simulations, the layout of the power supply circuit, the sizing of cables and transformers, and electrical protection. The National Electrical code is used to size the equipment, following the guidelines of the IEEE Recommended Practice for Electric Power Systems in Commercial Buildings. The transformer is sized by a statistical analysis with the Monte Carlo method of the expected power by looking at the arrival times and initial states of charge of the vehicle batteries connected to the system. Included in this design is a current harmonic analysis of the HEV Toyota Prius with a Hymotion plug-in aftermarket kit and the Progress Energy Ford Escape PHEV. The NC State ATEC charger is also analyzed in software to get a comparison of the charger topologies. The harmonic current analysis and its effects on the transformer rating are discussed. The harmonic phase cancellation phenomenon is studied for the charging system, where current harmonics for multiple chargers connected to the same system are phase shifted from one another, resulting in a lesser value for the total distortion than the strict arithmetic sum of the harmonic current magnitudes. Final results are obtained by using the Monte Carlo method to apply a derating factor for the transformer in accordance with the IEEE C57.110 Standard.
Short Term Electric Load Forecasting.
(2010-09-10) Hong, Tao; Mesut Baran, Committee Chair; Simon Hsiang, Committee Chair; David Dickey, Committee Member; Shu Fang, Committee Member