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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
151

Modeling and Analysis of a Photovoltaic System with a Distributed Energy Storage System

Ma, Anthony Winston 01 May 2012 (has links)
As California continues to integrate more renewable energy into its electrical system, the state has experienced a corresponding rise in photovoltaic system installations. PV arrays are a unique source of power generation in that they are affected by the location of the sun, shading, and temperature changes. These characteristics make solar one of the most highly variable forms of renewable energy. In order to improve solar power’s consistency, PV systems require a supplemental source of power. The primary focus of this paper is to determine if distributed energy storage systems can be used to reduce the effect of solar intermittency. This paper examines the test data and system specifications of an experimental DESS. The benefits of using a DESS in a PV system are further studied using computer simulation modeling. This paper also shows through computer simulations how a maximum power point tracker can increase a PV array’s power output. The results of this thesis demonstrate that DESS’s are capable of smoothing out highly variable load profiles caused by intermittent solar power.
152

Adaptive remedial action schemes for transient instability

Zhang, Yi, January 2007 (has links) (PDF)
Thesis (Ph. D. electrical engineering)--Washington State University, December 2007. / Includes bibliographical references (p. 112-116).
153

Effects of ancillary service markets on frequency and voltage control performance of deregulated power systems

Roy, Jyotirmoy, January 2007 (has links) (PDF)
Thesis (M.S. in electrical engineering)--Washington State University, December 2007. / Includes bibliographical references (p. 57-58).
154

Severe accident analysis using dynamic accident progression event trees

Hakobyan, Aram P., January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 205-215).
155

Concept for Next Generation Phasor Measurement: A Low-Cost, Self-Contained, and Wireless Design

Miller, Brian Ray 01 December 2010 (has links)
Phasor measurement is a growth technology in the power grid industry. With new funding, grid reliability concerns, and power capacity margin motivating a smart grid transformation, phasor measurement and smart metering are taking center stage as the implementation methods for grid intelligence. This thesis proposes a novel concept for designing a next generation phasor measurement unit. The present generation phasor measurement unit relies upon venerable existing current and voltage transducer technology that is expensive, bulky, and not well suited to the modern age of digital and computerized control signals. Also, the rising proliferation of installed phasor measurement units will soon result in data overload and huge obligations for network bandwidth and processing centers. This brute-force approach is ill-advised. Forward thinking is required to foresee the future grid, its fundamental operation, and its sensor controller needs. A reasonably safe assumption is a future grid containing sensors numbering in the thousands or millions. This number of sensors cannot transmit raw data over the network without requiring enormous network capacity and data center processing power. This thesis proposes a novel concept—combining existing technologies such as improved current transducers and wireless precision time protocols to design a next generation phasor measurement unit. The unit is entirely self-contained. It requires no external connections due to inclusion of high performance transducers, processor, wireless radio, and even energy harvesting components. With easy, safe, and low cost installation, proliferation of thousands or millions of sensors becomes feasible. Also, with a scalable sensor network containing thousands or millions of parallel distributed processors, data reduction and processing within the network relieves the need for high bandwidth data transmission or supercomputing data centers.
156

Does purchasing power parity hold in developing countries? an application to the Asian countries /

Nuasir, Salah Ahmad. January 2001 (has links) (PDF)
Thesis (Ph.D.)--Wayne State University, 2001. / Adviser: Jay H. Levin. Includes bibliographical references.
157

Maximum power tracking control scheme for wind generator systems

Mena Lopez, Hugo Eduardo 10 October 2008 (has links)
The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor speed measurements as control variable inputs. The dependence on the accuracy of the measurement devices makes the controller less reliable. The proposed control scheme is based on the stiff system concept and provides a fast response and a dynamic solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier, a dc/dc boost converter, a current controlled voltage source inverter, and a microcontroller that commands the dc/dc converter to control the generator for maximum power extraction. The microcontroller will also be able to control the current output of the three-phase inverter. In this work, the aerodynamic characteristics of wind turbines and the power conversion system topology are explained. The maximum power tracking control algorithm with a variable step estimator is introduced and the modeling and simulation of the wind turbine generator system using the MATLAB/SIMULINK® software is presented and its results show, at least in principle, that the maximum power tracking algorithm developed is suitable for wind turbine generation systems.
158

Some optimization problems in power system reliability analysis

Jirutitijaroen, Panida 15 May 2009 (has links)
This dissertation aims to address two optimization problems involving power system reliabilty analysis, namely multi-area power system adequacy planning and transformer maintenance optimization. A new simulation method for power system reliability evaluation is proposed. The proposed method provides reliability indexes and distributions which can be used for risk assessment. Several solution methods for the planning problem are also proposed. The first method employs sensitivity analysis with Monte Carlo simulation. The procedure is simple yet effective and can be used as a guideline to quantify effectiveness of additional capacity. The second method applies scenario analysis with a state-space decomposition approach called global decomposition. The algorithm requires less memory usage and converges with fewer stages of decomposition. A system reliability equation is derived that leads to the development of the third method using dynamic programming. The main contribution of the third method is the approximation of reliability equation. The fourth method is the stochastic programming framework. This method offers modeling flexibility. The implementation of the solution techniques is presented and discussed. Finally, a probabilistic maintenance model of the transformer is proposed where mathematical equations relating maintenance practice and equipment lifetime and cost are derived. The closed-form expressions insightfully explain how the transformer parameters relate to reliability. This mathematical model facilitates an optimum, cost-effective maintenance scheme for the transformer.
159

Maximum power tracking control scheme for wind generator systems

Mena, Hugo Eduardo 15 May 2009 (has links)
The purpose of this work is to develop a maximum power tracking control strategy for variable speed wind turbine systems. Modern wind turbine control systems are slow, and they depend on the design parameters of the turbine and use wind and/or rotor speed measurements as control variable inputs. The dependence on the accuracy of the measurement devices makes the controller less reliable. The proposed control scheme is based on the stiff system concept and provides a fast response and a dynamic solution to the complicated aerodynamic system. This control scheme provides a response to the wind changes without the knowledge of wind speed and turbine parameters. The system consists of a permanent magnet synchronous machine (PMSM), a passive rectifier, a dc/dc boost converter, a current controlled voltage source inverter, and a microcontroller that commands the dc/dc converter to control the generator for maximum power extraction. The microcontroller will also be able to control the current output of the three-phase inverter. In this work, the aerodynamic characteristics of wind turbines and the power conversion system topology are explained. The maximum power tracking control algorithm with a variable step estimator is introduced and the modeling and simulation of the wind turbine generator system using the MATLAB/SIMULINK® software is presented and its results show, at least in principle, that the maximum power tracking algorithm developed is suitable for wind turbine generation systems.
160

Investigation of broadband over power line channel capacity of shipboard power system cables for ship communications networks

Akinnikawe, Ayorinde 15 May 2009 (has links)
Broadband over Power Line (BPL) technology has garnered significant attention lately due to recent advancements in solid state technologies and channel coding schemes. The successful application of BPL technology for in-home automation and networking has led to suggestions of applying BPL in other systems including ships. The application of BPL technology using the Shipboard Power System (SPS) as a potential communications network for ship automation systems has been proposed, to achieve recent U.S. Navy ship management concepts geared toward reducing ship manning while improving operational efficiency. This thesis presents an analytical model developed to examine the channel response characteristics and estimated throughput capacity of SPS cables. The work used a multiconductor transmission line theory based approach to model the channel response of SPS distribution lines and estimated the channel throughput capacity using a “water-filling” communication technique. This work found that BPL using the SPS holds a strong potential for use as a communications network for ship communication systems.

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