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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.
1

Redesign for energy and reserve markets in electric power networks with high solar penetration

Hollis, Preston Taylor 07 September 2011 (has links)
Favorable price trends and increasing demand for renewable energy sources portend accelerating integration of solar photovoltaic (PV) generation into traditional electric power system networks. Managing the variable output of massive PV resources makes system frequency regulation more complex and expensive. ISOs must procure additional regulation and load following capacity, while power plants must supply more regulation work. In contrast to costly physical storage solutions, this thesis proposes to address the issue by reconfiguring the electricity market pricing structure to translate all power imbalances into real-time market price signals. More accurately determining the instantaneous value of energy, electric power markets could reward participants who can quickly respond to frequency fluctuations. By utilizing short term forward markets to monetize the risk associated with intermittency, the true cost of reliability is determined and could reduce wasteful capacity payments. This market redesign is an ideal open platform for disparate smart grid technologies which could encourage all suppliers, loads and generator, to offer supply or reduce consumption when it is needed most and could vastly improve frequency performance metrics.
2

Modeling and optimization of a thermosiphon for passive thermal management systems

Loeffler, Benjamin Haile 15 November 2012 (has links)
An optimally designed thermosiphon for power electronics cooling is developed. There exists a need for augmented grid assets to facilitate power routing and decrease line losses. Power converter augmented transformers (PCATs) are critically limited thermally. Conventional active cooling system pumps and fans will not meet the 30 year life and 99.9% reliability required for grid scale implementation. This approach seeks to develop a single-phase closed-loop thermosiphon to remove heat from power electronics at fluxes on the order of 10 - 15 W/cm2. The passive thermosiphon is inherently a coupled thermal-fluid system. A parametric model and multi-physics design optimization code will be constructed to simulate thermosiphon steady state performance. The model will utilize heat transfer and fluid dynamic correlations from literature. A particle swarm optimization technique will be implemented for its performance with discrete domain problems. Several thermosiphons will be constructed, instrumented, and tested to verify the model and reach an optimal design.
3

Dynamic control of grid power flow using controllable network transformers

Das, Debrup 19 December 2011 (has links)
The objective of the research is to develop a cost-effective, dynamic grid controller called the controllable network transformer (CNT) that can be implemented by augmenting existing load tap changing (LTC) transformers with an AC-AC converter. The concept is based on using a fractionally rated direct AC-AC converter to control the power through an existing passive LTC. By using a modulation strategy based on virtual quadrature sources (VQS), it is possible to control both the magnitude and the phase angle of the output voltage of the CNT without having any inter-phase connections. The CNT architecture has many advantages over existing power flow controllers, like absence of low frequency storage, fractional converter rating, retro-fitting existing assets and independent per-phase operation making it potentially attractive for utility applications. The independent control of the magnitude and the phase angle of the output voltage allow independent real and reactive power flow control through the CNT-controlled line. In a meshed network with asymmetric network stresses this functionality can be used to redirect power from critically loaded assets to other relatively under-utilized parallel paths. The power flow controllability of CNT can thus be used to lower the overall cost of generation of power. The solid state switches in the CNT with fast response capability enable incorporation of various additional critical functionalities like grid fault ride through, bypassing internal faults and dynamic damping. This bouquet of features makes the CNT useful under both steady state and transient conditions without compromising the grid reliability.
4

Aspects of autonomous demand response through frequency based control of domestic water heaters

Cooper, Douglas John January 2018 (has links)
A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering in the School of Electrical and Information Engineering, July 2017 / This dissertation presents the design and testing of controllers intended to provide au- tonomous demand response, through the use of water heater loads and grid frequency measurements. The controllers use measured frequency as an indication of the strain on a utility grid, which allows demand side management to be isolated from any form of central control. Water heaters can operate as exible loads because their power consump- tion can be dispatched or deferred without directly impacting users. These properties make it possible to control individual water heaters based on the functioning of the grid, rather than end user input. The purpose of this research is to ultimately provide a low- cost alternative to a traditional Smart Grid, that will improve the resilience of a grid without negatively impacting users. The controllers presented here focus on ensuring that users receive hot water, while attempting to reduce any imbalance between power generated and power consumed on the grid. Simulations of these controllers in various situations highlight that while the controllers developed respond suitably to variations in the grid frequency and adequately ensure end users receive hot water, the practical bene t of the controllers depends largely on the intrinsic characteristics of the grid. / CK2018
5

Impacts of automated residential energy management technology on primary energy source utilization

Roe, Curtis Aaron 08 November 2012 (has links)
The objective of the proposed research is to analyze automated residential energy management technology using primary energy source utilization. A residential energy management system (REMS) is an amalgamation of hardware and software that performs residential energy usage monitoring, planning, and control. Primary energy source utilization quantifies power system levels impacts on power generation cost, fuel utilization, and environmental air pollution; based on power system generating constraints and electric load. Automated residential energy management technology performance is quantified through a physically-based REMS simulation. This simulation includes individual appliance operation and accounts for consumer behavior by stochastically varying appliance usage and repeating multiple simulation iterations for each simulated scenario. The effect of the automated REMS under varying levels of control will be considered. Aggregate REMS power system impacts are quantified using primary energy source utilization. This analysis uses a probabilistic economic dispatch algorithm. The economic dispatch algorithm quantifies: fuel usage and subsequent environmental air pollution (EAP) generated; based on power system generating constraints and electric load (no transmission constraints are considered). The analysis will comprehensively explore multiple residential energy management options to achieve demand response. The physically-based REMS simulation will consider the following control options: programmable thermostat, direct load control, smart appliance scheduling, and smart appliance scheduling with a stationary battery. The ability to compare multiple automated residential energy management technology options on an equal basis will guide utility technology investment strategies.
6

Smart grid critical information infrastructure protection through multi-agency

Mavee, Sheu Menete Alexandre 30 June 2015 (has links)
M.Com. (Informatics) / Critical Infrastructure is the term used to describe assets that are of utmost importance, or in other words, essential in the functioning of an environment. Societies depend on their critical infrastructure in order to maintain and continuously improve on their population’s standard of living. The creation of more self-sustainable methods of energy consumption and generation drives towards the creation of a better and more efficient evolution of the power grid critical infrastructure, named the smart grid. The introduction of the smart grid brought in a paradigm shift towards the practices used to manage the generation and distribution of electric power. The introduction of highly capable information systems to intrinsically work with current power grid technologies provided the ability to enhance economic and environmental efficiency of power systems. Although providing a wide variety of benefits, such information systems also created new points of vulnerabilities, which if exploited, place the smart grid at risk of disruptions. In order to address the security issues that occur at the application and data exchange level of smart grid information systems, the dissertation proposed the use of a security model to protect the smart grid. The Multi-Agent Smart Grid Security (MA-SGS) model is based on the use of multiple autonomous intelligent software agents which attempt to create operational stability and efficiency in the smart grid...
7

Modeling and simulation of vehicle to grid communication using hybrid petri nets

Sener, Cansu 08 June 2015 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / With the rapid growth of technology, scientists are trying to find ways to make the world a more efficient and eco-friendly place. The research and development of electric vehicles suddenly boomed since natural resource are becoming very scarce. The significance of an electric vehicle goes beyond using free energy, it is environ- mental friendly. The objective of this thesis is to understand what Vehicle to Grid Communication (V2G) for an electric vehicle is, and to implement a model of this highly efficient system into a Hybrid Petri Net. This thesis proposes a Hybrid Petri net modeling of Vehicle to Grid (V2G) Communication topology. Initially, discrete, continuous, and hybrid Petri net's are defined, familiarized, and exemplified. Secondly, the Vehicle and Grid side of the V2G communication system is introduced in detail. The modeling of individual Petri nets, as well as their combination is discussed thoroughly. Thirdly, in order to prove these systems, simulation and programming is used to validate the theoretical studies. A Matlab embedded simulation program known as SimHPN is used to simulate specific scenario's in the system, which uses Depth-first Search (DFS) Algorithm. In addition to SimHPN simulation program, Matlab program is made to output four levels of the reachability tree as well as specifying duplicate and terminate nodes. This code incorporates a technique known as Breadth-first Search (BFS) Algorithm.

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