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- Genre: Academic theses
- Genre: Poetry
- Creators: Ayyanar, Raja
Description
At present, almost 70% of the electric energy in the United States is produced utilizing fossil fuels. Combustion of fossil fuels contributes CO2 to the atmosphere, potentially exacerbating the impact on global warming. To make the electric power system (EPS) more sustainable for the future, there has been an emphasis on scaling up generation of electric energy from wind and solar resources. These resources are renewable in nature and have pollution free operation. Various states in the US have set up different goals for achieving certain amount of electrical energy to be produced from renewable resources. The Southwestern region of the United States receives significant solar radiation throughout the year. High solar radiation makes concentrated solar power and solar PV the most suitable means of renewable energy production in this region. However, the majority of the projects that are presently being developed are either residential or utility owned solar PV plants. This research explores the impact of significant PV penetration on the steady state voltage profile of the electric power transmission system. This study also identifies the impact of PV penetration on the dynamic response of the transmission system such as rotor angle stability, frequency response and voltage response after a contingency. The light load case of spring 2010 and the peak load case of summer 2018 have been considered for analyzing the impact of PV. If the impact is found to be detrimental to the normal operation of the EPS, mitigation measures have been devised and presented in the thesis. Commercially available software tools/packages such as PSLF, PSS/E, DSA Tools have been used to analyze the power network and validate the results.
ContributorsPrakash, Nitin (Author) / Heydt, Gerald T. (Thesis advisor) / Vittal, Vijay (Thesis advisor) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2013
Description
Recent trends in the electric power industry have led to more attention to optimal operation of power transformers. In a deregulated environment, optimal operation means minimizing the maintenance and extending the life of this critical and costly equipment for the purpose of maximizing profits. Optimal utilization of a transformer can be achieved through the use of dynamic loading. A benefit of dynamic loading is that it allows better utilization of the transformer capacity, thus increasing the flexibility and reliability of the power system. This document presents the progress on a software application which can estimate the maximum time-varying loading capability of transformers. This information can be used to load devices closer to their limits without exceeding the manufacturer specified operating limits. The maximally efficient dynamic loading of transformers requires a model that can accurately predict both top-oil temperatures (TOTs) and hottest-spot temperatures (HSTs). In the previous work, two kinds of thermal TOT and HST models have been studied and used in the application: the IEEE TOT/HST models and the ASU TOT/HST models. And, several metrics have been applied to evaluate the model acceptability and determine the most appropriate models for using in the dynamic loading calculations. In this work, an investigation to improve the existing transformer thermal models performance is presented. Some factors that may affect the model performance such as improper fan status and the error caused by the poor performance of IEEE models are discussed. Additional methods to determine the reliability of transformer thermal models using metrics such as time constant and the model parameters are also provided. A new production grade application for real-time dynamic loading operating purpose is introduced. This application is developed by using an existing planning application, TTeMP, as a start point, which is designed for the dispatchers and load specialists. To overcome the limitations of TTeMP, the new application can perform dynamic loading under emergency conditions, such as loss-of transformer loading. It also has the capability to determine the emergency rating of the transformers for a real-time estimation.
ContributorsZhang, Ming (Author) / Tylavsky, Daniel J (Thesis advisor) / Ayyanar, Raja (Committee member) / Holbert, Keith E. (Committee member) / Arizona State University (Publisher)
Created2013
Description
Traditional approaches to modeling microgrids include the behavior of each inverter operating in a particular network configuration and at a particular operating point. Such models quickly become computationally intensive for large systems. Similarly, traditional approaches to control do not use advanced methodologies and suffer from poor performance and limited operating range. In this document a linear model is derived for an inverter connected to the Thevenin equivalent of a microgrid. This model is then compared to a nonlinear simulation model and analyzed using the open and closed loop systems in both the time and frequency domains. The modeling error is quantified with emphasis on its use for controller design purposes. Control design examples are given using a Glover McFarlane controller, gain sched- uled Glover McFarlane controller, and bumpless transfer controller which are compared to the standard droop control approach. These examples serve as a guide to illustrate the use of multi-variable modeling techniques in the context of robust controller design and show that gain scheduled MIMO control techniques can extend the operating range of a microgrid. A hardware implementation is used to compare constant gain droop controllers with Glover McFarlane controllers and shows a clear advantage of the Glover McFarlane approach.
ContributorsSteenis, Joel (Author) / Ayyanar, Raja (Thesis advisor) / Mittelmann, Hans (Committee member) / Tsakalis, Konstantinos (Committee member) / Tylavsky, Daniel (Committee member) / Arizona State University (Publisher)
Created2013
Description
Today, more and more substations are created and reconstructed to satisfy the growing electricity demands for both industry and residence. It is always a big concern that the designed substation must guarantee the safety of persons who are in the area of the substation. As a result, the safety metrics (touch voltage, step voltage and grounding resistance), which should be considered at worst case, are supposed to be under the allowable values. To improve the accuracy of calculating safety metrics, at first, it is necessary to have a relatively accurate soil model instead of uniform soil model. Hence, the two-layer soil model is employed in this thesis. The new approximate finite equations with soil parameters (upper-layer resistivity, lower-layer resistivity and upper-layer thickness) are used, which are developed based on traditional infinite expression. The weighted- least-squares regression with new bad data detection method (adaptive weighted function) is applied to fit the measurement data from the Wenner-method. At the end, a developed error analysis method is used to obtain the error (variance) of each parameter. Once the soil parameters are obtained, it is possible to use a developed complex images method to calculate the mutual (self) resistance, which is the induced voltage of a conductor/rod by unit current form another conductor/rod. The basis of the calculation is Green's function between two point current sources, thus, it can be expanded to either the functions between point and line current sources, or the functions between line and line current sources. Finally, the grounding system optimization is implemented with developed three-step optimization strategy using MATLAB solvers. The first step is using "fmincon" solver to optimize the cost function with differentiable constraint equations from IEEE standard. The result of the first step is set as the initial values to the second step, which is using "patternsearch" solver, thus, the non-differentiable and more accurate constraint calculation can be employed. The final step is a backup step using "ga" solver, which is more robust but lager time cost.
ContributorsWu, Xuan (Author) / Tylavsky, Daniel (Thesis advisor) / Undrill, John (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2013
Description
This thesis concerns the flashover issue of the substation insulators operating in a polluted environment. The outdoor insulation equipment used in the power delivery infrastructure encounter different types of pollutants due to varied environmental conditions. Various methods have been developed by manufacturers and researchers to mitigate the flashover problem. The application of Room Temperature Vulcanized (RTV) silicone rubber is one such favorable method as it can be applied over the already installed units. Field experience has already showed that the RTV silicone rubber coated insulators have a lower flashover probability than the uncoated insulators. The scope of this research is to quantify the improvement in the flashover performance. Artificial contamination tests were carried on station post insulators for assessing their performance. A factorial experiment design was used to model the flashover performance. The formulation included the severity of contamination and leakage distance of the insulator samples. Regression analysis was used to develop a mathematical model from the data obtained from the experiments. The main conclusion drawn from the study is that the RTV coated insulators withstood much higher levels of contamination even when the coating had lost its hydrophobicity. This improvement in flashover performance was found to be in the range of 20-40%. A much better flashover performance was observed when the coating recovered its hydrophobicity. It was also seen that the adhesion of coating was excellent even after many tests which involved substantial discharge activity.
ContributorsGholap, Vipul (Author) / Gorur, Ravi S (Thesis advisor) / Karady, George G. (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2013
Description
Chris Miller's Souvenirs of Sleep is as serious as it is whimsical, if this is a possibility. The "Museum of the Zoo-real" may be an equally appropriate title as animals are often in performance. In this visual and spiritual investigation, childhood, dream, and the loss of a mother to suicide are the currents. Miller's work is informed by the cinema of Werner Herzog, Andrei Tarkovsky, Robert Bresson and beyond. Miller believes in the power of implication. The poems begin with intense focus, but are often in the business of expansion. Souvenirs of Sleep is a journey toward sense-making, a search for language that might allow it.
ContributorsMiller, Christopher (Author) / Dubie, Norman (Thesis advisor) / Hogue, Cynthia (Committee member) / Ball, Sally (Committee member) / Arizona State University (Publisher)
Created2013
Description
A collection of poems that explore what it means to be from the Atomic City-- a city built atop cleared-out rural communities in East Tennessee during World War II, and with the sole and secretive purpose of enriching uranium for the atomic bomb. The poems look back to the more isolated Appalachian culture of previous generations, discovering the identity rifts caused by such massive and rushed development. In trying to understand the poet's own cultural inheritance of both nuclear weaponry and an Appalachian hardness, the poems begin to meditate on inhabitation. They ask what it means to live in a country, a local community, a body. The poems travel far beyond the Atomic City's limits, incorporating characters that live, in some sense, at the edge of a community. As he crosses the Atlantic, the Spanish poet Jiménez wonders if either sound or vision are more trustworthy tools for perception; an aging grandmother in Tennessee realizes that she still "drives" her younger body in her dreams; an American woman becomes aroused after touring the killing fields in Cambodia; and the prophet of Oak Ridge, who supposedly predicted the Manhattan Project, considers how his baby daughter has become a thing after death. The various voices show the poet grappling with her own guilt over Hiroshima, and ultimately attempt to understand the limits of both grief and love, how one inherits a tragedy.
ContributorsSams, Sara (Author) / Hogue, Cynthia (Thesis advisor) / Ball, Sally (Committee member) / Dubie, Norman (Committee member) / Arizona State University (Publisher)
Created2013
Description
Ranging in subject from a Tuareg festival outside Timbuktu to the 1975 "Battle of the Sexes" race at Belmont track to a Mississippi classroom in the Delta flood plains, the poems in The Body Snatcher's Complaint explore the blurring of self hood, a feeling of foreignness within one's own physical experience of the world, in the most intimate and global contexts.
ContributorsMurray, Catherine (Author) / Hogue, Cynthia (Thesis advisor) / Ball, Sally (Committee member) / Hummer, Terry (Committee member) / Arizona State University (Publisher)
Created2013
Description
Mapping Intersectionality in Harlem Renaissance Women's Poetry comprises the first book-length study devoted to examining the role women's poetry played in the Harlem Renaissance, an artistic and sociopolitical movement that reached its zenith in the 1920s. This study is situated in a theoretical interdisciplinarity that complicates critical approaches to Black women's subjectivities with respect to resistance and representation. It combines literary, race and gender theory to perform close readings of New Negro Women's poetry. Central chapters of the text theorize the poets' overshadowed engagement with the political movement via the tropes of interiority, motherhood, and sexuality; a closing chapter puts New Negro women's poetry in conversation with the Black Arts Movement. Building on the feminist sociological framework of Intersectionality, which considers the lived experience of individuals who embody multiple layers of marginalization, this dissertation works to identify and unpack sources of racialized gendered disparity in Harlem Renaissance studies. In acknowledging that self–actualization and self–articulation are central to this identity–based movement — a presupposition that informs this study's thesis — it becomes necessary to consider the gendered aspects of the writing for a more comprehensive review of the period. The analytical framework of Intersectionality provides a means to acknowledge New Negro women poets' perspectives regarding their racialized and gendered selves. In essence, Mapping Intersectionality is a concentrated effort toward unearthing evidence of their significant push against race and gender oppression. The motivation driving this study is revision and reclamation: revisionist in its concern for redefining the parameters in which the movement is traditionally perceived; a reclamation in its objective to underscore the influential, but nearly forgotten voices of the women poets of the Harlem Renaissance.
ContributorsPinkard, Michelle J., 1977- (Author) / Hogue, Cynthia (Thesis advisor) / Lester, Neal A. (Thesis advisor) / Reyes, Angelita (Committee member) / Arizona State University (Publisher)
Created2013
Description
As renewable energy becomes more prevalent in transmission and distribution systems, it is vital to understand the uncertainty and variability that accompany these resources. Microgrids have the potential to mitigate the effects of resource uncertainty. With the ability to exist in either an islanded mode or maintain connections with the main-grid, a microgrid can increase reliability, defer T&D; infrastructure and effectively utilize demand response. This study presents a co-optimization framework for a microgrid with solar photovoltaic generation, emergency generation, and transmission switching. Today unit commitment models ensure reliability with deterministic criteria, which are either insufficient to ensure reliability or can degrade economic efficiency for a microgrid that uses a large penetration of variable renewable resources. A stochastic mixed integer linear program for day-ahead unit commitment is proposed to account for uncertainty inherent in PV generation. The model incorporates the ability to trade energy and ancillary services with the main-grid, including the designation of firm and non-firm imports, which captures the ability to allow for reserve sharing between the two systems. In order to manage the computational complexities, a Benders' decomposition approach is utilized. The commitment schedule was validated with solar scenario analysis, i.e., Monte-Carlo simulations are conducted to test the proposed dispatch solution. For this test case, there were few deviations to power imports, 0.007% of solar was curtailed, no load shedding occurred in the main-grid, and 1.70% load shedding occurred in the microgrid.
ContributorsHytowitz, Robin Broder (Author) / Hedman, Kory W (Thesis advisor) / Heydt, Gerald T (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2013