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Real-Time Contingency Analysis with Trans-mission Switching on Real Power System Data

Description

Transmission switching (TS) has shown to be an ef-fective power flow control tool. TS can reduce the system cost, improve system reliability, and enhance the management of in-termittent renewable resources.

Transmission switching (TS) has shown to be an ef-fective power flow control tool. TS can reduce the system cost, improve system reliability, and enhance the management of in-termittent renewable resources. This paper addresses the state of the art problem of TS by developing an AC-based real-time con-tingency analysis (RTCA) package with TS. The package is tested on real power system data, taken from energy management sys-tems of PJM, TVA, and ERCOT. The results show that post-contingency corrective switching is a ready to be implemented transformational technology that provides substantial reliability gains. The computational time and the performance of the devel-oped RTCA package, reported in the paper, are promising.

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Date Created
  • 2015-08

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Day-Ahead Corrective Adjustment of FACTS Reactance: A Linear Programming Approach

Description

Reserve requirements serve as a proxy for N-1 reli-ability in the security-constrained unit commitment (SCUC) problem. However, there is no guarantee that the reserve is deliv-erable for all scenarios (post-contingency

Reserve requirements serve as a proxy for N-1 reli-ability in the security-constrained unit commitment (SCUC) problem. However, there is no guarantee that the reserve is deliv-erable for all scenarios (post-contingency states). One cheap way to improve reserve deliverability is to harness the flexibility of the transmission network. Flexible AC transmission system (FACTS) devices are able to significantly improve the transfer capability. However, FACTS utilization is limited today due to the complexi-ties these devices introduce to the DC optimal power flow prob-lem (DCOPF). With a linear objective, the traditional DCOPF is a linear program (LP); when variable impedance based FACTS devices are taken into consideration, the problem becomes a non-linear program (NLP). A reformulation of the NLP to a mixed integer linear program, for day-ahead corrective operation of FACTS devices, is presented in this paper. Engineering insight is then introduced to further reduce the complexity to an LP. Alt-hough optimality is not guaranteed, the simulation studies on the IEEE 118-bus system show that the method finds the globally optimal solution in 98.8% of the cases. Even when the method did not find the optimal solution, it was able to converge to a near-optimal solution, which substantially improved the reliability, very quickly.

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Created

Date Created
  • 2015-09

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A Fast LP Approach for Enhanced Utilization of Variable Impedance Based FACTS Devices

Description

Transmission systems are under stress and need to be upgraded. Better utilization of the existing grid provides a fast and cheap alternative to building new transmission. One way to improve

Transmission systems are under stress and need to be upgraded. Better utilization of the existing grid provides a fast and cheap alternative to building new transmission. One way to improve the utilization of the transmission network is power flow control via flexible AC transmission system (FACTS) devices. While FACTS devices are used today, the utilization of these devices is limited; traditional dispatch models (e.g., security con-strained economic dispatch) assume a fixed, static transmission grid even though it is rather flexible. The primary barrier is the complexity that is added to the power flow problem. The mathe-matical representation of the DC optimal power flow, with the added modeling of FACTS devices, is a nonlinear program (NLP). This paper presents a method to convert this NLP into a mixed-integer linear program (MILP). The MILP is reformulat-ed as a two-stage linear program, which enforces the same sign for the voltage angle differences for the lines equipped with FACTS. While this approximation does not guarantee optimality, more than 98% of the presented empirical results, based on the IEEE 118 bus and Polish system, achieved global optimality. In the case of suboptimal solutions, the savings were still significant and the solution time was dramatically reduced.

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Created

Date Created
  • 2015-07

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Estimating Zonal Electricity Supply Curves in Transmission-Constrained Electricity Markets

Description

Many important electricity policy initiatives would directly affect the operation of electric power networks. This paper develops a method for estimating short-run zonal supply curves in transmission-constrained electricity markets that

Many important electricity policy initiatives would directly affect the operation of electric power networks. This paper develops a method for estimating short-run zonal supply curves in transmission-constrained electricity markets that can be implemented quickly by policy analysts with training in statistical methods and with publicly available data. Our model enables analysis of distributional impacts of policies affecting operation of electric power grid. The method uses fuel prices and zonal electric loads to determine piecewise supply curves, identifying zonal electricity price and marginal fuel. We illustrate our methodology by estimating zonal impacts of Pennsylvania's Act 129, an energy efficiency and conservation policy. For most utilities in Pennsylvania, Act 129 would reduce the influence of natural gas on electricity price formation and increase the influence of coal. The total resulted savings would be around 267 million dollars, 82 percent of which would be enjoyed by the customers in Pennsylvania. We also analyze the impacts of imposing a $35/ton tax on carbon dioxide emissions. Our results show that the policy would increase the average prices in PJM by 47–89 percent under different fuel price scenarios in the short run, and would lead to short-run interfuel substitution between natural gas and coal.

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Created

Date Created
  • 2015-02-01

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Communication, goals and collaboration in buyer-supplier joint product design

Description

Original equipment manufacturers (buyers) are increasingly involving suppliers in new product development as a means to increase efficiency and expand capabilities. To realize such benefits, however, the two firms need

Original equipment manufacturers (buyers) are increasingly involving suppliers in new product development as a means to increase efficiency and expand capabilities. To realize such benefits, however, the two firms need to have appropriate communication and goal structures to minimize friction while maximizing design quality. In addition, the effectiveness of the inter-firm interaction process, i.e. their collaboration quality, is also a key success factor. This study draws from Information Process Theory to propose that higher technical and relational uncertainty requires more inter-firm communication. The misalignment between communication intensity and uncertainty reduces both design quality and design efficiency. Goal incongruence, which always lowers project performance, is less harmful for projects with high technical uncertainty due to the potential of the conflict resolving process in improving decision quality and efficiency. Finally I use Hackman's theory of work group effectiveness to propose that collaboration quality fully mediates the effects of communication intensity and goal congruence on project outcomes. The study used an empirical survey of manufacturers as the primary method of data collection. Manufacturers that integrate and assemble complex and discrete products are the target population. Design engineers and project managers from manufacturers were my target respondents. Both SEM and hierarchical regression were used to test the conceptual model. The dissertation made five theoretical contributions. First, I introduced the concept that there is an optimal level of inter-firm communication intensity, exceeding which lowers design efficiency without improving design quality. Second, I theoretically defined and empirically operationalized two types of uncertainty, one on the project level and one on the inter-firm level, which were shown to moderate the effects of inter-firm communication and goal structures on collaboration outcomes. Third, this study examined the conditions when goal congruence is more effective in improving collaboration outcomes. Fourth, this study nominally and operationally defined collaboration quality, a theoretical construct which measure the effectiveness of inter-partner interactions rather than mere existence or amount of certain activities pursued by partners. Finally, I proposed several enhancements to existing construct measures.

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Created

Date Created
  • 2011

An orchestra audition handbook for bass players

Description

The following project is an audition preparation handbook for double bass players. The materials and techniques included are designed for use by advanced collegiate bass players seeking work as freelance

The following project is an audition preparation handbook for double bass players. The materials and techniques included are designed for use by advanced collegiate bass players seeking work as freelance or contracted musicians. Subjects ranging from finding an opening, becoming mentally and physically prepared, and developing the skills and experience necessary to be successful will be examined. The most frequently requested audition excerpts are included in this document, carefully extracted from the original orchestra parts and notated with efficient fingerings. Elements of style and performance are discussed. Each of the excerpts is recorded on the enclosed CD, performed by the author as examples to the readers. It is the hope of the author that the study and use of this text will better prepare the readers for entrance into the working world of the music industry. Ideas, processes, and materials that are often neglected in a degree program are examined with the hope that students will be better prepared to audition for, and win orchestral positions.

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Created

Date Created
  • 2011

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The acquisition of the subjunctive mood by intermediate-level learners of Spanish: the relationship between mood and modality

Description

This study examines the effect that the modality (volition, doubt, emotion, belief, knowledge, etc.) of matrix noun clauses has on the ability of intermediate (second-year) Spanish L2 students (n=56) to

This study examines the effect that the modality (volition, doubt, emotion, belief, knowledge, etc.) of matrix noun clauses has on the ability of intermediate (second-year) Spanish L2 students (n=56) to properly produce the subjunctive and indicative moods, the relative order in which students tend to most accurately produce the subjunctive in response to the modalities of volition, doubt, and emotion, and students' level of syntactic ability and mood development. Each participant took a test consisting of twenty questions containing various modalities intended to elicit either the subjunctive or indicative mood. Participants also filled out a questionnaire that was designed to ascertain the participants' level of formal and informal experience with Spanish. The results of this study show that a) when the subjunctive was the target response most participants favored the unmarked indicative mood significantly more than the marked subjunctive mood, b) students most accurately produced the subjunctive to the modality of volition (VL), followed by doubt (DT), and emotion (EM), which is consistent with Collentine's study, and c) students were able to process complex syntax when producing the unmarked indicative mood but not when they were prompted to produce the marked subjunctive mood. The results of this study show that pedagogical expectations regarding the acquisition of the subjunctive mood by second-year Spanish students may be unrealistic as these students were operating somewhere between the pre-syntactic and syntactic stages.

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Date Created
  • 2011

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The museum, the flâneur, and the book: the exhibitionary complex in the work of Henry James

Description

The Victorian era was the age of museum development in the United States. In the wake of these institutions, another important figure of the nineteenth century emerged--the flâneur. The flâneur

The Victorian era was the age of museum development in the United States. In the wake of these institutions, another important figure of the nineteenth century emerged--the flâneur. The flâneur represents the city, and provided new mechanisms of seeing to the public. The flâneur taught citizens how to gaze with a panoptic eye. The increasing importance of cultural institutions contributed to a new means of presenting power and interacting with the viewing public. Tony Bennett's exhibitionary complex theory, argues that nineteenth-century museums were institutions of power that educated, civilized, and through surveillance, encourage self-regulation of crowds. The flâneur's presence in the nineteenth century informed the public about modes of seeing and self-regulation--which in turn helped establish Bennett's theory inside the museum. The popular writing and literature of the time provides an opportunity to examine the extent of the exhibitionary complex and the flâneur. One of the most prominent nineteenth-century authors, Henry James, not only utilizes museums in his work, but he often uses them in just the manner Bennett puts forth in his theory. This is significant because the ideas about museums in James's work shaped the minds of an expanding literary public in the United States, and further educated, civilized, and regulated readers. James also represents the flâneur in his writing, which speaks to broader cultural implications of the both exhibitionary complex on the outside world, and the effects of broader cultural influences on the museum. Beyond the impact of James's work, in the late nineteenth century American culture increasingly became centered around the printed word. The central position of books in American culture at the end of the nineteenth century allowed books and libraries to appropriate the exhibitionary complex and become tools of power in their own right. The book and the library relate to the museum as part of a larger cultural environment, which emerged as a result of modernity and a response to the ever-changing nineteenth-century world.  

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Date Created
  • 2011

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Between reconciliation and justice: the struggles for justice and reconciliation in Colombia

Description

Over the past decades, Colombian society has endured the impact of a longstanding political conflict among different actors and outrageous expressions of violence, especially among left wing guerrillas, right wing

Over the past decades, Colombian society has endured the impact of a longstanding political conflict among different actors and outrageous expressions of violence, especially among left wing guerrillas, right wing paramilitary groups and the state government. Drawing on socio-legal studies in transitional justice and human rights, this research attempts to analyze the recent experience of transitional justice in Colombia. The main purpose of this research is to understand how political, institutional and social actors, especially the government, the courts, the human rights and transitional justice NGOs, and victims associations, frame the mechanisms of transitional justice and use legal instruments to transform the conflict and reach what they consider "justice." It also attempts to understand the relations between politics and law in the context of a hegemonic discourse of security and give account of the expressions of resistance of human rights networks. In doing so, this research advances theory on literature about law and society and transitional justice by means of applying and expanding the theoretical framework of socio-legal research via the process of transitional justice in Colombia. The dissertation presents information gathered in the field in Colombia between July 2009 and July 2010 through a qualitative research design based on document analysis and in-depth interviews with members of different international and domestic human rights organizations, victims' organizations and national institutions. The research explains how these organizations combined political and legal actions in order to contest a project of security, and more specifically a project of impunity that came from negotiations with the paramilitary groups. The research also explains how the human rights networks not only mobilized internationally to gain political support from the international community, but also how these organizations contributed to transform the political debate about victims' rights. The research also explains how the human rights organizations and victims' groups articulated the global discourse on human rights and the local and domestic meanings constructed by the emerging movements of victims. Finally, the research analyses the relevance of legal practices consisting on strategic use of law in order to protect the victims of human rights violations.

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Date Created
  • 2011

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A bilingual, bicultural interpreter and researcher navigates blurry boundaries and intersectionality

Description

A researcher reflects using a close reading of interview transcripts and description to share what happened while participating in multiple roles in a larger ethnographic study of the acculturation process

A researcher reflects using a close reading of interview transcripts and description to share what happened while participating in multiple roles in a larger ethnographic study of the acculturation process of deaf students in kindergarten classrooms in three countries. The course of this paper will focus on three instances that took place in Japan and America. The analysis of these examples will bring to light the concept of taking on multiple roles, including graduate research assistant, interpreter, cultural mediator, and sociolinguistic consultant within a research project serving to uncover challenging personal and professional dilemmas and crossing boundaries; the dual roles, interpreter and researcher being the primary focus. This analysis results in a brief look at a thought provoking, yet evolving task of the researcher/interpreter. Maintaining multiple roles in the study the researcher is able to potentially identify and contribute "hidden" knowledge that may have been overlooked by other members of the research team. Balancing these different roles become key implications when interpreting practice, ethical boundaries, and participant research at times the lines of separation are blurred.

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Date Created
  • 2011