1,721,078 research outputs found
Geomagnetically induced current sensitivity to assumed substation grounding resistances in the power system
Get PDFA geomagnetic disturbance (GMD) can result in severe damage to the power grid by inducing quasi-dc currents called geomagnetically induced current (GIC). Protection against GMD therefore necessitates the accurate estimation of GICs. GICs estimation is challenging because it depends on substation grounding resistances, which 1) depend more on the local soil and earth conditions than the construction of the substations themselves and 2) can vary by more than an order of magnitude, from 0.05 to 1.5 ohms. Substation grounding resistances are not contained in standard power system models, and approximate values are often used in GIC studies. This motivates the study in this thesis, which proposes a method to calculate the sensitivity of GIC at any substation due to both the substation being studied and neighboring substations’ grounding resistances. The work provides an algorithm to quantify the degree of dependence of the GICs at any given substation. The effectiveness of the method is illustrated using parameters from a real world power system. The case study results using the 20-bus GIC test system and a model of the North American Eastern Interconnect indicate that the substation GICs can be quite dependent on the assumed local substation grounding values. Subsequently, the same systems were studied to include neighboring substation grounding resistances. Although a few cases were dependent on the neighboring values, the local substation grounding resistances were more significant overall. These methods and results are further discussed and analyzed in this work.Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2018-12-01The student, Uyen Bui, accepted the attached license on 2016-12-04 at 13:22.The student, Uyen Bui, submitted this Thesis for approval on 2016-12-04 at 13:38.This Thesis was approved for publication on 2016-12-05 at 09:55.DSpace SAF Submission Ingestion Package generated from Vireo submission #10427 on 2017-02-28 at 14:37:16Made available in DSpace on 2017-03-01T16:37:06Z (GMT). No. of bitstreams: 2
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Previous issue date: 2016-12-05Embargo set by: Seth Robbins for item 98624
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Phasor measurement unit data visualizations and their role in improving operation of the electric grid
Get PDFMade available in DSpace on 2017-08-10T19:15:57Z (GMT). No. of bitstreams: 2
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Previous issue date: 2017-04-24In the energy industry, as in many other industries, data is growing faster than the tools needed to transform it into meaningful insights, decisions, and action. In the North American electric grid, many new sensors, called phasor measurement units, have been installed to better measure, assess, and provide situational awareness to operators of the electric grid. These devices can record measurements over 60 times more frequently than currents systems, meaning more data is available.
With the growth of electric grid data, much more work in the industry has focused on creating tools that can translate the wealth of phasor measurement unit data into improved operator system awareness and which can expedite and improve operator decision making. As such, this thesis documents the efforts of the University of Illinois to create visualizations of phasor measurement unit data for the purpose of improving operator situational awareness in electric grids. Specifically, the University of Illinois team created a large-scale electric grid model; created simulations, like earthquakes and ice storms, to strain the grid model; created a software tool that automates the process of going from simulation data to its analysis; and then created several data visualizations aimed at improving real time operation of the electric grid. Though the work was done for a specific region of the U.S. electric grid, the processes that were followed, the software that was built, and the visualizations that were made can be easily extended to any electric system, and, in fact, making sure they could be generalized was a key guiding principle of our work.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-08-10 without embargo termsThe student, Kathleen Gegner, accepted the attached license on 2017-04-21 at 15:38.The student, Kathleen Gegner, submitted this Thesis for approval on 2017-04-21 at 15:45.This Thesis was approved for publication on 2017-04-24 at 10:15.DSpace SAF Submission Ingestion Package generated from Vireo submission #10991 on 2017-08-10 at 13:45:3
Modeling the Electric Power Grid with Limited Information
No full textGrid operators typically have detailed information from only a few buses within their territory, and may not know the details of the system typography in their service territory. A model is presented here that estimates the reduced B-matrix of the system and is based solely on power and angle data from only a few buses within a larger network. The model can detect line outages and other disruptions by tracking the changes in the reduced B-matrix representation of the system. Its limited ability to locate said outages is also discussed.not peer reviewedSubmitted by Janice Progen ([email protected]) on 2014-01-17T19:18:01Z
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ECE499-Fa2010-spadoni.pdf: 259579 bytes, checksum: 2e1315c884760ca0bfa96b0c130f65ed (MD5)Approved for entry into archive by James Hutchinson([email protected]) on 2014-01-17T19:21:55Z (GMT) No. of bitstreams: 1
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Previous issue date: 2010-12Restriction data tranferred 2014-07-01T11:33:50-05:00
Original Data
Group with Access UIUC Users [automated]
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Reason: Undergraduate senior thesis not recommended for open accessItem marked as restricted to the 'UIUC Users [automated]' Group (id=2) by James Hutchinson ([email protected]) on 2014-01-17T19:21:55Z
Item is restricted indefinitely.Undergraduate senior thesis not recommended for open accessunpublishedU of I Onl
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The creation of synthetic power grids: preliminary considerations
Get PDFThis Thesis was approved for publication on 2016-11-21 at 09:16.This thesis presents preliminary considerations and an initial methodology for the systematic creation of synthetic power system test cases. The synthesized grids are built to match statistical characteristics found in actual power grids, but they do not correspond to any real grid and are thus free from confidentiality requirements. First, substations are geographically placed on a selected territory, synthesized from public information about the underlying population and generation plants. A clustering technique is employed, which ensures the synthetic substations meet realistic proportions of load and generation, among other constraints. Next, a network of transmission lines is added. This thesis describes several structural statistics to be used in characterizing real power system networks, including connectivity, Delaunay triangulation overlap, dc power flow analysis, and line intersection rate. The thesis presents a methodology to generate synthetic line topologies with realistic parameters which satisfy these criteria. Then, the test cases can be augmented with additional complexities to build large, realistic cases. An application to geomagnetic disturbance analysis is discussed as an example. The thesis illustrates the method with two example test cases, one with 150 buses and the other with 2000 buses. The methodology for creating each is shown, and the characteristics of these cases are validated against the observations from real cases.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2017-02-28 without embargo termsThe student, Adam Birchfield, accepted the attached license on 2016-11-18 at 10:51.The student, Adam Birchfield, submitted this Thesis for approval on 2016-11-18 at 11:03.DSpace SAF Submission Ingestion Package generated from Vireo submission #10269 on 2017-02-28 at 14:49:13Made available in DSpace on 2017-03-01T15:48:51Z (GMT). No. of bitstreams: 4
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Previous issue date: 2016-11-2
Automation tools for the verification and validation of transient stability models
Get PDFIn light of some major disturbances in the Western Interconnection over the past two decades, efforts are being made to improve the representation of the system to help prevent the underutilization or overutilization of the grid. Various transient stability software packages are widely used for dynamic analyses to help make key decisions in the planning, design, and operation of the power grid. Prior work and software documentation has shown that software packages implement the same dynamic models differently, which can lead to discrepancies in the simulation results of the same system. Dynamic models associated with the generator, such as the machine model, exciter, governor, and stabilizer, play a significant role in a system's dynamic response. However, in a large system, generator interface signals are affected by many other components of the system. To isolate the response of a generator, a single-machine infinite bus (SMIB) equivalent of a generator is created and its dynamic models are analyzed in detail to identify the source of the discrepancies. This research focuses on improving previous work by creating a graphical user interface (GUI) to automate the simulation and analysis of dynamic models in the SMIB generator equivalents.
Once discrepancies in the implementation of models between the software packages are addressed, the PowerWorld simulations are validated against phasor measurement unit (PMU) data collected during a disturbance. This research focuses on the beginning stages of this effort by creating a graphical user interface (GUI) to automate the formation of validation base cases by mapping generator dynamic models from planning cases to real-time cases.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2016-07-07 without embargo termsThe student, Beverly Raposa, accepted the attached license on 2016-04-21 at 14:10.The student, Beverly Raposa, submitted this Thesis for approval on 2016-04-21 at 14:24.This Thesis was approved for publication on 2016-04-26 at 09:32.DSpace SAF Submission Ingestion Package generated from Vireo submission #9414 on 2016-07-07 at 13:32:19Made available in DSpace on 2016-07-07T19:54:36Z (GMT). No. of bitstreams: 2
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Previous issue date: 2016-04-2
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Real-time validation of power system transient stability simulation results
Get PDFPerforming transient stability study using simulation software is crucial to determining the threshold amount of disturbance a system can handle before losing synchronism. These disturbances include events such as loss of generation, loss of a large load, or fault on transmission facilities. Currently, there are state estimator models used in simulating the transient stability response of large systems in the U.S. to disturbances.
This research project studies the transient stability models used in simulating a disturbance on the system, with a focus on generator modeling. The objective of this research project is to achieve a more optimized transmission grid, by facilitating better planning studies and operational enhancements. Real time state estimator cases do not have any generator or load models in them. A procedure has been developed to automatically load generator model data from the planning case into the real time case and troubleshoot the incorrect models to get the case ready for a transient stability run. With real-time PMU data, it will be possible to simulate the same contingency in commercial software, compare it with the recorded PMU data, and make modifications to the current model accordingly. In this work the preparation procedure will be discussed, as well as the comparison and interpretation of simulated and real-time data.Item withdrawn by Mark Zulauf ([email protected]) on 2014-12-04T16:12:24Z
Item was in collections:
University of Illinois Theses & Dissertations (ID: 1)
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Hughes_Yuchen.pdf: 1870358 bytes, checksum: 27951c47558f9766012821a4968efaa0 (MD5)Made available in DSpace on 2015-01-21T19:59:25Z (GMT). No. of bitstreams: 1
Yuchen_Hughes.pdf: 1870358 bytes, checksum: 27951c47558f9766012821a4968efaa0 (MD5)Embargo set by: Seth Robbins for item 73276
Lift date: 2017-01-21T19:59:39Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 73276 on 2017-01-22T10:15:20Z
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