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Sotomayor, Martínez Rodrigo. "System theoretic process analysis of electric power steering for automotive applications." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/105318.
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Thesis: S.M. in Engineering and Management, Massachusetts Institute of Technology, Engineering Systems Division, 2015.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (pages 101-103).<br>The automotive industry is constantly challenged with meeting and exceeding customer expectations while reducing time to market of new products in order to remain competitive. Providing new features and functionality into vehicles for customer satisfaction is becoming more challenging and driving design complexity to a higher level. Although traditional methods of Product Development Failure Mode identification such as FMEA (Failure Mode and Effect Analysis) or FTA (Fault Three Analysis) have been used to analyze failures in automotive systems, there are limitations when it comes to design errors, flawed requirements, human factors implications, and component interaction accidents in which all components operated as required but the system behavior was not as expected. In order to determine if there is room for improvement in current automotive product development process, this thesis applies Dr. Nancy Leveson's Systems-Theoretic Process Analysis (STPA) technique to compare and contrast with a Failure Modes and Effects Analysis (FMEA) approach as used in the automotive industry through a case study. A formal method of comparing results is proposed. This study found limitations with FMEA in terms of identifying unsafe interactions between systems, anticipating human error and other behaviors dependent on human interaction, identifying engineering design flaws, and producing requirements. STPA was able to find causes that had a direct relationship with those found in FMEA while also finding a portion of causes related to a higher level of abstraction of those in FMEA. STPA also found a subset of causes that FMEA was not able to find, which relate mainly to engineering design flaws and system interaction.<br>by Rodrigo Sotomayor Martínez.<br>S.M. in Engineering and Management
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Ahmad, M. Masood. "Sensitivity estimates via perturbation analysis in power system simulations." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15408.
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Troullinos, George. "Estimating order reduction for dynamic systems with applications to power system equivalents." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/13449.
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Parsi-Feraidoonian, Raiomand. "Application of catastrophe theory to transient stability analysis of multimachine power systems." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29723.
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Transient stability analysis is an important part of power planning and operation. For large power systems, such analysis is very time consuming and expensive. Therefore, an online
transient stability assessment will be required as these large power systems are operated close to their maximum limits. In this thesis swallowtail catastrophe is used to determine the transient stability regions. The bifurcation set represents the transient stability region in terms of power system transient parameters bounded by the transient stability limits. The system modelling is generalized in such, that the analysis could handle either one or any number of critical machines. This generalized model is then tested on a three-machine as well as a seven-machine system. The results of the stability analysis done with the generalized method is compared with the time solution and the results were satisfactory. The transient stability regions determined are valid for any changes in loading conditions and fault location. This method is a good candidate for on-line assessment of transient stability of power systems.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate
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Alexander, Richard. "Analysis of Aircraft Power Systems, Including System Modeling and Energy Optimization, with Predictions of Future Aircraft Development." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1523541008209354.
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Du, Zhaobin. "Area COI-based slow frequency dynamics modeling, analysis and emergency control for interconnected power systems." Click to view the E-thesis via HKUTO, 2008. http://sunzi.lib.hku.hk/hkuto/record/B4175783X.
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Schneider, Kevin Paul. "Analysis of critical infrastructure interactions /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5990.
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Parchure, Abhineet Himanshu. "Towards Three-Phase Dynamic Analysis of Large Electric Power Systems." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54574.
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This thesis primarily focuses on studying the impact of Distributed Generation (DG) on the electromechanical transients in the electric grid (distribution, transmission or combined transmission and distribution (TandD) systems) using a Three Phase Dynamics Analyzer (hereafter referred to as TPDA). TPDA includes dynamic models for electric machines, their controllers, and a three-phase model of the electric grid, and performs three-phase dynamic simulations without assuming a positive sequence network model. As a result, TPDA can be used for more accurate investigation of electromechanical transients in the electric grid in the presence of imbalances.
At present, the Electromagnetic Transient Program (EMTP) software can be used to perform three-phase dynamic simulations. This software models the differential equations of the entire electric network along with those of the machines. This calls for solving differential equations with time constants in the order of milliseconds (representing the fast electric network) in tandem with differential equations with time constants in the order of seconds (representing the slower electromechanical machines). This results in a stiff set of differential equations, making such an analysis extremely time consuming. For the purpose of electromechanical transient analysis, TPDA exploits the difference in the order of time constants and adopts phasor analysis of the electric network, solving differential equations only for the equipment whose dynamics are much slower than those of the electric network. Power Flow equations are solved using a graph trace analysis based approach which, along with the explicit partitioned method adopted in TPDA, can eventually lead to the use of distributed computing that will further enhance the speed of TPDA and perhaps enable it to perform dynamic simulation in real time .
In the work presented here, first an overview of the methodology behind TPDA is provided. A description of the object oriented implementation of TPDA in C++/C# is included. Subsequently, TPDA is shown to accurately simulate power system dynamics of balanced networks by comparing its results against those obtained using GE-PSLF®. This is followed by an analysis that demonstrates the advantages of using TPDA by highlighting the differences in results when the same problem is analyzed using a three-phase network model with unbalances and the positive sequence network model as used in GE-PSLF®. Finally, the impact of rapidly varying DG generation is analyzed, and it is shown that as the penetration level of DG increases, the current and voltage oscillations throughout the transmission network increase as well. Further, rotor speed deviations are shown to grow proportionally with increasing DG penetration.<br>Master of Science
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Fotuhi-Firuzabad, Mahmud. "Operating health analysis of electric power systems." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0012/NQ27407.pdf.
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Cheng, Carol Shaoyu. "A hybrid approach to power system voltage security assessment." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/15469.
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Gossman, Stephanie Mizzell. "A new proposed method of contingency ranking." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34667.
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Security analysis of a power system requires a process called contingency analysis that analyzes results from all possible single contingencies (i.e. outages) in the system. The process of contingency analysis requires the definition of a parameter that is used to monitor a certain aspect of the system, which is called a performance index. The performance index definitions used traditionally have been highly nonlinear, and the results have not accurately predicted the outcome of the performance index in some cases. These incorrect results are referred to as misrankings since the contingency results are usually placed in order of severity so that the most severe cases are evident.
This thesis considers a new definition of contingency ranking using a more linearized definition of the performance index. The construction of both the new, proposed definition and the classic definition both consider the current loading of circuits in the system as compared to their rated values. Specifically, the parameter measured by the proposed definition measures the difference, while the more nonlinear definition uses a ratio of the two quantities, which is then raised to a higher power.
A small, four bus test system is used to demonstrate the benefits of the new, more linearized definition. The average percent error for all single line contingencies of the system decreased by over 9.5% using the proposed definition as compared to the previous one. This decrease in error allows this performance index to monitor a similar parameter (comparing current loading and current rating of the lines) and achieve a higher degree of accuracy. Further linearization of this proposed definition also shows a reduction in the average percent error by an additional 22% so that when compared to the original, highly nonlinear definition, the average error is reduced by almost 30%. By linearizing the definition of the performance index, the results are more accurate and misrankings are less likely to occur from the security analysis process.
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Maitra, Arindam. "A generic approach to network modeling for harmonic analysis." Diss., Mississippi State : Mississippi State University, 2002. http://library.msstate.edu/etd/show.asp?etd=etd-03272002-133910.
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Setréus, Johan. "On Reliability Methods Quantifying Risks to Transfer Capability in Electric Power Transmission Systems." Licentiate thesis, KTH, Electromagnetic Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10258.
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<p><p>In the operation, planning and design of the transmission system it is of greatest concern to quantify the reliability security margin to unwanted conditions. The deterministic N-1 criterion has traditionally provided this security margin to reduce the consequences of severe conditions such as widespread blackouts. However, a deterministic criterion does not include the likelihood of different outage events. Moreover, experience from blackouts shows, e.g. in Sweden-Denmark September 2003, that the outages were not captured by the N-1 criterion. The question addressed in this thesis is how this system security margin can be quantified with probabilistic methods. A quantitative measure provides one valuable input to the decision-making process of selecting e.g. system expansions alternatives and maintenance actions in the planning and design phases. It is also beneficial for the operators in the control room to assess the associated security margin of existing and future network conditions.</p><p>This thesis presents a method that assesses each component's risk to an insufficient transfer capability in the transmission system. This shows on each component's importance to the system security margin. It provides a systematic analysis and ranking of outage events' risk of overloading critical transfer sections (CTS) in the system. The severity of each critical event is quantified in a risk index based on the likelihood of the event and the consequence of the section's transmission capacity. This enables a comparison of the risk of a frequent outage event with small CTS consequences, with a rare event with large consequences.</p><p>The developed approach has been applied for the generally known Roy Billinton Test System (RBTS). The result shows that the ranking of the components is highly dependent on the substation modelling and the studied system load level.</p><p>With the restriction of only evaluating the risks to the transfer capability in a few CTSs, the method provides a quantitative ranking of the potential risks to the system security margin at different load levels. Consequently, the developed reliability based approach provides information which could improve the deterministic criterion for transmission system planning.</p></p>
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Khan, Atif Zaman. "Eigenvalue sensitivites and their applications to power system voltage stability." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/13911.
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McDonald, John D. F. "Investigations into the design of Powerformer for optimal generator and system performance under fault conditions /." [St. Lucia, Qld], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe18316.pdf.
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Tong, Shiqiong Miu Karen Nan. "Slack bus modeling for distributed generation and its impacts on distribution system analysis, operation and planning /." Philadelphia, Pa. : Drexel University, 2006. http://hdl.handle.net/1860/1229.
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Stefopoulos, Georgios Konstantinos. "Quadratic power system modeling and simulation with application to voltage recovery and optimal allocation of VAr support." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29695.
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Thesis (Ph.D)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010.<br>Committee Chair: Meliopoulos, A. P. Sakis; Committee Member: Deng, Shijie; Committee Member: Divan, Deepakraj; Committee Member: Harley, Ronald; Committee Member: Taylor, David. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Yu, Chang. "An investigation of subsynchronous oscillation of AC/DC power systems modeling and analysis /." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B37151885.
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Whitcomb, Clifford Alan. "Composite system analysis of advanced shipboard electrical power distribution systems." Thesis, Cambridge, Massachusetts : Massachusetts Institute of Technology, 1992. http://handle.dtic.mil/100.2/ADA254851.
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Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1992 and Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1992.<br>Thesis Advisor: Kirtley, James L., Jr. "May 1992." Description based on title screen as viewed on March 30, 2009. Includes bibliographical references (p. 73-74). Also available in print.
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Du, Zhaobin, and 杜兆斌. "Area COI-based slow frequency dynamics modeling, analysis and emergency control for interconnected power systems." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2008. http://hub.hku.hk/bib/B4175783X.
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Kumbale, Murali. "Bulk transmission system reliability analysis of protection and control groups." Thesis, Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/13840.
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Hasanović, Amer. "A simulation and analysis toolbox for power systems and genetic algorithm based damping controller design." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=2173.
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Thesis (M.S.)--West Virginia University, 2001.<br>Title from document title page. Document formatted into pages; contains viii, 73 p. : ill. Includes abstract. Includes bibliographical references (p. 71-73).
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Miao, Hanjin. "Intelligent system methods for energy management system and sequence-of-events recorder information analysis /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/6133.
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Cho, Bo Hyung. "Modeling and analysis of spacecraft power systems." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/54741.
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A comprehensive large-scale power system modeling is developed to facilitate the design and analysis of present and future spacecraft power systems. A two-port coupling method is utilized to provide a modularity in model building and analysis of the system. The modular approach allows the model to be flexible, verifiable and computationally efficient. A methodology for the system level analysis is presented with the ability to focus on the performance characteristics of an arbitrary component or subsystem. The system performance parameters are derived explicitly in terms of the two-port hybrid g-parameter representation of the component or subsystem, and impedances of its terminating subsystems. From this, the stability of the system is analytically determined and the subsystem interaction criteria is observed. Also presented is a model development from the empirical data employing the complex curve fitting technique. The technique is especially powerful for large scale system modeling and analysis where certain components and subsystems are viewed as black boxes with measurable terminal characteristics. The technique can also be used to realize a reduced order model of a complex subsystem.
The Direct Energy Transfer (DET) spacecraft power system is modeled to demonstrate the versatility of the comprehensive system model by performing various DC, small-signal and large-signal analyses. Of particular interest is the analysis of the large-signal behavior of the nonlinear solar array system by employing the state-plane method. The analysis of the solar array system operation focused on the transition mode between the shunt mode and the battery discharging mode is presented. The subsystem interaction problems in the local component and global system are illustrated. A methodology for the design and trouble-shooting of a system dealing with the interaction problems using the g-parameters is described. Finally, a system level analysis of the DET system using an empirical data modeling technique is performed.<br>Ph. D.
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Ajitkumar, Rohit. "An analysis of DC distribution systems." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39590.
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The Master's Thesis research focuses on analyzing the possibilities of using Direct Current distribution systems to distribute power to end users. Considering the shift in load types in the past few decades and also a growing demand of distributed generation, DC distribution can potentially offer higher efficiencies and cost savings to utilities. The incorporation of DC distribution offers the opportunity to eliminate multiple conversion stages for devices which are powered using DC electricity. The integration of power sources such as photovoltaics and fuel cells, which produce DC power, offer further incentives to consider the use of DC systems. Using DC systems can help eliminate the conversion losses associated with rectifiers and inverters which would be part of the infrastructure if AC distribution was used. In the literature, the study of DC distribution has been limited to customized systems. The objective of this research is to analyze DC distribution when applied to systems based on standard IEEE test feeder systems. The IEEE 13 node test feeder and the IEEE 37 node test feeder will be used as the basis for the analysis. Issues such as associated costs, protection and integration of appliances will also be addressed.
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Gursoy, Ekrem Niebur Dagmar. "Independent component analysis for harmonic source identification in electric power systems /." Philadelphia, Pa. : Drexel University, 2007. http://hdl.handle.net/1860/1781.
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Begovic, Miroslav M. "Analysis, monitoring and control of voltage stability in electric power systems." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54490.
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The work presented in this text concentrates on three aspects of voltage stability studies: analysis and determination of suitable proximity indicators, design of an effective real-time monitoring system, and determination of appropriate emergency control techniques. A simulation model of voltage collapse was built as analytical tool on 39-bus, 10-generator power system model. Voltage collapse was modeled as a saddle-node bifurcation of the system dynamic model reached by increasing the system loading. Suitable indicators for real-time monitoring were found to be the minimum singular value of power flow Jacobian matrix and generated reactive powers. A study of possibilities for reducing the number of measurements of voltage phasors needed for voltage stability monitoring was also made. The idea of load bus coherency with respect to voltage dynamics was introduced. An algorithm was presented which determines the coherent clusters of load buses in a power system based on an arbitrary criterion function, and the analysis completed with two proposed coherency criteria. Very good agreement was obtained by simulation between the results based on accurate and approximate measurements of the state vector. An algorithm was presented for identification of critical sets of loads in a voltage unstable power system, defined as a subset of loads whose changes have the most pronounced effect on the changes of minimum singular value of load flow Jacobian or generated reactive powers. Effects of load shedding of critical loads were investigated by simulation and favorable results obtained. An investigation was also done by sensitivity analysis of proximity indicators of the effects that locations and amounts of static var compensation have on the stability margin of the system. Static compensation was found to be of limited help when voltage instabilities due to heavy system loading occur in power systems. The feasibility of implementation of the analyses and algorithms presented in this text relies on development of a feasible integrated monitoring and control hardware. The phasor measurement system which was designed at Virginia Polytechnic institute and State University represents an excellent candidate for implementation of real-time monitoring and control procedures.<br>Ph. D.
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Parnandi, Silpa. "Power market analysis tool for congestion management." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5187.
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Thesis (M.S.)--West Virginia University, 2007.<br>Title from document title page. Document formatted into pages; contains viii, 71 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 68-71).
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Johan, Fredrik Raak. "Data-driven analysis of wind power and power system dynamics via Koopman mode decompositioｎ". Kyoto University, 2017. http://hdl.handle.net/2433/227628.
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Christoforidis, George P. "Harmonic analysis of power systems connected to converter substations." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/14994.
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Leedy, Aleck Wayne Nelms R. M. "Analysis of DC power systems containing induction motor-drive loads." Auburn, Ala., 2006. http://repo.lib.auburn.edu/2006%20Spring/doctoral/LEEDY_ALECK_32.pdf.
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Cvetkovic, Igor. "Modeling, Analysis and Design of Renewable Energy Nanogrid Systems." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/34994.
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The thesis addresses electronic power distribution systems for the residential applications. Presented are both, renewable energy ac-nanogrid system along with the vehicle-to-grid technology implementation, and envisioned structure and operation of dc-nanogrid addressing all system components chosen as an inherent part of the future electrical architecture. The large-scale model is built and tested in the laboratory environment covering a few operational modes of the ac-nanogrid, while later in the thesis is shown how dc bus signaling technique could be contemplated for the energy management of the renewable energy sources and their maximal utilization.
Thesis however puts more focus on the dc-nanogrid system to explore its benefits and advantages for the electrical systems of the future homes that can easily impact not only residential, but also microgrid, grid and intergrid levels. Thus, presented is low frequency terminal behavioral modeling of the system components in dc-nanogrid motivated by the fact that system engineers working on the system-level design rarely have access to all the information required to model converters and system components, other than specification and data given in the datasheets. Using terminal behavioral modeling, converters are measured on-line and their low frequency dynamics is identified by the means of the four transfer functions characteristically used in two port network models. This approach could significantly improve system-level design and simulations.
In addition to previously mentioned, thesis addresses terminal behavioral modeling of dc-dc converters with non-linear static behavior showing hybrid behavioral models based on the Hammerstein approach.<br>Master of Science
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Huynh, Phuong. "Stability analysis of large-scale power electronics systems." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40205.
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A new methodology is proposed to investigate the large-signal stability of interconnected power electronics systems. The approach consists of decoupling the system into a source subsystem and a load subsystem, and stability of the entire system can be analyzed based on investigating the feedback loop formed by the interconnected source/load system. The proposed methodology requires two stages: (1) since the source and the load are unknown nonlinear subsystems, system identification, which consists of isolating each subsystem into a series combination of a linear part and a nonlinear part, must be performed, and (2) stability analysis of the interconnected system is conducted thereafter based on a developed stability criterion suitable for the nonlinear interconnected-block-structure model. Applicability of the methodology is verified through stability analysis of PWM converters and a typical power electronics system.<br>Ph. D.
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Mthunzi, Everett Mondliwethu. "Performance analysis of a protection scheme based on P-class synchrophasor measurements." Thesis, Cape Peninsula University of Technology, 2016. http://hdl.handle.net/20.500.11838/2378.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2016.<br>Power grid and system protection advancement greatly depend on technological advances. Advent technologies like digital microprocessor type protective relays facilitate paradigm shifts, providing inimitable beneficial engineering adaptations. Phasor measuring technology provides one such technological advance. The onset and rapid development of the Phasor Measuring Unit (PMU) provides an excellent platform for phasor-based, power system engineering.
Power transmission constitutes a critical section in the electric power system. The power system transmission lines are susceptible to faults which require instant isolation to establish and maintain consistent system stability. This research focuses on the study of transmission line protection based on P-Class synchrophasor measurements. The IEEE C37.238-2011 Precision Time Protocol (PTP) paradigm shift facilitates practical application of synchrophasors in protection schemes. Synchrophasor procession and accurate data alignment over wide areas support the hypothesis of a phasor-based transmission line differential protection. This research aims to directly implement P-Class synchrophasors in transmission line differential protection, employing synchrophasors to determine fault conditions and administer corresponding protective actions in wide area transmission lines. The research also aims to evaluate the operational characteristics of the synchrophasor-based transmission line differential protection scheme.
The research deliverables include a laboratory scale Test-bench that implements the PMU-based transmission line differential protection scheme, and a differential protection utility software solution that follows guidelines specified by the C37.118-2011 standard for synchrophasors.
The findings stand to evaluate performance of the PMU-based line differential protection scheme, verifying the protection model as an alternate, practical and feasible backup protection solution. The research deliverables include a synchrophasor-based current differential algorithm, software utility for implementing the PMU-based protection scheme and a Test-bench for concept and feasibility validation.
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Khaniya, Dina. "Development of three-phase continuation power flow for voltage stability analysis of distribution systems." Master's thesis, Mississippi State : Mississippi State University, 2008. http://library.msstate.edu/etd/show.asp?etd=etd-11142008-101009.
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Hjartarson, Thorhallur. "Application of catastrophe theory to voltage stability analysis of power systems." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29623.
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In this thesis catastrophe theory is applied to the voltage stability problem in power systems. A general model for predicting voltage stability from the system conditions is presented and then applied to both a simple 2-bus explanatory power system and to a larger more realistic power system.
The model is based on the swallowtail catastrophe which with its three control variables is able to determine the voltage stability of the system. The model is derived directly from the systems equations. The voltage stability of the system at each specified system bus is determined by comparing the values of the swallowtail catastrophe control variables with those of the unique region of voltage stability. The control variables are calculated from the system operating conditions. If the control variables specify a point inside the stability region, the system is voltage stable; otherwise it is voltage unstable.<br>Applied Science, Faculty of<br>Electrical and Computer Engineering, Department of<br>Graduate
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Mazumdar, Joy. "System and method for determining harmonic contributions from nonlinear loads in power systems." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/23215.
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The objective of this research is to introduce a neural network based solution for the problem of measuring the actual amount of harmonic current injected into a power network by an individual nonlinear load. Harmonic currents from nonlinear loads propagate through the system and cause harmonic pollution. As a result, voltage at the point of common coupling (PCC) is rarely sinusoidal. The IEEE 519 harmonic standard provides customer and utility harmonic limits and many utilities are now requiring their customers to comply with IEEE 519. Measurements of the customer’s current at the PCC are expected to determine the customer’s compliance with IEEE 519. However, results in this research show that the current measurements at the PCC are not always reliable in that determination. In such a case, it may be necessary to determine what the customer’s true current harmonic distortions would be if the PCC voltage could be a pure sinusoidal voltage. However, establishing a pure sinusoidal voltage at the PCC may not be feasible since that would mean performing utility switching to reduce the system impedance. An alternative approach is to use a neural network that is able to learn the customer’s load admittance. Then, it is possible to predict the customer’s true current harmonic distortions based on mathematically applying a pure sinusoidal voltage to the learned load admittance. The proposed method is called load modeling. Load modeling predicts the true harmonic current that can be attributed to a customer regardless of whether a resonant condition exists on the utility power system. If a corrective action is taken by the customer, another important parameter of interest is the change in the voltage distortion level at the PCC due to the corrective action of the customer. This issue is also addressed by using the dual of the load modeling method. Topologies of the neural networks used in this research include multilayer perceptron neural networks and recurrent neural networks. The theory and implementation of a new neural network topology known as an Echo State Networks is also introduced. The proposed methods are verified on a number of different power electronic test circuits as well as field data. The main advantages of the proposed methods are that only waveforms of voltages and currents are required for their operation and they are applicable to both single and three phase systems. The proposed methods can be integrated into any existing power quality instrument or can be fabricated into a commercial standalone instrument that could be installed in substations of large customer loads, or used as a hand-held clip on instrument.
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Smith, Philip Hartley. "Electrical Distribution Modeling:An Integration of Engineering Analysis and Geographic Information Systems." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/36158.
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This thesis demonstrates the value of integrating electrical distribution engineering analysis with Geographic Information Systems (GIS). The 37-Node IEEE Feeder model was used as the base distribution system in this study. It was modeled separately, both in software capable of unbalanced load-flow and in an industry-standard GIS environment. Both tools utilized were commercially available, off-the shelf products indicative of those used in academia and in basic GIS installations. The foundational data necessary to build these models is representative of information required by a variety of utility departments for a multitude of applications. It is inherent to most systems within an enterprise-level, business-wide data model and therefore can be used to support a variety of applications. In this instance, infrastructure information is assumed to be managed and housed with the GIS. This data provides the required information as input for load-flow calculations. The engineering analysis is performed within DistributionSystem 4.01 and its output is passed back to the GIS in tabular format for incorporation. This thesis investigates the transfer of information between GIS and DistributionSystem 4.01 and demonstrates the extended display capabilities in the GIS environment. This research is implemented on a small scale, but is intended to highlight the need for standardization and automatic integration of these systems as well as others that are fundamental to the effective management of electrical distribution systems.<br>Master of Science
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Fourie, Gert. "Power system stabilizer and controlled series capacitor small-signal stability performance analysis." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/53013.
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Thesis (MScEng)--University of Stellenbosch, 2002.<br>ENGLISH ABSTRACT: This thesis presents results of a study on the small-signal stability of a single-machine
infinite-bus power system. Conditions of generator loading and network impedance are
identified that require additional stability support. Two methods of stability enhancement are
investigated, namely the power system stabilizer and the controlled series capacitor. Both
stabilizers employ the conventional (classic) control structure, and parameters are evaluated
for optimum performance using an integral-of-the-squared-error-based method. Results for
damping capability versus generator loading and system impedance were generated. The
ability of the power system stabilizer and controlled series capacitor to provide stability
support is compared. This comparison is based on (a) the ability to provide more damping
torque when needed, and (b) the amount of damping torque contributed by the stabilizer.<br>AFRIKAANSE OPSOMMING: Hierin word die resultate van 'n studie op die klein-sein stabiliteit van 'n enkel-masjien
oneindige-bus kragstelsel weergegee. Kondisies van generator belasting en netwerk
impedansie waar dempings-ondersteuning benodig word, word geïdentifiseer. Twee metodes
van stabiliteits-verbetering word ondersoek, naamlik die kragstelstel stabiliseerder en die
beheerde serie kapasitor. Beide stabiliseerders maak gebruik van die konvensionele
(klassieke) beheerstruktuur, waarvan parameters geëvalueer word deur gebruik te maak van
'n integraal-van-die-vierkant-fout-gebaseerde metode. Resultate vir dempingsvermoë
teenoor generator belasting en stelsel impedansie word verkry. Die vermoë van die
kragstelsel stabiliseerder en beheerde serie kapasitor om stabiliteits-ondersteuning te verskaf,
word vergelyk. Hierdie vergelyking is gebasseer op (a) die vermoë om meer
dempingswrinkrag te voorsien wanneer benodig, en (b) die hoeveelheid dempingswrinkrag
deur die stabiliseerder bygedra.
40
Yu, Chang, and 余暢. "An investigation of subsynchronous oscillation of AC/DC power systems: modeling and analysis." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B37151885.
Full text
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Tweedy, Phillip. "Analysis of Hybrid Electric Autonomous Tactical Support System." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76877.
Full textAbstract:
The modern day expeditionary warfighter faces extraordinary challenges in the battle field and being a beast of burden should not be one of them. Currently the dismounted warfighter is impeded with carrying over 100lbs of tactical gear and supplies for multiday missions in remote territory. Expeditionary forces are also facing an energy and logistical crisis getting water, fuel, and batteries to the tip of the spear. Finding ways to enable self-sufficiency and reducing resupply tethers for small unit operations is a high priority for the armed forces. The Hybrid Electric Autonomous Tactical Support System directly and efficiently tackles both problems head on by synergizing efforts to lighten the load and self sustaining base power by combining the capabilities of the Ground Unmanned Support Surrogate (GUSS) and the Experimental Forward Operating Base projects. Hybridization of the drivetrain of the GUSS vehicle will provide the reliable power for onboard autonomous systems and also enable silent operation modes. The hybrid onboard generator can efficiently provide generous amounts of exportable DC and AC power on demand and is an ideally sized backup/primary power system for small unit bases and forward command posts. The vehicle's onboard energy storage and generator system can also be linked with renewable energy sources to demonstrate the tactical smart mini grid concept. This thesis develops the power requirements for an autonomous system, GUSS mission derived hybrid electric drivetrain specifications, and Marine Corps small echelon bases for the development of the multifunction Hybrid Electric Autonomous Tactical Support System.<br>Master of Science
42
Hansen, Charles William. "Model enhancements for state estimation in electric power systems." Diss., Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/15611.
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Chan, Yau Chung John. "A novel electric power quality monitoring system for transient analysis." Thesis, City University London, 2014. http://openaccess.city.ac.uk/5911/.
Full textAbstract:
Electricity is vital for our daily life in modern cites. In order to ensure its reliability and supply, an electric power monitoring system is indispensable in an electric power system. Currently, most electric power monitoring systems are designed for steady-state monitoring only. They may not be able to monitor instantaneous power disturbances, such as voltage surge, happened in electric power systems. In fact, instantaneous power disturbances are frequently found in electric power systems, which result in equipment failures and cause financial losses. Therefore, a novel electric power monitoring system is proposed in this thesis. Besides traditional functions, the proposed system is capable of monitoring and analyzing instantaneous power disturbances in electric power systems. Novelties of the proposed monitoring system are in the following three major aspects. Firstly, the proposed system is capable of monitoring instantaneous power disturbances. Unlike traditional monitoring systems, the proposed system captures not only statistical power quantities (e.g. kW, kWh), but also voltage and current waveforms. Since a considerable communication network bandwidth is required to transmit electric waveforms in a remote monitoring system, a novel waveform compression algorithm is proposed to realize real-time electric power waveform monitoring on low-speed communication networks (e.g. Zigbee). Secondly, the proposed system is capable of identifying various kinds of power disturbances automatically. It relieves electrical engineers from manned disturbance identification on preserved waveforms. Unlike traditional disturbance identification algorithms, the proposed system can identify not only voltage disturbances, but also current disturbances. Hence, it can provide a better chance in identifying more problems and disturbances in electric power systems. Thirdly, a novel time-frequency analysis method is proposed to analyze preserved waveforms. The proposed method is an improvement to the well-known Discrete Wavelet Packet Transform (DWPT). DWPT has been used by researchers and engineers to analyze disturbances and harmonics in electric power systems. However, DWPT is subjected to a non-uniform leakage problem, which has been discussed intensively in many studies. In order to tackle this issue, a frequency shifting scheme is introduced in the proposed method. A prototype has been implemented to demonstrate the feasibility of the proposed electric power monitoring system. There are two major components – a prototype meter and a central monitoring system. The performance of the prototype has been evaluated by conducting experiments and field tests. The capability of the proposed system for realtime remote monitoring has been verified on Zigbee network, which is a low-power, low speed wireless communication network.
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Kontos, Adamos C. "Construction of boundary matched equivalents for off-line lead-flow-type studies and transient stability analysis." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/13697.
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Mehryoon, Shah M. "Analysis and comparison of power loss and voltage drop of 15 kV and 20 kV medium voltage levels in the north substation of the Kabul power distrubution system by CYMDIST." Ohio : Ohio University, 2009. http://www.ohiolink.edu/etd/view.cgi?ohiou1258137124.
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Fernando, Kurukulasuriya Joseph Tilak Nihal. "Soft computing techniques in power system analysis." full-text, 2008. http://eprints.vu.edu.au/2025/1/thesis.pdf.
Full textAbstract:
Soft computing is a concept that has come into prominence in recent times and its application to power system analysis is still more recent. This thesis explores the application of soft computing techniques in the area of voltage stability of power systems. Soft computing, as opposed to conventional “hard” computing, is a technique that is tolerant of imprecision, uncertainty, partial truth and approximation. Its methods are based on the working of the human brain and it is commonly known as artificial intelligence. The human brain is capable of arriving at valid conclusions based on incomplete and partial data obtained from prior experience. It is an approximation of this process on a very small scale that is used in soft computing. Some of the important branches of soft computing (SC) are artificial neural networks (ANNs), fuzzy logic (FL), genetic computing (GC) and probabilistic reasoning (PR). The soft computing methods are robust and low cost. It is to be noted that soft computing methods are used in such diverse fields as missile guidance, robotics, industrial plants, pattern recognition, market prediction, patient diagnosis, logistics and of course power system analysis and prediction. However in all these fields its application is comparatively new and research is being carried out continuously in many universities and research institutions worldwide. The research presented in this thesis uses the soft computing method of Artificial Neural Networks (ANN’s) for the prediction of voltage instability in power systems. The research is very timely and current and would be a substantial contribution to the present body of knowledge in soft computing and voltage stability, which by itself is a new field. The methods developed in this research would be faster and more economical than presently available methods enabling their use online.
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Bi̇li̇r, Bülent. "Bifurcation analysis of nonlinear oscillations in power systems /." free to MU campus, to others for purchase, 2000. http://wwwlib.umi.com/cr/mo/fullcit?p9999273.
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Lee, Jae Ryong. "Analysis and simulation of dynamics of spacecraft power systems." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53568.
Full textAbstract:
Comprehensive analyses, including dc, small-signal and large-signal analyses, of the dynamics of various spacecraft power systems are performed. Systems' dynamics are analyzed for various operating modes, such as the shunt, battery-charge and battery-discharge modes, as well as the transition mode. Computer models using the EASY5 program are developed for the Direct Energy Transfer (DET) system, solar array switching system and partial shunt system to facilitate design, analysis and performance verification.
Large-signal analyses are performed to identify stability conditions and to predict large-signal dynamic behavior for each mode of operation. The equivalent source and load characteristics of a solar array power system with a constant-power load, shunt regulator, battery charger and discharger, are identified to predict large-signal dynamic behavior. Employing the equivalent source and load, the state trajectories of shunt failure, battery discharger failure and solar array/battery lockup are predicted and verified through time-domain simulations.
Small-signal analyses of the DET system are performed for the three modes of operation. The system loop gain is defined. Design guidelines for the feedback control loop of the shunt regulator, battery charger and discharger are developed to shape the system loop gain for the optimum bus dynamic performance and stability of the system. Designed subsystems are simulated both in frequency-domain and time-domain to verify the design concept.
Various spacecraft power systems, such as solar array switching systems, a partial shunt system, a peak power tracking system and the COBE (Cosmic Background Explorer) power system are analyzed and simulated. Design guidelines of the power conditioning equipment for each system are provided.<br>Ph. D.
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Rosado, Sebastian Pedro. "Analysis of Electric Disturbances from the Static Frequency Converter of a Pumped Storage Station." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/34448.
Full textAbstract:
The present work studies the disturbances created in the electric system of a pumped storage power plant, which is an hydraulic generation facility where the machines can work as turbines or pumps, by the operation of a static frequency converter (SFC). The SFC is used for starting the synchronous machines at the station when in the pump mode. During the starting process several equipment is connected to the SFC being possible to get affected by the disturbances generated. These disturbances mainly include the creation of transient overvoltages during the commutation of the semiconductor devices of the SFC and the introduction of harmonics in the network currents and voltages. This work analyzes the possible effects of the SFC operation over the station equipment based on computer simulations. For this purpose, the complete system was modeled and the starting process simulated in a computer transient simulator program. The work begins with a general review of the effects of electric disturbances over high voltage equipment and in particular of the disturbances generated by power electronics conversion equipment. Then the models for the different kind of equipment present in the system are discussed and formulated. The control system that governs the operation of the SFC during the starting process is analyzed later as well as the operation conditions. Once the model of the system is set up, the harmonic analysis of the electric network is done by frequency domain and time domain methods. Time domain methods are also employed for the analysis of the commutation transient produced by the SFC operation. Finally, the simulation results are used to evaluate the impact of the SFC operation on the station equipment, especially on the generator step up transformer.<br>Master of Science
50
Tamronglak, Surachet. "Analysis of power system disturbances due to relay hidden failures." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/39136.
Full textAbstract:
This research analyzes the linkage between power system disturbances and
failures in relaying systems. The annual disturbance reports prepared by the North
American Electric Reliability Council were examined. It has been found that
relaying system failures plays very important role in power system cascading
outages. The type of relaying system failures that are the most troublesome are the
ones that have a potential to remain hidden until being exposed by some abnormal
power system states to trigger relay misoperations.
Each commonly used relaying scheme in transmission system is examined
for any hidden failures that can lead to relay misoperations and multiple power
system contingencies. Each hidden failure mode has a region, called region of
vulnerability. Inside this region, some abnormal power system states can expose
the hidden failure. The reach of the region depends largely on the settings of the
relay in question.
A method of computing the relative importance of each region of
vulnerability, called vulnerability index, was proposed. The calculation of the
index can be based on some measurements of power system performances. In this
research, the stability measurements of the system following some contingencies
that may occur in the region are chosen. With this approach, vulnerable relays can
be identified.
A preventive method was proposed so that the number of relay
misoperations due to hidden failures and, ultimately, the number of power system
disturbances can be reduced.<br>Ph. D.