Matching Items (18)
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- All Subjects: energy
- Genre: Doctoral Dissertation
- Creators: Vittal, Vijay
- Creators: Buttry, Daniel
- Member of: ASU Electronic Theses and Dissertations
Description
Transmission expansion planning (TEP) is a complex decision making process that requires comprehensive analysis to determine the time, location, and number of electric power transmission facilities that are needed in the future power grid. This dissertation investigates the topic of solving TEP problems for large power systems. The dissertation can be divided into two parts. The first part of this dissertation focuses on developing a more accurate network model for TEP study. First, a mixed-integer linear programming (MILP) based TEP model is proposed for solving multi-stage TEP problems. Compared with previous work, the proposed approach reduces the number of variables and constraints needed and improves the computational efficiency significantly. Second, the AC power flow model is applied to TEP models. Relaxations and reformulations are proposed to make the AC model based TEP problem solvable. Third, a convexified AC network model is proposed for TEP studies with reactive power and off-nominal bus voltage magnitudes included in the model. A MILP-based loss model and its relaxations are also investigated. The second part of this dissertation investigates the uncertainty modeling issues in the TEP problem. A two-stage stochastic TEP model is proposed and decomposition algorithms based on the L-shaped method and progressive hedging (PH) are developed to solve the stochastic model. Results indicate that the stochastic TEP model can give a more accurate estimation of the annual operating cost as compared to the deterministic TEP model which focuses only on the peak load.
ContributorsZhang, Hui (Author) / Vittal, Vijay (Thesis advisor) / Heydt, Gerald T (Thesis advisor) / Mittelmann, Hans D (Committee member) / Hedman, Kory W (Committee member) / Arizona State University (Publisher)
Created2013
Description
Mechanisms for oxygen reduction are proposed for three distinct cases covering two ionic liquids of fundamentally different archetypes and almost thirty orders of magnitude of proton activity. Proton activity is treated both extrinsically by varying the concentration and intrinsically by selecting proton donors with a wide range of aqueous pKa values. The mechanism of oxygen reduction in ionic liquids is introduced by way of the protic ionic liquid (pIL) triethylammonium triflate (TEATf) which shares some similarities with aqueous acid solutions. Oxygen reduction in TEATf begins as the one electron rate limited step to form superoxide, O2*-, which is then rapidly protonated by the pIL cation forming the perhydroxyl radical, HO2*. The perhydroxyl radical is further reduced to peroxidate (HO2-) and hydrogen peroxide in proportions in accordance with their pKa. The reaction does not proceed beyond this point due to the adsorption of the conjugate base triethylammine interfering with the disproportionation of hydrogen peroxide. This work demonstrates that this mechanism is consistent across Pt, Au, Pd, and Ag electrodes. Two related sets of experiments were performed in the inherently aprotic ionic liquid 1-butyl-2,3-dimethylimidazolium triflate (C4dMImTf). The first involved the titration of acidic species of varying aqueous pKa into the IL while monitoring the extent of oxygen reduction as a function of pKa and potential on Pt and glassy carbon (GC) electrodes. These experiments confirmed the greater propensity of Pt to reduce oxygen by its immediate and abrupt transition from one electron reduction to four electron reduction, while oxygen reduction on GC gradually approaches four electron reduction as the potentials were driven more cathodic. The potential at which oxygen reduction initiates shows general agreement with the Nernst equation and the acid's tabulated aqueous pKa value, however at the extremely acidic end, a small deviation is observed. The second set of experiments in C4dMImTf solicited water as the proton donor for oxygen reduction in an approximation of the aqueous alkaline case. The water content was varied between extremely dry (<0.1 mol% H2O) and saturated (approximately 15.8 mol% H2O}). As the water content increased so too did the extent of oxygen reduction eventually approach two electrons on both Pt and GC. However, additional water led to a linear increase in the Tafel slope under enhanced mass transport conditions up to the point of 10 mol% water. This inhibition of oxygen adsorption is the result of the interaction between superoxide and water and more specifically is proposed to be associated with decomposition of theC4dMIm+ cation by hydroxide at the elevated temperatures required for the experiment. Oxygen reduction on both Pt and GC follows Nernstian behavior as the water content is increased. Separate mechanisms for oxygen reduction on Pt and GC are proposed based on the nature of the Nernstian response in these systems.
ContributorsZeller, Robert August (Author) / Friesen, Cody (Thesis advisor) / Sieradzki, Karl (Committee member) / Buttry, Daniel (Committee member) / Arizona State University (Publisher)
Created2011
Description
The electrode-electrolyte interface in electrochemical environments involves the understanding of complex processes relevant for all electrochemical applications. Some of these processes include electronic structure, charge storage, charge transfer, solvent dynamics and structure and surface adsorption. In order to engineer electrochemical systems, no matter the function, requires fundamental intuition of all the processes at the interface. The following work presents different systems in which the electrode-electrolyte interface is highly important. The first is a charge storage electrode utilizing percolation theory to develop an electrode architecture producing high capacities. This is followed by Zn deposition in an ionic liquid in which the deposition morphology is highly dependant on the charge transfer and surface adsorption at the interface. Electrode Architecture: A three-dimensional manganese oxide supercapacitor electrode architecture is synthesized by leveraging percolation theory to develop a hierarchically designed tri-continuous percolated network. The three percolated phases include a faradaically-active material, electrically conductive material and pore-former templated void space. The micropores create pathways for ionic conductivity, while the nanoscale electrically conducting phase provides both bulk conductivity and local electron transfer with the electrochemically active phase. Zn Electrodeposition: Zn redox in air and water stable N-ethyl-N-methylmorpholinium bis(trifluoromethanesulfonyl)imide, [C2nmm][NTf2] is presented. Under various conditions, characterization of overpotential, kinetics and diffusion of Zn species and morphological evolution as a function of overpotential and Zn concentration are analyzed. The surface stress evolution during Zn deposition is examined where grain size and texturing play significant rolls in compressive stress generation. Morphological repeatability in the ILs led to a novel study of purity in ionic liquids where it is found that surface adsorption of residual amine and chloride from the organic synthesis affect growth characteristics. The drivers of this work are to understand the processes occurring at the electrode-electrolyte interface and with that knowledge, engineer systems yielding optimal performance. With this in mind, the design of a bulk supercapacitor electrode architecture with excellent composite specific capacitances, as well as develop conditions producing ideal Zn deposition morphologies was completed.
ContributorsEngstrom, Erika (Author) / Friesen, Cody (Thesis advisor) / Buttry, Daniel (Committee member) / Sieradzki, Karl (Committee member) / Arizona State University (Publisher)
Created2011
Description
In the deregulated power system, locational marginal prices are used in transmission engineering predominantly as near real-time pricing signals. This work extends this concept to distribution engineering so that a distribution class locational marginal price might be used for real-time pricing and control of advanced control systems in distribution circuits. A formulation for the distribution locational marginal price signal is presented that is based on power flow sensitivities in a distribution system. A Jacobian-based sensitivity analysis has been developed for application in the distribution pricing method. Increasing deployment of distributed energy sources is being seen at the distribution level and this trend is expected to continue. To facilitate an optimal use of the distributed infrastructure, the control of the energy demand on a feeder node in the distribution system has been formulated as a multiobjective optimization problem and a solution algorithm has been developed. In multiobjective problems the Pareto optimality criterion is generally applied, and commonly used solution algorithms are decision-based and heuristic. In contrast, a mathematically-robust technique called normal boundary intersection has been modeled for use in this work, and the control variable is solved via separable programming. The Roy Billinton Test System (RBTS) has predominantly been used to demonstrate the application of the formulation in distribution system control. A parallel processing environment has been used to replicate the distributed nature of controls at many points in the distribution system. Interactions between the real-time prices in a distribution feeder and the nodal prices at the aggregated load bus have been investigated. The application of the formulations in an islanded operating condition has also been demonstrated. The DLMP formulation has been validated using the test bed systems and a practical framework for its application in distribution engineering has been presented. The multiobjective optimization yields excellent results and is found to be robust for finer time resolutions. The work shown in this report is applicable to, and has been researched under the aegis of the Future Renewable Electric Energy Delivery and Management (FREEDM) center, which is a generation III National Science Foundation engineering research center headquartered at North Carolina State University.
ContributorsRanganathan Sathyanarayana, Bharadwaj (Author) / Heydt, Gerald T (Thesis advisor) / Vittal, Vijay (Committee member) / Ayyanar, Raja (Committee member) / Zhang, Junshan (Committee member) / Arizona State University (Publisher)
Created2012
Description
Hydrogenases, the enzymes that reversibly convert protons and electrons to hydrogen, are used in all three domains of life. [NiFe]-hydrogenases are considered best suited for biotechnological applications because of their reversible inactivation with oxygen. Phylogenetically, there are four groups of [NiFe]-hydrogenases. The best characterized group, "uptake" hydrogenases, are membrane-bound and catalyze hydrogen oxidation in vivo. In contrast, the group 3 [NiFe]-hydrogenases are heteromultimeric, bifunctional enzymes that fulfill various cellular roles. In this dissertation, protein film electrochemistry (PFE) is used to characterize the catalytic properties of two group 3 [NiFe]-hydrogenases: HoxEFUYH from Synechocystsis sp. PCC 6803 and SHI from Pyrococcus furiosus. First, HoxEFUYH is shown to be biased towards hydrogen production. Upon exposure to oxygen, HoxEFUYH inactivates to two states, both of which can be reactivated on the timescale of seconds. Second, we show that PfSHI is the first example of an oxygen tolerant [NiFe]-hydrogenase that produces two inactive states upon exposure to oxygen. Both inactive states are analogous to those characterized for HoxEFUYH, but oxygen exposed PfSHI produces a greater fraction that reactivates at high potentials, enabling hydrogen oxidation in the presence of oxygen. Third, it is shown that removing the NAD(P)-reducing subunits from PfSHI leads to a decrease in bias towards hydrogen oxidation and renders the enzyme oxygen sensitive. Both traits are likely due to impaired intramolecular electron transfer. Mechanistic hypotheseses for these functional differences are considered.
ContributorsMcIntosh, Chelsea Lee (Author) / Jones, Anne K (Thesis advisor) / Ghirlanda, Giovanna (Committee member) / Buttry, Daniel (Committee member) / Arizona State University (Publisher)
Created2012
Description
Electric power systems are facing great challenges from environmental regulations, changes in demand due to new technologies like electric vehicle, as well as the integration of various renewable energy sources. These factors taken together require the development of new tools to help make policy and investment decisions for the future power grid. The requirements of a network equivalent to be used in such planning tools are very different from those assumed in the development of traditional equivalencing procedures. This dissertation is focused on the development, implementation and verification of two network equivalencing approaches on large power systems, such as the Eastern Interconnection. Traditional Ward-type equivalences are a class of equivalencing approaches but this class has some significant drawbacks. It is well known that Ward-type equivalents "smear" the injections of external generators over a large number of boundary buses. For newer long-term investment applications that take into account such things as greenhouse gas (GHG) regulations and generator availability, it is computationally impractical to model fractions of generators located at many buses. A modified-Ward equivalent is proposed to address this limitation such that the external generators are moved wholesale to some internal buses based on electrical distance. This proposed equivalencing procedure is designed so that the retained-line power flows in the equivalent match those in the unreduced (full) model exactly. During the reduction process, accommodations for special system elements are addressed, including static VAr compensators (SVCs), high voltage dc (HVDC) transmission lines, and phase angle regulators. Another network equivalencing approach based on the dc power flow assumptions and the power transfer distribution factors (PTDFs) is proposed. This method, rather than eliminate buses via Gauss-reduction, aggregates buses on a zonal basis. The bus aggregation approach proposed here is superior to the existing bus aggregation methods in that a) under the base case, the equivalent-system inter-zonal power flows exactly match those calculated using the full-network-model b) as the operating conditions change, errors in line flows are reduced using the proposed bus clustering algorithm c) this method is computationally more efficient than other bus aggregation methods proposed heretofore. A critical step in achieving accuracy with a bus aggregation approach is selecting which buses to cluster together and how many clusters are needed. Clustering in this context refers to the process of partitioning a network into subsets of buses. An efficient network clustering method is proposed based on the PTDFs and the data mining techniques. This method is applied to the EI topology using the "Saguaro" supercomputer at ASU, a resource with sufficient memory and computational capability for handling this 60,000-bus and 80,000-branch system. The network equivalents generated by the proposed approaches are verified and tested for different operating conditions and promising results have been observed.
ContributorsShi, Di (Author) / Tylavsky, Daniel J (Thesis advisor) / Vittal, Vijay (Committee member) / Hedman, Kory (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2012
Description
The uncertainty and variability associated with stochastic resources, such as wind and solar, coupled with the stringent reliability requirements and constantly changing system operating conditions (e.g., generator and transmission outages) introduce new challenges to power systems. Contemporary approaches to model reserve requirements within the conventional security-constrained unit commitment (SCUC) models may not be satisfactory with increasing penetration levels of stochastic resources; such conventional models pro-cure reserves in accordance with deterministic criteria whose deliverability, in the event of an uncertain realization, is not guaranteed. Smart, well-designed reserve policies are needed to assist system operators in maintaining reliability at least cost.
Contemporary market models do not satisfy the minimum stipulated N-1 mandate for generator contingencies adequately. This research enhances the traditional market practices to handle generator contingencies more appropriately. In addition, this research employs stochastic optimization that leverages statistical information of an ensemble of uncertain scenarios and data analytics-based algorithms to design and develop cohesive reserve policies. The proposed approaches modify the classical SCUC problem to include reserve policies that aim to preemptively anticipate post-contingency congestion patterns and account for resource uncertainty, simultaneously. The hypothesis is to integrate data-mining, reserve requirement determination, and stochastic optimization in a holistic manner without compromising on efficiency, performance, and scalability. The enhanced reserve procurement policies use contingency-based response sets and post-contingency transmission constraints to appropriately predict the influence of recourse actions, i.e., nodal reserve deployment, on critical transmission elements.
This research improves the conventional deterministic models, including reserve scheduling decisions, and facilitates the transition to stochastic models by addressing the reserve allocation issue. The performance of the enhanced SCUC model is compared against con-temporary deterministic models and a stochastic unit commitment model. Numerical results are based on the IEEE 118-bus and the 2383-bus Polish test systems. Test results illustrate that the proposed reserve models consistently outperform the benchmark reserve policies by improving the market efficiency and enhancing the reliability of the market solution at reduced costs while maintaining scalability and market transparency. The proposed approaches require fewer ISO discretionary adjustments and can be employed by present-day solvers with minimal disruption to existing market procedures.
Contemporary market models do not satisfy the minimum stipulated N-1 mandate for generator contingencies adequately. This research enhances the traditional market practices to handle generator contingencies more appropriately. In addition, this research employs stochastic optimization that leverages statistical information of an ensemble of uncertain scenarios and data analytics-based algorithms to design and develop cohesive reserve policies. The proposed approaches modify the classical SCUC problem to include reserve policies that aim to preemptively anticipate post-contingency congestion patterns and account for resource uncertainty, simultaneously. The hypothesis is to integrate data-mining, reserve requirement determination, and stochastic optimization in a holistic manner without compromising on efficiency, performance, and scalability. The enhanced reserve procurement policies use contingency-based response sets and post-contingency transmission constraints to appropriately predict the influence of recourse actions, i.e., nodal reserve deployment, on critical transmission elements.
This research improves the conventional deterministic models, including reserve scheduling decisions, and facilitates the transition to stochastic models by addressing the reserve allocation issue. The performance of the enhanced SCUC model is compared against con-temporary deterministic models and a stochastic unit commitment model. Numerical results are based on the IEEE 118-bus and the 2383-bus Polish test systems. Test results illustrate that the proposed reserve models consistently outperform the benchmark reserve policies by improving the market efficiency and enhancing the reliability of the market solution at reduced costs while maintaining scalability and market transparency. The proposed approaches require fewer ISO discretionary adjustments and can be employed by present-day solvers with minimal disruption to existing market procedures.
ContributorsSinghal, Nikita Ghanshyam (Author) / Hedman, Kory W (Thesis advisor) / Vittal, Vijay (Committee member) / Sankar, Lalitha (Committee member) / Pal, Anamitra (Committee member) / Arizona State University (Publisher)
Created2018
Description
The phrase water-energy nexus is commonly used to describe the inherent and critical interdependencies between the electric power system and the water supply systems (WSS). The key interdependencies between the two systems are the power plant’s requirement of water for the cooling cycle and the water system’s need of electricity for pumping for water supply. While previous work has considered the dependency of WSS on the electrical power, this work incorporates into an optimization-simulation framework, consideration of the impact of short and long-term limited availability of water and/or electrical energy.
This research focuses on the water supply system (WSS) facet of the multi-faceted optimization and control mechanism developed for an integrated water – energy nexus system under U.S. National Science Foundation (NSF) project 029013-0010 CRISP Type 2 – Resilient cyber-enabled electric energy and water infrastructures modeling and control under extreme mega drought scenarios. A water supply system (WSS) conveys water from sources (such as lakes, rivers, dams etc.) to the treatment plants and then to users via the water distribution systems (WDS) and/or water supply canal systems (WSCS). Optimization-simulation methodologies are developed for the real-time operation of water supply systems (WSS) under critical conditions of limited electrical energy and/or water availability due to emergencies such as extreme drought conditions, electric grid failure, and other severe conditions including natural and manmade disasters. The coupling between WSS and the power system was done through alternatively exchanging data between the power system and WSS simulations via a program control overlay developed in python.
A new methodology for WDS infrastructural-operational resilience (IOR) computation was developed as a part of this research to assess the real-time performance of the WDS under emergency conditions. The methodology combines operational resilience and component level infrastructural robustness to provide a comprehensive performance assessment tool.
The optimization-simulation and resilience computation methodologies developed were tested for both hypothetical and real example WDS and WSCS, with results depicting improved resilience for operations of the WSS under normal and emergency conditions.
This research focuses on the water supply system (WSS) facet of the multi-faceted optimization and control mechanism developed for an integrated water – energy nexus system under U.S. National Science Foundation (NSF) project 029013-0010 CRISP Type 2 – Resilient cyber-enabled electric energy and water infrastructures modeling and control under extreme mega drought scenarios. A water supply system (WSS) conveys water from sources (such as lakes, rivers, dams etc.) to the treatment plants and then to users via the water distribution systems (WDS) and/or water supply canal systems (WSCS). Optimization-simulation methodologies are developed for the real-time operation of water supply systems (WSS) under critical conditions of limited electrical energy and/or water availability due to emergencies such as extreme drought conditions, electric grid failure, and other severe conditions including natural and manmade disasters. The coupling between WSS and the power system was done through alternatively exchanging data between the power system and WSS simulations via a program control overlay developed in python.
A new methodology for WDS infrastructural-operational resilience (IOR) computation was developed as a part of this research to assess the real-time performance of the WDS under emergency conditions. The methodology combines operational resilience and component level infrastructural robustness to provide a comprehensive performance assessment tool.
The optimization-simulation and resilience computation methodologies developed were tested for both hypothetical and real example WDS and WSCS, with results depicting improved resilience for operations of the WSS under normal and emergency conditions.
ContributorsKhatavkar, Puneet (Author) / Mays, Larry W. (Thesis advisor) / Vittal, Vijay (Committee member) / Mascaro, Giuseppe (Committee member) / Fox, Peter (Committee member) / Zhang, Junshan (Committee member) / Arizona State University (Publisher)
Created2019
Description
This dissertation presents innovative techniques to develop performance-based models and complete transient models of induction motor drive systems with vector controls in electro-magnetic transient (EMT) and positive sequence transient stability (PSTS) simulation programs. The performance-based model is implemented by obtaining the characteristic transfer functions of perturbed active and reactive power consumptions with respect to frequency and voltage perturbations. This level of linearized performance-based model is suitable for the investigation of the damping of small-magnitude low-frequency oscillations. The complete transient model is proposed by decomposing the motor, converter and control models into d-q axes components and developing a compatible electrical interface to the positive-sequence network in the PSTS simulators. The complete transient drive model is primarily used to examine the system response subject to transient voltage depression considering increasing penetration of converter-driven motor loads.
For developing the performance-based model, modulations are performed on the supply side of the full drive system to procure magnitude and phase responses of active and reactive powers with respect to the supply voltage and frequency for a range of discrete frequency points. The prediction error minimization (PEM) technique is utilized to generate the curve-fitted transfer functions and corresponding bode plots. For developing the complete drive model in the PSTS simulation program, a positive-sequence voltage source is defined properly as the interface of the model to the external system. The dc-link of the drive converter is implemented by employing the average model of the PWM converter, and is utilized to integrate the line-side rectifier and machine-side inverter.
Numerical simulation is then conducted on sample test systems, synthesized with suitable characteristics to examine performance of the developed models. The simulation results reveal that with growing amount of drive loads being distributed in the system, the small-signal stability of the system is improved in terms of the desirable damping effects on the low-frequency system oscillations of voltage and frequency. The transient stability of the system is also enhanced with regard to the stable active power and reactive power controls of the loads, and the appropriate VAr support capability provided by the drive loads during a contingency.
For developing the performance-based model, modulations are performed on the supply side of the full drive system to procure magnitude and phase responses of active and reactive powers with respect to the supply voltage and frequency for a range of discrete frequency points. The prediction error minimization (PEM) technique is utilized to generate the curve-fitted transfer functions and corresponding bode plots. For developing the complete drive model in the PSTS simulation program, a positive-sequence voltage source is defined properly as the interface of the model to the external system. The dc-link of the drive converter is implemented by employing the average model of the PWM converter, and is utilized to integrate the line-side rectifier and machine-side inverter.
Numerical simulation is then conducted on sample test systems, synthesized with suitable characteristics to examine performance of the developed models. The simulation results reveal that with growing amount of drive loads being distributed in the system, the small-signal stability of the system is improved in terms of the desirable damping effects on the low-frequency system oscillations of voltage and frequency. The transient stability of the system is also enhanced with regard to the stable active power and reactive power controls of the loads, and the appropriate VAr support capability provided by the drive loads during a contingency.
ContributorsLiu, Yuan (Author) / Vittal, Vijay (Thesis advisor) / Undrill, John (Committee member) / Ayyanar, Raja (Committee member) / Qin, Jiangchao (Committee member) / Arizona State University (Publisher)
Created2016
Description
This investigation is divided into two portions linked together by the momentous reaches of electrochemistry science, principles influencing everyday phenomena as well as innovative research in the field of energy transformation. The first portion explores the strategies for flue gas carbon dioxide capture and release using electrochemical means. The main focus is in the role thiolates play as reversible strong nucleophiles with the ability to capture CO2 and form thiocarbonates. Carbon dioxide in this form is transported and separated from thiocarbonate through electrochemical oxidation to complete the release portion of this catch-and-release approach. Two testing design systems play a fundamental role in achieving an efficient CO2 catch and release process and were purposely build and adapted for this work. A maximum faradaic efficiency of seventeen percent was attained in the first membrane tests whose analysis is presented in this work. An efficiency close to thirty percent was attained with the membrane cell in recent experiments but have not been included in this manuscript.
The second portion of this manuscript studies bulk stress evolution resulting from insertion/extraction of lithium in/from a lithium manganese oxide spinel cathode structure. A cantilever-based testing system uses a sophisticated, high resolution capacitive technique capable of measuring beam deflections of the cathode in the subnanometer scale. Tensile stresses of up to 1.2 MPa are reported during delithiation along with compressive stresses of 1.0 MPa during lithiation. An analysis of irreversible charge loss is attributed to surface passivation phenomena with its associated stresses of formation following patterns of tensile stress evolution.
The second portion of this manuscript studies bulk stress evolution resulting from insertion/extraction of lithium in/from a lithium manganese oxide spinel cathode structure. A cantilever-based testing system uses a sophisticated, high resolution capacitive technique capable of measuring beam deflections of the cathode in the subnanometer scale. Tensile stresses of up to 1.2 MPa are reported during delithiation along with compressive stresses of 1.0 MPa during lithiation. An analysis of irreversible charge loss is attributed to surface passivation phenomena with its associated stresses of formation following patterns of tensile stress evolution.
ContributorsCastro De la Torre, Helme Atic (Author) / Friesen, Cody (Thesis advisor) / Buttry, Daniel (Committee member) / Bautista Martinez, Jose A (Committee member) / Arizona State University (Publisher)
Created2016