ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
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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.
system which is a time function of the temperature defined by its thermal class. A large
quantity of studies and international standards have been published indicating the
possibility of increasing the thermal class of cellulose based materials when immersed
in natural esters which are superior to traditional mineral oils. Thus, a transformer
having thermally upgraded Kraft paper and natural ester dielectric fluid can be
classified as a high temperature insulation system. Such a transformer can also
operate at temperatures 20C higher than its mineral oil equivalent, holding additional
loading capability without losing life expectancy. This thesis focuses on evaluating
the use of this feature as an additional capability for enhancing the loadability and/or
extending the life of the distribution transformers for the Phoenix based utility - SRP
using FR3 brand natural ester dielectric fluid.
Initially, different transformer design options to use this additional loadability
are compared allowing utilities to select an optimal FR3 filled transformer design
for their application. Yearlong load profiles for SRP distribution transformers, sized
conventionally on peak load demands, are analyzed for their oil temperatures, winding
temperatures and loss of insulation life. It is observed that these load profiles can be
classified into two types: 1) Type-1 profiles with high peak and high average loads,
and 2) Type-2 profiles with comparatively low peak and low average load.
For the Type 1 load profiles, use of FR3 natural ester fluid with the same nominal
rating showed 7.4 times longer life expectation. For the Type 2 load profiles, a new
way of sizing ester filled transformers based on both average and peak load, instead of
only peak load, called “Sustainable Peak Loading” showed smaller size transformers
can handle the same yearly peak loads while maintaining superior insulation lifespan.
It is additionally possible to have reduction in the total energy dissipation over the
year. A net present value cost savings up to US$1200 per transformer quantifying
benefits of the life extension and the total ownership cost savings up to 30% for
sustainable peak loading showed SRP distribution transformers can gain substantial
economic savings when the distribution transformer fleet is replaced with FR3 ester
filled units.
This Thesis describes the development of the novel two-stage on-line DSA scheme using phasor measurement and load forecasting data. The computational scheme of the new system determines the steady state stability and identifies endangerments in a small time frame near real time. The new on-line DSA system will periodically examine system status and predict system endangerments in the near future every 30 minutes. System real-time operating conditions will be determined by state estimation using phasor measurement data. The assessment of transient stability is carried out by running the time-domain simulation using a forecast working point as the initial condition. The forecast operating point is calculated by DC optimal power flow based on forecast load.
In this report, HEPF will be used for two power system analysis purposes:
a. Estimating the saddle-node bifurcation point (SNBP) of a system
b. Developing reduced-order network equivalents for distribution systems.
Typically, the continuation power flow (CPF) is used to estimate the SNBP of a system, which involves solving multiple power-flow problems. One of the advantages of HEPF is that the solution is obtained as an analytical expression of the embedding parameter, and using this property, three of the proposed HEPF-based methods can es-timate the SNBP of a given power system without solving multiple power-flow prob-lems (if generator VAr limits are ignored). If VAr limits are considered, the mathemat-ical representation of the power-flow problem changes and thus an iterative process would have to be performed in order to estimate the SNBP of the system. This would typically still require fewer power-flow problems to be solved than CPF in order to estimate the SNBP.
Another proposed application is to develop reduced order network equivalents for radial distribution networks that retain the nonlinearities of the eliminated portion of the network and hence remain more accurate than traditional Ward-type reductions (which linearize about the given operating point) when the operating condition changes.
Different ways of accelerating the convergence of the power series obtained as a part of HEPF, are explored and it is shown that the eta method is the most efficient of all methods tested.
The local-measurement-based methods of estimating the SNBP are studied. Non-linear Thévenin-like networks as well as multi-bus networks are built using model data to estimate the SNBP and it is shown that the structure of these networks can be made arbitrary by appropriately modifying the nonlinear current injections, which can sim-plify the process of building such networks from measurements.