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- Genre: Masters Thesis
Description
Advancements in technologies like the Internet of thing causes an increase in the presence of wireless transceivers. A cooperative communication between these transceivers opens a doorway for multiple novel applications. A mobile distributed transceiver architecture is a much more dynamic environment dictating the necessity of faster synchronization among the transceivers. A possibility of simultaneous synchronization in parallel with the communication will theoretically ensure a high-speed synchronization without affecting the data rate. One such system has been implemented using a Costas loop and an extension of such synchronization technique to the full-duplex model has also been addressed. The rise in spectral demand is hard to meet with the regular Time duplex and frequency duplex communication systems. A full-duplex system is theoretically expected to double the spectral efficiency. However it comes with tremendous challenges, This thesis works on one of those challenges in implementing full-duplex synchronization. A coherent full-duplex model is designed to overcome the issue of transmitter leakage modeled as injection pulling, A known solution for this effect has been used to resolve the issue and complete the coherent full-duplex model. This establishes the simultaneous synchronization and communication system.
ContributorsDhulipala, Sailesh (Author) / Zeinolabedinzadeh, Saeed (Thesis advisor) / Trichopoulos, Georgios C. (Committee member) / Allee, David (Committee member) / Arizona State University (Publisher)
Created2021
Description
This research primarily deals with the design and validation of the protection system for a large scale meshed distribution system. The large scale system simulation (LSSS) is a system level PSCAD model which is used to validate component models for different time-scale platforms, to provide a virtual testing platform for the Future Renewable Electric Energy Delivery and Management (FREEDM) system. It is also used to validate the cases of power system protection, renewable energy integration and storage, and load profiles. The protection of the FREEDM system against any abnormal condition is one of the important tasks. The addition of distributed generation and power electronic based solid state transformer adds to the complexity of the protection. The FREEDM loop system has a fault current limiter and in addition, the Solid State Transformer (SST) limits the fault current at 2.0 per unit. Former students at ASU have developed the protection scheme using fiber-optic cable. However, during the NSF-FREEDM site visit, the National Science Foundation (NSF) team regarded the system incompatible for the long distances. Hence, a new protection scheme with a wireless scheme is presented in this thesis. The use of wireless communication is extended to protect the large scale meshed distributed generation from any fault. The trip signal generated by the pilot protection system is used to trigger the FID (fault isolation device) which is an electronic circuit breaker operation (switched off/opening the FIDs). The trip signal must be received and accepted by the SST, and it must block the SST operation immediately. A comprehensive protection system for the large scale meshed distribution system has been developed in PSCAD with the ability to quickly detect the faults. The validation of the protection system is performed by building a hardware model using commercial relays at the ASU power laboratory.
ContributorsSharma, Nitish (Author) / Karady, George G. (Thesis advisor) / Holbert, Keith E. (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2015
Description
Gas turbine engine for aircraft propulsion represents one of the most physics-complex and safety-critical systems in the world. Its failure diagnostic is challenging due to the complexity of the model system, difficulty involved in practical testing and the infeasibility of creating homogeneous diagnostic performance evaluation criteria for the diverse engine makes.
NASA has designed and publicized a standard benchmark problem for propulsion engine gas path diagnostic that enables comparisons among different engine diagnostic approaches. Some traditional model-based approaches and novel purely data-driven approaches such as machine learning, have been applied to this problem.
This study focuses on a different machine learning approach to the diagnostic problem. Some most common machine learning techniques, such as support vector machine, multi-layer perceptron, and self-organizing map are used to help gain insight into the different engine failure modes from the perspective of big data. They are organically integrated to achieve good performance based on a good understanding of the complex dataset.
The study presents a new hierarchical machine learning structure to enhance classification accuracy in NASA's engine diagnostic benchmark problem. The designed hierarchical structure produces an average diagnostic accuracy of 73.6%, which outperforms comparable studies that were most recently published.
NASA has designed and publicized a standard benchmark problem for propulsion engine gas path diagnostic that enables comparisons among different engine diagnostic approaches. Some traditional model-based approaches and novel purely data-driven approaches such as machine learning, have been applied to this problem.
This study focuses on a different machine learning approach to the diagnostic problem. Some most common machine learning techniques, such as support vector machine, multi-layer perceptron, and self-organizing map are used to help gain insight into the different engine failure modes from the perspective of big data. They are organically integrated to achieve good performance based on a good understanding of the complex dataset.
The study presents a new hierarchical machine learning structure to enhance classification accuracy in NASA's engine diagnostic benchmark problem. The designed hierarchical structure produces an average diagnostic accuracy of 73.6%, which outperforms comparable studies that were most recently published.
ContributorsWu, Qiyu (Author) / Si, Jennie (Thesis advisor) / Wu, Teresa (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2015
Description
This thesis provides a cost to benefit analysis of the proposed next generation of distribution systems- the Future Renewable Electric Energy Distribution Management (FREEDM) system. With the increasing penetration of renewable energy sources onto the grid, it becomes necessary to have an infrastructure that allows for easy integration of these resources coupled with features like enhanced reliability of the system and fast pro-tection from faults. The Solid State Transformer (SST) and the Fault Isolation Device (FID) make for the core of the FREEDM system and have huge investment costs.
Some key features of the FREEDM system include improved power flow control, compact design and unity power factor operation. Customers may observe a reduction in the electricity bill by a certain fraction for using renewable sources of generation. There is also a possibility of huge subsidies given to encourage use of renewable energy. This thesis is an attempt to quantify the benefits offered by the FREEDM system in monetary terms and to calculate the time in years required to gain a return on investments made. The elevated cost of FIDs needs to be justified by the advantages they offer. The result of different rates of interest and how they influence the payback period is also studied. The payback periods calculated are observed for viability. A comparison is made between the active power losses on a certain distribution feeder that makes use of distribution level magnetic transformers versus one that makes use of SSTs. The reduction in the annual active power losses in the case of the feeder using SSTs is translated onto annual savings in terms of cost when compared to the conventional case with magnetic transformers. Since the FREEDM system encourages operation at unity power factor, the need for installing capacitor banks for improving the power factor is eliminated and this re-flects in savings in terms of cost. The FREEDM system offers enhanced reliability when compared to a conventional system. The payback periods observed support the concept of introducing the FREEDM system.
Some key features of the FREEDM system include improved power flow control, compact design and unity power factor operation. Customers may observe a reduction in the electricity bill by a certain fraction for using renewable sources of generation. There is also a possibility of huge subsidies given to encourage use of renewable energy. This thesis is an attempt to quantify the benefits offered by the FREEDM system in monetary terms and to calculate the time in years required to gain a return on investments made. The elevated cost of FIDs needs to be justified by the advantages they offer. The result of different rates of interest and how they influence the payback period is also studied. The payback periods calculated are observed for viability. A comparison is made between the active power losses on a certain distribution feeder that makes use of distribution level magnetic transformers versus one that makes use of SSTs. The reduction in the annual active power losses in the case of the feeder using SSTs is translated onto annual savings in terms of cost when compared to the conventional case with magnetic transformers. Since the FREEDM system encourages operation at unity power factor, the need for installing capacitor banks for improving the power factor is eliminated and this re-flects in savings in terms of cost. The FREEDM system offers enhanced reliability when compared to a conventional system. The payback periods observed support the concept of introducing the FREEDM system.
ContributorsRaman, Apurva (Author) / Heydt, Gerald (Thesis advisor) / Karady, George G. (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2015
Description
The work presented in this manuscript has the overarching theme of radiation. The two forms of radiation of interest are neutrons, i.e. nuclear, and electric fields. The ability to detect such forms of radiation have significant security implications that could also be extended to very practical industrial applications. The goal is therefore to detect, and even image, such radiation sources.
The method to do so revolved around the concept of building large-area sensor arrays. By covering a large area, we can increase the probability of detection and gather more data to build a more complete and clearer view of the environment. Large-area circuitry can be achieved cost-effectively by leveraging the thin-film transistor process of the display industry. With production of displays increasing with the explosion of mobile devices and continued growth in sales of flat panel monitors and television, the cost to build a unit continues to decrease.
Using a thin-film process also allows for flexible electronics, which could be taken advantage of in-house at the Flexible Electronics and Display Center. Flexible electronics implies new form factors and applications that would not otherwise be possible with their single crystal counterparts. To be able to effectively use thin-film technology, novel ways of overcoming the drawbacks of the thin-film process, namely the lower performance scale.
The two deliverable devices that underwent development are a preamplifier used in an active pixel sensor for neutron detection and a passive electric field imaging array. This thesis will cover the theory and process behind realizing these devices.
The method to do so revolved around the concept of building large-area sensor arrays. By covering a large area, we can increase the probability of detection and gather more data to build a more complete and clearer view of the environment. Large-area circuitry can be achieved cost-effectively by leveraging the thin-film transistor process of the display industry. With production of displays increasing with the explosion of mobile devices and continued growth in sales of flat panel monitors and television, the cost to build a unit continues to decrease.
Using a thin-film process also allows for flexible electronics, which could be taken advantage of in-house at the Flexible Electronics and Display Center. Flexible electronics implies new form factors and applications that would not otherwise be possible with their single crystal counterparts. To be able to effectively use thin-film technology, novel ways of overcoming the drawbacks of the thin-film process, namely the lower performance scale.
The two deliverable devices that underwent development are a preamplifier used in an active pixel sensor for neutron detection and a passive electric field imaging array. This thesis will cover the theory and process behind realizing these devices.
ContributorsChung, Hugh E (Author) / Allee, David R. (Thesis advisor) / Papandreou-Suppappola, Antonia (Committee member) / Holbert, Keith E. (Committee member) / Arizona State University (Publisher)
Created2015
Description
As photons, electrons, and neutrons traverse a medium, they impart their energy in ways that are analytically difficult to describe. Monte Carlo methods provide valuable insight into understanding this behavior, especially when the radiation source or environment is too complex to simplify. This research investigates simulating various radiation sources using the Monte Carlo N-Particle (MCNP) transport code, characterizing their impact on various materials, and comparing the simulation results to general theory and measurements.
A total of five sources were of interest: two photon sources of different incident particle energies (3.83 eV and 1.25 MeV), two electron sources also of different energies (30 keV and 100 keV), and a californium-252 (Cf-252) spontaneous fission neutron source. Lateral and vertical programmable metallization cells (PMCs) were developed by other researchers for exposure to these photon and electron sources, so simplified PMC models were implemented in MCNP to estimate the doses and fluences. Dose rates measured around the neutron source and the predicted maximum activity of activation foils exposed to the neutrons were determined using MCNP and compared to experimental results obtained from gamma-ray spectroscopy.
The analytical fluence calculations for the photon and electron cases agreed with MCNP results, and differences are due to MCNP considering particle movements that hand calculations do not. Doses for the photon cases agreed between the analytical and simulated results, while the electron cases differed by a factor of up to 4.8. Physical dose rate measurements taken from the neutron source agreed with MCNP within the 10% tolerance of the measurement device. The activity results had a percent error of up to 50%, which suggests a need to further evaluate the spectroscopy setup.
A total of five sources were of interest: two photon sources of different incident particle energies (3.83 eV and 1.25 MeV), two electron sources also of different energies (30 keV and 100 keV), and a californium-252 (Cf-252) spontaneous fission neutron source. Lateral and vertical programmable metallization cells (PMCs) were developed by other researchers for exposure to these photon and electron sources, so simplified PMC models were implemented in MCNP to estimate the doses and fluences. Dose rates measured around the neutron source and the predicted maximum activity of activation foils exposed to the neutrons were determined using MCNP and compared to experimental results obtained from gamma-ray spectroscopy.
The analytical fluence calculations for the photon and electron cases agreed with MCNP results, and differences are due to MCNP considering particle movements that hand calculations do not. Doses for the photon cases agreed between the analytical and simulated results, while the electron cases differed by a factor of up to 4.8. Physical dose rate measurements taken from the neutron source agreed with MCNP within the 10% tolerance of the measurement device. The activity results had a percent error of up to 50%, which suggests a need to further evaluate the spectroscopy setup.
ContributorsBowler, Herbert (Author) / Holbert, Keith E. (Thesis advisor) / Barnaby, Hugh J (Committee member) / Clark, Lawrence T (Committee member) / Arizona State University (Publisher)
Created2014
Description
The development of new policies favoring integration of renewable energy into the grid has created a need to relook at our existing infrastructure resources and at the way the power system is currently operated. Also, the needs of electric energy markets and transmission/generation expansion planning has created a niche for development of new computationally efficient and yet reliable, simple and robust power flow tools for such studies. The so called dc power flow algorithm is an important power flow tool currently in use. However, the accuracy and performance of dc power flow results is highly variable due to the various formulations which are in use. This has thus intensified the interest of researchers in coming up with better equivalent dc models that can closely match the performance of ac power flow solution.
This thesis involves the development of novel hot start dc model using a power transfer distribution factors (PTDFs) approach. This document also discusses the problems of ill-conditioning / rank deficiency encountered while deriving this model. This model is then compared to several dc power flow models using the IEEE 118-bus system and ERCOT interconnection both as the base case ac solution and during single-line outage contingency analysis. The proposed model matches the base case ac solution better than contemporary dc power flow models used in the industry.
This thesis involves the development of novel hot start dc model using a power transfer distribution factors (PTDFs) approach. This document also discusses the problems of ill-conditioning / rank deficiency encountered while deriving this model. This model is then compared to several dc power flow models using the IEEE 118-bus system and ERCOT interconnection both as the base case ac solution and during single-line outage contingency analysis. The proposed model matches the base case ac solution better than contemporary dc power flow models used in the industry.
ContributorsSood, Puneet (Author) / Tylavsky, Daniel J (Thesis advisor) / Vittal, Vijay (Committee member) / Ayyanar, Raja (Committee member) / Arizona State University (Publisher)
Created2014
Description
Improving solar cell efficiency is an enormously powerful driver of the cost reduction of solar power. While the silicon solar cell efficiency approaches theoretical limits, many thin-film solar cell technologies fall behind. In particular, cadmium telluride (CdTe) solar cells have only reached a maximum efficiency of 22.1%. One of the challenges associated with the development of CdTe solar cells is due its high electron affinity and the difficulty of achieving heavy p-type doping. This challenge results in the formation of a Schottky barrier at the hole contact, which reduces solar cell efficiency, primarily through the reduction of open circuit voltage (Voc) and fill factor (FF). The Schottky barrier makes the characterization of the actual solar cell p-n junction through current voltage (I-V), capacitance voltage (C-V), and thermal admittance spectroscopy (TAS) more difficult and not straightforward. However, interpreted through accurate physical models and under the correct experimental conditions, these techniques can then also be used to extract the impact of the contact on device performance, chiefly through analysis of the barrier height. Additionally, characterization of the open circuit voltage as a function of the illumination intensity (Suns-Voc) and the open circuit voltage as a function of temperature [Voc(T)] offer insight into the potential impact of the contact barrier. A comprehensive review of characterization of the barrier through the above techniques is given, primarily through a two-diode model. Further, a discussion of the utility of electrochemical capacitance-voltage (ECV) profiling to recover carrier concentrations in device regions otherwise difficult to access through traditional C-V measurements is provided along with modeling to support this conclusion. A discussion of and justification for the experimental extraction of barrier height from TAS measurements are also provided. Experimentally measured Voc(T), C-V, and Suns-Voc characteristics are presented and compared for a CdTe and a gallium arsenide (GaAs) solar cell. Experimental results indicate that the contact barriers and other possible non-idealities strongly affect the performance of the CdTe solar cell. Modeling results demonstrate the use of ECV to characterize solar cell absorbers can offer information unavailable via conventional C-V measurements.
ContributorsRosenblatt, Nathan (Author) / Zhang, Yong-Hang (Thesis advisor) / King, Richard R (Committee member) / Vasileska, Dragica (Committee member) / Arizona State University (Publisher)
Created2021
Description
Researchers have observed that the frequencies of leading digits in many man-made and naturally occurring datasets follow a logarithmic curve, with digits that start with the number 1 accounting for 30% of all numbers in the dataset and digits that start with the number 9 accounting for 5% of all numbers in the dataset. This phenomenon, known as Benford's Law, is highly repeatable and appears in lists of numbers from electricity bills, stock prices, tax returns, house prices, death rates, lengths of rivers, and naturally occurring images. This paper will demonstrate that human speech spectra also follow Benford's Law. This observation is used to motivate a new set of features that can be efficiently extracted from speech and demonstrate that these features can be used to classify between human speech and synthetic speech.
ContributorsHsu, Leo (Author) / Berisha, Visar (Thesis advisor) / Spanias, Andreas (Committee member) / Papandreou-Suppappola, Antonia (Committee member) / Arizona State University (Publisher)
Created2022
Description
This thesis presents an overview of the calculation and application of locational marginal prices in electric power systems particularly pertaining to the distribution system. The terminology proposed is a distribution locational marginal price or DLMP. The calculation of locational process in distribution engineering is conjectured and discussed. The use of quadratic programming for this calculation is proposed and illustrated. A small four bus test bed exemplifies the concept and then the concept is expanded to the IEEE 34 bus distribution system. Alternatives for the calculation are presented, and approximations are reviewed. Active power losses in the system are modeled and incorporated by two different methods. These calculation methods are also applied to the 34 bus system. The results from each method are compared to results found using the PowerWorld simulator. The application of energy management using the DLMP to control load is analyzed as well. This analysis entails the use of the DLMP to cause certain controllable loads to decrease when the DLMP is high, and vice-versa. Tests are done to illustrate the impact of energy management using DLMPs for residential, commercial, and industrial controllable loads. Results showing the dynamics of the loads are shown. The use and characteristics of Matlab function FMINCON are presented in an appendix.
ContributorsSteffan, Nick (Author) / Heydt, Gerald T (Thesis advisor) / Hedman, Kory (Committee member) / Karady, George G. (Committee member) / Arizona State University (Publisher)
Created2013