Engineering Commons^™

A Wide Area Hierarchical Voltage Control For Systems With High Wind Penetration And An Hvdc Overlay, Yidan Lu

Doctoral Dissertations

The modern power grid is undergoing a dramatic revolution. On the generation side, renewable resources are replacing fossil fuel in powering the system. On the transmission side, an AC-DC hybrid network has become increasingly popular to help reduce the transportation cost of electricity. Wind power, as one of the environmental friendly renewable resources, has taken a larger and larger share of the generation market. Due to the remote locations of wind plants, an HVDC overlay turns out to be attractive for transporting wind energy due to its superiority in long distance transmission of electricity.

While reducing environmental concern, the increasing …

Wide-Area Control Schemes To Improve Small Signal Stability In Power Systems, Meimanat Mahmoudi

Doctoral Dissertations

One of the main concerns for the secure and reliable operation of power systems is the small signal stability problem. In the complex and highly interconnected structure of future power systems, relying solely on operator responses and conventional controls cannot assure reliability. Therefore, there is a need for advanced Wide-Area Control Schemes (WACS) that can automatically respond to degradation of reliability in the system.

The main objective of this dissertation is to address two key challenges regarding the design and implementation of wide-area control schemes for damping inter-area oscillations. First is the high communication cost associated with optimal centralized control …

Design Considerations For Paralleling Multiple Chips In Sic Power Modules, Fei Yang

Masters Theses

With the benefits of fast switching speed, low on-resistance and high thermal conductivity, silicon carbide (SiC) devices are being implemented in converter designs with high efficiency and high power density. Consequently, SiC power modules are needed. However, some of the preestablished package designs for silicon based power modules are not suitable to manifest the advantages of SiC devices. Therefore, this thesis aims at optimizing the package design to utilize the fast switching capability of SiC devices.

First, the power loop parasitic inductance induced by the package can lead to large voltage spikes with the fast switching SiC device. It can …

Wide-Area Measurement-Driven Approaches For Power System Modeling And Analytics, Hesen Liu

Doctoral Dissertations

This dissertation presents wide-area measurement-driven approaches for power system modeling and analytics. Accurate power system dynamic models are the very basis of power system analysis, control, and operation. Meanwhile, phasor measurement data provide first-hand knowledge of power system dynamic behaviors. The idea of building out innovative applications with synchrophasor data is promising.

Taking advantage of the real-time wide-area measurements, one of phasor measurements’ novel applications is to develop a synchrophasor-based auto-regressive with exogenous inputs (ARX) model that can be updated online to estimate or predict system dynamic responses.

Furthermore, since auto-regressive models are in a big family, the ARX model …

High-Current Integrated Battery Chargers For Mobile Applications, Gabriel Alejo Gabian

Masters Theses

Battery charging circuits for mobile applications, such as smart phones and tablets, require both small area and low losses. In addition, to reduce the charging time, high current is needed through the converter. In this work, exploration of the Buck, the 3-Level Buck and the Hybrid Buck converter is performed over the input voltage, the total FET area and the load current. An analytical loss model for each topology is constructed and constrated by experimental results. In addition, packaging and bond wire impact on on-chip losses is analyzed by 3D modeling. Finally, a comparison between the topologies is presented determining …

Battery Energy Storage Emulation For Power System Applications, Jessica Danielle Boles

Masters Theses

The concept of energy storage for power systems has received increasingly more attention in recent decades, and the growing penetration of renewable energy sources has only escalated demand for it. Energy storage systems are excellent for balancing generation and load, for suppressing power fluctuations, and for providing other ancillary services to the grid. The Hardware Testbed (HTB) is a novel converter-based grid emulator created for studying the needs associated with high renewable penetration, but the system currently lacks a battery storage emulator. Thus, this work documents the development of a battery energy storage system (BESS) emulator for the HTB.

The …

Loss Model For Gallium Nitride Dc-Dc Buck Converter, Rushi P. Patel

Pursuit - The Journal of Undergraduate Research at The University of Tennessee

In recent years, more research has been done on Enhancement Mode Gallium Nitride (eGaN) converters, as the world is moving towards more power efficient converters. Power converters play a major role in efficiently controlling and converting electric energy used by machines, systems, and everyday products. The process to make converters more efficient was complicated and slow in the twentieth century. One of the important aspects in power electronics is to evaluate different losses and minimize losses to achieve high efficiency of the converter. With help of simulation tools such as MATLAB and LTspice, this process has become much faster and …

Electricity Market Designs For Demand Response From Residential Customers, Ailin Asadinejad

Doctoral Dissertations

The main purpose of this dissertation is to design an appropriate tariff program for residential customers that encourages customers to participate in the system while satisfying market operators and utilities goals. This research investigates three aspects critical for successful programs: tariff designs for DR, impact of renewable on such tariffs, and load elasticity estimates. First, both categories of DR are modeled based on the demand-price elasticity concept and used to design an optimum scheme for achieving the maximum benefit of DR. The objective is to not only reduce costs and improve reliability but also to increase customer acceptance of a …

Wide-Area Synchrophasor Data Server System And Data Analytics Platform, Dao Zhou

Doctoral Dissertations

As synchrophasor data start to play a significant role in power system operation and dynamic study, data processing and data analysis capability are critical to Wide-area measurement systems (WAMS). The Frequency Monitoring Network (FNET/GridEye) is a WAMS network that collects data from hundreds of Frequency Disturbance Recorders (FDRs) at the distribution level. The previous FNET/GridEye data center is limited by its data storage capability and computation power. Targeting scalability, extensibility, concurrency and robustness, a distributed data analytics platform is proposed to process large volume, high velocity dataset. A variety of real-time and non-real-time synchrophasor data analytics applications are hosted by …

Impedance-Based Stability Analysis And Controller Design Of Three-Phase Inverter-Based Ac Systems, Wenchao Cao

Doctoral Dissertations

Three-phase voltage-source power inverters are widely used for energy conversion in three-phase ac systems, such as renewable energy systems and microgrids. These three-phase inverter-based ac systems may suffer from small-signal instability issues due to the dynamic interactions among inverters and passive components in the systems. It is crucial for system integrators to analyze the system stability and design the inverter controller parameters during system planning and maintenance periods to guarantee stable system operation. The impedance-based approach can analyze the stability of source-load systems, by applying the Nyquist stability criterion or the generalized Nyquist stability criterion (GNC) to the impedance ratio …

Management Of Islanded Operation Of Microgirds, Md Riyasat Azim

Doctoral Dissertations

Distributed generations with continuously growing penetration levels offer potential solutions to energy security and reliability with minimum environmental impacts. Distributed Generations when connected to the area electric power systems provide numerous advantages. However, grid integration of distributed generations presents several technical challenges which has forced the systems planners and operators to account for the repercussions on the distribution feeders which are no longer passive in the presence of distributed generations.

Grid integration of distributed generations requires accurate and reliable islanding detection methodology for secure system operation. Two distributed generation islanding detection methodologies are proposed in this dissertation. First, a passive …

Electric Power System Operations With A Variable Series Reactor, Xiaohu Zhang

Doctoral Dissertations

Series FACTS devices, such as a Variable Series Reactor (VSR), have the ability to continuously regulate the transmission line reactance so as to control power ow. This research work evaluates the benefits brought by VSRs in different aspects of power system and develops efficient planning models and algorithms to provide optimal investment plan for the VSRs.

First, an optimization approach capable of finding both optimal locations and settings of VSRs under a specific operating condition is developed. The tool implements a full ac model as well as detailed models for different power system components.

Second, an optimization tool which can …

Design And Implementation Of Power Electronics For An Electric Bicycle, Kyle Jackson Goodrick, Jared Baxter, Jacob Dyer

Chancellor’s Honors Program Projects

No abstract provided.

A Wide-Area Analysis Of Shifts In Electric Power System Generation Profiles And High-Impact Event Scenarios, Micah Joel Till

Doctoral Dissertations

Often cited as the largest machine in the world, the electric power grid is a complex system, integral to modern life. Continuous technology advancements over the past hundred years have delivered improvements to both the system itself, e.g., wide-area management systems (WAMS), as well as modeling capabilities in order to better understand how that system functions. Phenomena that could once be simulated only in small, localized settings can now be studied from a wide-area perspective.

Chapter 1 briefly introduces the three major U.S. electric interconnections along with wide-area power system analysis tools and the benchmarked models used in this work. …

Co-Optimization Of Gas-Electricity Integrated Energy Systems Under Uncertainties, Linquan Bai

Doctoral Dissertations

In the United States, natural gas-fired generators have gained increasing popularity in recent years due to low fuel cost and emission, as well as the needed large gas reserves. Consequently, it is worthwhile to consider the high interdependency between the gas and electricity networks. In this dissertation, several co-optimization models for the optimal operation and planning of gas-electricity integrated energy systems (IES) are proposed and investigated considering uncertainties from wind power and load demands.

For the coordinated operation of gas-electricity IES: 1) an interval optimization based coordinated operating strategy for the gas-electricity IES is proposed to improve the overall system …

Peak Power Demand From Centrifugal Chillers Used To Comfort Condition The John C. Hodges Library, Summer F. Fabus, Jared A. Baxter, Kyle Jackson Goodrick, Divyani Rao, Kevin Chiang

Chancellor’s Honors Program Projects

No abstract provided.

Z Deviation Based Demand Side Control To Reduce Fidvr, Derek Brittian Lusby

Masters Theses

Accurate load modeling is key to depicting realistic system behavior in power system simulations. In the past, the use of static load models resulted in overly optimistic results, which led to unforeseen outages and issues following faults. One common cause of these types of unforeseen issues is Fault Induced Delayed Voltage Recovery (FIDVR). FIDVR occurs due to the stalling of single-phase residential air conditioners (A/C), and causes the voltage recovery after a fault to be slow. Improvements in load models over time have resulted in the capability of modeling load dynamics, and therefore better FIDVR.

A composite load model based …