Open Access. Powered by Scholars. Published by Universities.®

Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Electrical and Computer Engineering

Doctoral Dissertations

Theses/Dissertations

Microgrid

Articles 1 - 8 of 8

Full-Text Articles in Engineering

Development Of Digital Twin Applications In Power Systems To Improve Operation Of Emerging Grid Technology, Jeremy Till Aug 2024

Development Of Digital Twin Applications In Power Systems To Improve Operation Of Emerging Grid Technology, Jeremy Till

Doctoral Dissertations

Power systems are continuously increasing in penetration of renewable energy resources and new technologies. Carbon-neutral requirements across the United States act as a catalyst forcing wide spread acceleration of these implementations. However, grid advancements exacerbate existing problems and potentially create new issues. New technologies for system planning and operation must be developed alongside the advancement of power systems. One such new technology is digital twins. Digital twins are a relatively new research topic in power systems. The main concept of a digital twin is a model of a real-world system that can run online with the physical system utilizing measurement …


Converter-Based Microgrid Testing Platform Development And Fault Detection Method For Inverter-Based Resources By Utilizing Instantaneous Power Theory, Nattapat Praisuwanna Aug 2024

Converter-Based Microgrid Testing Platform Development And Fault Detection Method For Inverter-Based Resources By Utilizing Instantaneous Power Theory, Nattapat Praisuwanna

Doctoral Dissertations

Renewable energy sources (RESs) are rapidly being installed into electric systems. Most RESs are inverter-based distributed generations (IDGs). To better manage energy from IDGs, microgrids will play a crucial role. However, microgrids that have high penetration of IDG will have modification in fault current levels and bidirectional power flow causing protective devices to misoperate, so the traditional protection system does not correctly function in the microgrids. Therefore, the integration of IDGs into the microgrids establishes some significant consequences on protection systems.

Overcurrent protection is widely utilized in the electric distribution systems today; however, it is sometimes difficult to distinguish between …


Stability Analysis Of Microgrids Using Markov Jump Linear Systems, Gilles Mpembele Jan 2021

Stability Analysis Of Microgrids Using Markov Jump Linear Systems, Gilles Mpembele

Doctoral Dissertations

"This research discusses stochastic models for a microgrid operating between standalone and grid-tied modes. The transitions between different modes are modeled as a continuous-time Markov chain (CTMC). In each operating mode, the system is modeled using conventional differential algebraic equations (DAEs), linearized around some equilibrium point.

In Topic-I, a model is developed using the Stochastic Hybrid Systems (SHSs) formulation. The microgrid is modeled as a Markov jump linear system (MJLS), which is a type of SHS in which the discrete events evolve according to a Continuous Time Markov Chain (CTMC). The model allows for the derivation of Ordinary Differential Equations …


Three-Phase Power Converter Based Real-Time Synchronous Generator Emulation, Liu Yang Dec 2015

Three-Phase Power Converter Based Real-Time Synchronous Generator Emulation, Liu Yang

Doctoral Dissertations

To bridge the gap between power system research and their real application in power grids, a Hardware Test-Bed (HTB) with modular three-phase power converters has been developed at the CURENT center, the University of Tennessee, Knoxville, to emulate transmission level power systems with actual power flowing.

This dissertation focuses on the development and verification of a real-time synchronous generator (SG) emulator in the HTB. The research involved in this dissertation aims at designing a proper control to achieve emulator performance goal and investigating the sources of error and its influence on interconnected SG-emulator networks.

First, different interface algorithms (IAs) are …


Gain Tuning Of Proportional Integral Controller Based On Multiobjective Optimization And Controller Hardware-In-Loop Microgrid Setup, Kumaraguru Prabakar Dec 2015

Gain Tuning Of Proportional Integral Controller Based On Multiobjective Optimization And Controller Hardware-In-Loop Microgrid Setup, Kumaraguru Prabakar

Doctoral Dissertations

Proportional integral (PI) control is a commonly used industrial controller framework. This PI controller needs to be tuned to obtain desired response from the process under control. Tuning methods available in literature by and large need sophisticated mathematical modelling, and simplifications in the plant model to perform gain tuning. The process of obtaining approximate plant model conceivably become time consuming and produce less accurate results. This is due to the simplifications desired by the power system applications especially when power electronics based inverters are used in it. Optimal gain selection for PI controllers becomes crucial for microgrid application. Because of …


Small Signal Modeling And Analysis Of Microgrid Systems, Md. Rasheduzzaman Jan 2015

Small Signal Modeling And Analysis Of Microgrid Systems, Md. Rasheduzzaman

Doctoral Dissertations

This dissertation focuses on small-signal modeling and analysis of inverter based microgrid systems. The proposed microgrid consists of two microsources placed on two different buses. The buses are connected using a distribution feeder with some impedance. The proposed microgrid can operate with the grid support, or without the grid support. When operated without the grid support, the standalone system’s microsources participate in controlling the system voltage and frequency. For a non-inertia source, such as the inverter, the load perturbations play an important role in system dynamics. In paper-I, such complex system was studied.

In the grid-tied mode, the microsources share …


Optimization In Microgrid Design And Energy Management, Tu Anh Nguyen Jan 2014

Optimization In Microgrid Design And Energy Management, Tu Anh Nguyen

Doctoral Dissertations

"The dissertation is composed of three papers, which cover microgrid systems performance characterization, optimal sizing for energy storage system and stochastic optimization of microgrid operation. In the first paper, a complete Photovoltaic-Vanadium Redox Battery (VRB) microgrid is characterized holistically. The analysis is based on a prototype system installation deployed at Fort Leonard Wood, Missouri, USA. In the second paper, the optimal sizing of power and energy ratings for a VRB system in isolated and grid-connected microgrids is proposed. An analytical method is developed to solve the problem based on a per-day cost model in which the operating cost is obtained …


Modeling And Optimization Of Energy Storage System For Microgrid, Xin Qiu Jan 2014

Modeling And Optimization Of Energy Storage System For Microgrid, Xin Qiu

Doctoral Dissertations

"The vanadium redox flow battery (VRB) is well suited for the applications of microgrid and renewable energy. This thesis will have a practical analysis of the battery itself and its application in microgrid systems. The first paper analyzes the VRB use in a microgrid system.

The first part of the paper develops a reduced order circuit model of the VRB and analyzes its experimental performance efficiency during deployment. The statistical methods and neural network approximation are used to estimate the system parameters. The second part of the paper addresses the implementation issues of the VRB application in a photovoltaic-based microgrid …