The next generation of U.S. Navy ships will see the integration of the propulsion and electrical systems as part of the all-electric ship. This new architecture brings advantages and challenges. One of the challenges is to develop a stable power system that can ride through various issues such as faults or changes in load. style='mso-spacerun:yes'> While terrestrial systems have been studied for a long time related to stability, the unique characteristics of the shipboard power system mean that not all of these results are directly applicable to the all-electric ship. Because of the new shipboard power system structure, more generators are required to be connected in parallel to supply the power needed. Control of parallel generators has been done for years in terrestrial systems; however, the application of an advanced control technique has not been applied in the All-Electric Ship. The challenge is to apply an advanced control technique to the all-electric shipboard power system that will maintain stability of multiple generator systems, keeping in mind that the generators could be dissimilar in ratings. style='mso-spacerun:yes'> For that reason, the control techniques used to solve the problem need to be developed or adapted for test cases that are similar to the electric ship configuration. This dissertation provides a description of an effort to implement a robust control scheme on the all-electric ship. style='mso-spacerun:yes'> The proposed solution is to apply H∞ Robust Control as an advanced control technique, with realistic constraints to keep the shipboard power system within stability margins during normal and abnormal operating scenarios. In this work, H∞ Robust Control has been developed in the form of state space equations which are optimized using linear matrix implementation. The developed H∞ Control has been implemented on the different operating scenarios to validate the functionality and to compare it with another control technique. style='mso-spacerun:yes'> Test case results for one-generator, two-generator similar and two-generator dissimilar have been described. style='mso-spacerun:yes'> Stability indicators have been determined and compared for various types of faults and transients for removing and adding static and dynamic loads. The research provides the foundation for applications of advanced control techniques for the next generation all-electric ship.

Recently, there has been an increase in the deployment of Phasor Measurement Units (PMUs) which has enabled real time, wide area monitoring of power systems. PMUs can synchronously measure operating parameters across the grid at typically 30 samples per second, compared to 1 sample per 2-5 seconds of a conventional Supervisory Control And Data Acquisition (SCADA) system. Such an explosion of data in power systems has provided an opportunity to make electrical grids more reliable. Additionally, it has brought a challenge to extract information from the massive amount of data. In this research, several data mining algorithms are used to extract information from synchrophasor data for improving situational awareness of power systems. The extracted information can be used for event detection, for reducing the dimension of data without losing information, and also to use it as heuristic to process future measurements. The methods proposed in this research work can be broadly classified into two parts: a) stream mining and b) dimension reduction. Stream mining algorithms provide solution utilizing state-of-the-art data stream mining algorithms such as Hoeffding Trees (HT). HT algorithm builds a decision tree by scanning the incoming data stream only once. The tree itself holds sufficient statistics in its leaves to grow the tree and also to make classification decisions of incoming data. Instead of using a large number of samples, which leads to a tree too large to accommodate in memory, the number of samples that are needed to split at each node is determined using Hoeffding bound (HB). HB keeps the size of the decision tree within bounds while also maintaining accuracies statistically competitive to traditional decision trees. Dimension reduction algorithms reduce dimension of the synchrophasor data by extracting maximum information from a huge data set without losing information. In this dissertation, both online and offline dimension reduction algorithms have been studied. The online dimension reduction uses an unsupervised method using principal components of the time series data. The offline method optimizes unique mutual information between the state of the power system and synchrophasor measurements. It optimizes the criteria by reducing redundant information while maximizing relevant information.

The shrinking of the world’s energy sources has prompted an unprecedented interest in renewable and clean energy sources such as photovoltaic (solar) array. Already popular in space and some industrial power system applications, photovoltaic arrays have yet to become a viable source of energy for most terrestrial applications. For several decades now, engineers have been striving to design reliable and affordable solar array based power systems. One popular approach to achieve reliability is the integration of Maximum Power Point Tracking (MPPT) technology in solar power system design. The purpose of this study was to gain more insight into the nature of photovoltaic arrays, in order to help engineers improve solar array systems efficiency and reliability. To this end, a detailed analysis and modeling of the electrical properties and parameters of solar arrays have been presented. Shading effects on solar arrays, as well as the benefits of incorporating MPPT technology in photovoltaic systems have also been studied. Finally an application of MPPT to grid connected systems will be introduced as part of the ongoing efforts of the Power Electronics Lab at the University of Central Florida to participate in the 2005 Future Energy Challenge.

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Utilities have been planning, building, and operating electrical distribution systems in much the same way for decades with great success. The electrical distribution system in the United States has been consistently reliable; an impressive feat considering its amazing complexity. However, in recent years, the electrical distribution system landscape has started to undergo drastic changes. Emerging applications of technologies such as distributed generation, communications, and power electronics offer both opportunities and challenges to power system operators as well as customers and developers. In this work, Graph Trace Analysis along with an integrated system model are used to develop algorithms and analysis methods necessary to facilitate the implementation of these new technologies on the electrical distribution system. A penetration limit analysis is developed to analyze the impact of distributed generation on radial distribution feeders. The analysis considers generation location, equipment rating, voltage violations, and flicker to determine the amount of generation that can be safely attached to a circuit. A real-time, hierarchical, model-based control method is developed that coordinates the operation of all control devices on electrical distribution circuits. The controller automatically compensates for changes in circuit topology as well as the addition or removal of control devices from the active circuit. Additionally, the controller allows the integration of modern, "smart" equipment with legacy control devices to facilitate incremental modernization strategies. Finally, a framework is developed to allow the testing of new analysis and control methodologies for electrical distribution systems. The framework can be used to test scenarios over multiple consecutive hourly or sub-hourly time points. The framework is used to demonstrate the effectiveness of the model-based controller versus existing operating methods for a distribution circuit test case. / Ph. D.

Due to the increasing trend towards energy saving of white goods appliances and the commercial viability of power electronic components, there has been an expansion in the use of solid state electronics and variable frequency drive motors in these applications. However, a major drawback of using such energy efficient loads is the introduction of current harmonics onto the local distribution grid. Furthermore, the proliferation of such devices elevates the harmonic content of the supply voltage and the ensuing potential impact on residential distribution networks. This thesis investigates the harmonic content generated by some representative household appliances and suggests a solution to minimize current harmonics by means of active filtering. An active filter circuit is proposed and simulations will be undertaken to compare filter performance when used as an active front end versus a feeder input compensator. Further, a hardware design of the filter was implemented to experimentally verify the filter operation. / Thesis / Master of Applied Science (MASc)

<p dir="ltr">The safe and reliable delivery of electricity is critical for the functioning of our modern society. However, high-impact, low-probability (HILP) catastrophic events (such as extreme weather caused by climate change, or cyber-physical attacks) pose an ever-growing threat to the power grid. At the same time, modern advancements in computational capabilities, communication infrastructure, and measurement technologies provide opportunities for new operation and control strategies that enhance the resilience of electric power systems to such HILP events. In this work, optimization-based operation and control approaches are proposed to improve resilience in two power systems applications. First, a real-time linearized-trajectory model-predictive controller (LTMPC) is developed for ensuring voltage, frequency, and transient (rotor angle) stability in systems engineered to operate as microgrids. Such microgrids are capable of seamlessly transitioning from grid-connected operation to an islanded mode and thus, enhance system resilience. The proposed LTMPC enables rapid deployment of such systems by reducing engineering costs and development time while maintaining stable operation. On the other hand, some power systems, such as distribution feeders, are not designed to operate as standalone microgrids. For these cases, a method is proposed for forming ad-hoc microgrids from intact sections of the damaged feeder in the aftermath of a HILP event. A feeder operating center-on-a-laptop (FOCAL) is introduced that coordinates the control of possibly hundreds of inverter-interfaced distributed energy resources (e.g., rooftop solar, battery storage) to improve system resilience. Theoretical analysis as well as numerical case studies and simulations of the proposed strategies are presented for both applications.</p>