Octanol/Water Partitioning Coefficients of PCB Mixtures for Environmental Fate and Transport

Polychlorinated biphenyls (PCBs) are a human and environmental toxin introduced to the environment from the 1920’s to the 1970’s from manufacturing items such as transformers and capacitors. PCBs remain in the environment today due to their low water solubility and resistance to chemical reaction. Due to their properties PCBs bioaccumulate in the environment and pose health risks to animals and humans, as they are deemed a probable carcinogen by the EPA. Octanol-water partitioning coefficients are a means of measuring how PCBs will travel in the environment, either partitioning to water or into organic carbon. Octanol-water partitioning coefficients will be determined for individual congeners of PCB and for solutions of groups of PCB congeners to see if mixtures of PCBs behaved differently from groups of PCBS. Partitioning coefficients were experimentally determined for individual PCBs and groups of PCBs

Power System Planning for Sustainable, Reliable, and Accessible Electricity: Models, Methods, and Metrics

Generation resources are shifting from centralized, high inertial, fossil fuel based to decentralized, no inertia, and variable renewable resources. The evolution of generation resources in electrical grids requires the transformation of the electrical grid infrastructure, and operation and planning procedures and standards. This dissertation takes four investigations into how to advance power system planning procedures and methods to integrate these resources into electrical grids ranging from minigrids to transmission systems. The first work addresses increasing energy access through development of sustainable off-grid minigrids through the introduction of an open-source planning tool which optimizes resource and equipment size and creates a distribution network placement map factoring in cost and reliability. The second work investigates the accuracy of measurement-based dynamic load modeling techniques used in transmission planning, highlighting the need for improvements of these commonly used methods due to a lack of correlation between model accuracy and output response error. The next work assesses the impact of dynamic loads and distributed energy resources (DERs), such as solar and wind, on transient voltage stability in transmission grids which is imperative to transmission stability and reliability. The last work evaluates modeling strategies and their impacts on the results of hosting capacity studies of DERs in transmission systems. These works highlight current shortcoming and ways for improvement and growth in traditional power system planning methods to accommodate these non-traditional resources. The ultimate goals of this work and the integration of these resources are to sustainably, affordably, and reliably transform electrical grids to meet climate and national security goals

Utility and Residential Solar Resource Assessment and Modeling for Alaska’s Railbelt Transmission System

Research Poste

Resilience in an Evolving Electrical Grid

Fundamental shifts in the structure and generation profile of electrical grids are occurring amidst increased demand for resilience. These two simultaneous trends create the need for new planning and operational practices for modern grids that account for the compounding uncertainties inherent in both resilience assessment and increasing contribution of variable inverter-based renewable energy sources. This work reviews the research work addressing the changing generation profile, state-of-the-art practices to address resilience, and research works at the intersection of these two topics in regards to electrical grids. The contribution of this work is to highlight the ongoing research in power system resilience and integration of variable inverter-based renewable energy sources in electrical grids, and to identify areas of current and further study at this intersection. Areas of research identified at this intersection include cyber-physical analysis of solar, wind, and distributed energy resources, microgrids, network evolution and observability, substation automation and self-healing, and probabilistic planning and operation methods

Dynamic Load Model Placement and Development with Case Study of Microgrid in Nome, Alaska

Dynamic modeling is key to the successful operation and reliability of electrical grids by evaluating transient stability. Developing dynamic load models and identifying where they are necessary is a challenging task as loads are an aggregation of individual devices that change throughout the year. This thesis investigates how to develop those load models and provides preliminary guidelines for where to prioritize placement of dynamic load models in the system. A case study in Nome, Alaska is performed on developing a dynamic load model for their microgrid. Electricity cost in Alaska's rural communities reaches up to five times higher than the national average. Theses rural communities' microgrids are powered primarily by diesel generators causing high electricity costs. This thesis examines the community of Nome, Alaska which has installed wind turbines to combat their dependency on diesel. Intermittent generation from the wind turbines can compromise the grid's resiliency and reliability. Dynamic modeling and reliability analysis are necessary to analyze possible solutions for stabilizing the grid. Adequate fidelity for the load model is necessary to perform dynamic simulations. A static ZIP load model and composite load model are created in this paper and are compared for improved modelling. Additionally, this load benchmark is used to evaluate the integration of an energy storage device to Nome's microgrid for improved transient stability. Using the composite load model in the microgrid model, a battery is modeled using the PSS E CBEST energy storage model, demonstrating the transient stability improvement provided by installing an energy storage device to the grid. Any microgrid utility, such as in Nome, Alaska, can adapt and use this load model development process depending on available computation resources and necessary data resolution for a particular generation and demand portfolio.Keywords: microgrid, dynamic modeling, reliability, power systems, dynamic load model, energy storag

Experimental Validation of a Diesel Genset Frequency Dynamics Model for Use in Remote Area Power Systems

Diesel generators (gensets) are often the lowest-cost electric generation for reliable supply in remote microgrids. The development of converter-dominated diesel-backed microgrids requires accurate dynamic modeling to ensure power quality and system stability. Dynamic response derived using original genset system models often does not match those observed in field experiments. This paper presents the experimental system identification of a frequency dynamics model for a 400 kVA diesel genset. The genset is perturbed via active power load changes and a linearized dynamics model is fit based on power and frequency measurements using moving horizon estimation (MHE). The method is first simulated using a detailed genset model developed in MATLAB/Simulink. The simulation model is then validated against the frequency response obtained from a real 400 kVA genset system at the Power System Integration (PSI) Lab at the University of Alaska Fairbanks (UAF). The simulation and experimental results had model errors of 3.17% and 11.65%, respectively. The resulting genset model can then be used in microgrid frequency dynamic studies, such as for the integration of renewable energy sources

Resilience in an Evolving Electrical Grid

Fundamental shifts in the structure and generation profile of electrical grids are occurring amidst increased demand for resilience. These two simultaneous trends create the need for new planning and operational practices for modern grids that account for the compounding uncertainties inherent in both resilience assessment and increasing contribution of variable inverter-based renewable energy sources. This work reviews the research work addressing the changing generation profile, state-of-the-art practices to address resilience, and research works at the intersection of these two topics in regards to electrical grids. The contribution of this work is to highlight the ongoing research in power system resilience and integration of variable inverter-based renewable energy sources in electrical grids, and to identify areas of current and further study at this intersection. Areas of research identified at this intersection include cyber-physical analysis of solar, wind, and distributed energy resources, microgrids, network evolution and observability, substation automation and self-healing, and probabilistic planning and operation methods

Review of Dynamic and Transient Modeling of Power Electronic Converters for Converter Dominated Power Systems

In response to national and international carbon reduction goals, renewable energy resources like photovoltaics (PV) and wind, and energy storage technologies like fuel-cells are being extensively integrated in electric grids. All these energy resources require power electronic converters (PECs) to interconnect to the electric grid. These PECs have different response characteristics to dynamic stability issues compared to conventional synchronous generators. As a result, the demand for validated models to study and control these stability issues of PECs has increased drastically. This paper provides a review of the existing PEC model types and their applicable uses. The paper provides a description of the suitable model types based on the relevant dynamic stability issues. Challenges and benefits of using the appropriate PEC model type for studying each type of stability issue are also presented