Publications

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Conference Papers

Study Area Selection Tool to Enhance System Impact Analysis of Generator Interconnections

Published in 2025 IEEE Texas Power and Energy Conference (TPEC), 2025

This paper introduces a study area selection tool that identifies relevant network segments/facilities affected by interconnection of generators into a power grid. Case studies are shown using the actual Texas grid model where the tool captures essential network facilities to see the impact of generator integration at different Points of Interconnection (POI). The tool"s compatibility with existing power system analysis software make it valuable for reliable generator integration studies, minimizing iterative exchanges between generator owners and grid regulators. Read more

Recommended citation: S. Kunkolienkar, T.J. Overbye, G. Cabrera, H. Li, "Study Area Selection Tool to Enhance System Impact Analysis of Generator Interconnections", 2025 IEEE Texas Power and Energy Conference (TPEC), College Station, TX, February 2025.
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Visualizing Volt-Var Distributions in Large-Scale Electric Grid Models

Published in 2024 56th North American Power Symposium (NAPS), 2024

This paper analyzes the North American and syn-thetic power grid models by examining their voltage and reactive power output distributions. Histograms are used to visualize this difference. The North American grids, managed by various utilities and independent operators, exhibit considerable vari-ability in voltages and generator settings. In contrast, synthetic grids display uniform voltage levels and centralized control, indicating a simplified design approach. Statistical measures are presented to quantify these differences with the objective of making synthetic grids realistic. Read more

Recommended citation: Kunkolienkar, Sanjana, Jordan Cook, and Thomas J. Overbye. "Visualizing Volt-Var Distributions in Large-Scale Electric Grid Models." (2024).
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On the Existence of Dominant Inter-Area Oscillation Modes in the North American Eastern Interconnect Stability Simulations

Published in 57th Hawaii International Conference on Science Sciences (HICSS), 2024

This paper examines the extent to which distinct inter-area electromechanical modes exist in the North American Eastern Interconnect simulations. Electric grids oscillate, and these oscillations have often been described using the linear systems concept of modes. Furthermore, the inter-area behavior of large-scale grids, such as the North American Eastern Interconnect, is sometimes described using just a few dominant inter-area modes. This paper presents a simulation-based approach to determine the extent to which these modes exist. The approach is motivated using a 2000 bus synthetic grid, and then applied to an 87,000 bus model of the North American Eastern Interconnect (EI). The conclusion is while the EI has common patterns of oscillation, when considering a single operating point for the EI consistent distinct modes are not observed. Rather, the calculated apparent modes appear to be disturbance dependent. Read more

Recommended citation: Overbye, Thomas, Sanjana Kunkolienkar, Farnaz Safdarian, and Adam Birchfield. "On the Existence of Dominant Inter-Area Oscillation Modes in the North American Eastern Interconnect Stability Simulations." (2024).
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Developing a Dashboard To Enhance Visualization of Similar Historical Weather Patterns and Renewable Energy Generation

Published in 2024 IEEE Workshop on Energy Data Visualization (EnergyVis), 2024

This paper presents a dashboard to find and compare days with similar weather patterns within an 80-year historical weather dataset. The dashboard facilitates the analysis of weather patterns and their impact on renewable energy generation by defining and identifying similar weather days. Users are given the flexibility to select the metric for determining similarity, which includes a combination of temperature, dew point, wind speed, Global Horizontal Irradiance (GHI), Direct Horizontal Irradiance (DHI), and cloud cover. The region for this work is limited to Texas. The dashboard then generates an output that compares the selected weather metrics and the corresponding renewable generation outputs. Read more

Recommended citation: Kunkolienkar, Sanjana, Nikola Slavchev, Farnaz Safdarian, and Thomas Overbye. "Developing a Dashboard to Enhance Visualization of Similar Historical Weather Patterns and Renewable Energy Generation."
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A Description of the Texas A&M University Electric Grid Test Case Repository for Power System Studies

Published in 2023 IEEE Texas Power and Energy Conference (TPEC), 2024

A repository of diverse electric grid test cases, varying in size and characteristics, has been developed for application in power system studies. The purpose of this repository is to provide public access to realistic electric grid models of varying sizes to help facilitate research and education. This repository is regularly updated with new test cases or modifications of existing ones as a result of continuing research. This paper outlines the necessity for this repository, details the electric grids it contains, and provides explanations for the types of cases, highlighting their relevance to different applications. Read more

Recommended citation: Kunkolienkar, Sanjana, Farnaz Safdarian, Jonathan Snodgrass, Adam Birchfield, and Thomas Overbye. "A Description of the Texas A&M University Electric Grid Test Case Repository for Power System Studies." (2024).
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Quantification of Area Sparsity for Large-Scale Electric Grids

Published in 2023 Kansas Power and Energy Conference(KPEC 2023), 2023

This paper quantifies the likelihood of two substations being connected based on the topology to improve and build more realistic synthetic grids with evaluating the idea that in North American power grids, two substations are more likely to be connected if they belong to the same area than to different areas. Statistical methods are used to identify and visualize the topological differences between real and synthetic grids and how areas to which a substation belongs influence how likely the substations are to be connected. This paper defines a new term, Area Sparsity, to quantity the relationship between substation connectedness and highlights the need to explicitly incorporate the power grid areas into creating more realistic synthetic grids. The results show that the actual grids are more connected in the same area; however, this is not the case for the existing large-scale synthetic grids. Read more

Recommended citation: Kunkolienkar, Sanjana, Farnaz Safdarian, Jonathan Snodgrass, and Thomas Overbye. "Quantification of Area Sparsity in Large-Scale Electric Grids." (2023).
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Pedagogical Application of Visualization and Eye Tracking For Electrical Grid Management

Published in 2023 International Conference on Applied Human Factors and Ergonomics, 2023

Visualizations have been proven to be a beneficial pedagogical tool used in teaching complex concepts to students. Its application as an effective active learning method has been implemented in multiple sectors, such as arts, science, engineering, and social science. In this paper, we present a pilot study exploring the use of visualizations to facilitate students comprehension of electrical grid management principles in an active learning process. The methods for conducting the eye-tracking study are presented here, with the results available at the meeting. These results will illustrate how students engage with visualizations as part of the learning process. This study is part of a series of studies focused on examining how methods from human factors and ergonomics can be leveraged for evaluating electrical grid management control rooms. For instance, in a previous pilot study, eye tracking was used to evaluate situation awareness in electrical grid control rooms using visualizations. A comparison of the eye tracking results to the Cognitive Task Analysis (CTA), revealed four SA demons: misplaced salience, data overload, errant mental models, and attentional narrowing. Read more

Recommended citation: Fru, Felix Azenwi, et. al "Pedagogical Application of Visualization and Eye Tracking For Electrical Grid Management." Training, Education, and Learning Sciences 109, no. 109 (2023).
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On the Existence of Distinct Inter-Area Electro-Mechanical Modes in North American Electric Grids

Published in 2023 Kansas Power and Energy Conference(KPEC 2023), 2023

This paper examines the extent to which distinct inter-area electromechanical modes exist in large-scale electric grids. Electric grids oscillate, and these oscillations have often been described using the linear systems concept of modes. However, electric grids are nonlinear systems, and are becoming increasingly nonlinear with the growth of inverter-based controls, deadbands, and other devices that often operate at their limits. Hence adequate linearizations may no longer exist, calling into question the extent to which distinct modes exist. For a mode to exist at an operating point its frequency, damping and shape must be independent of the disturbance used to excite it. The paper shows for one synthetic and two actual models of North American electric grids that these criteria are not always met, particularly for the largest electric grids. Read more

Recommended citation: Overbye, Thomas J., and Sanjana Kunkolienkar. "On the Existence of Distinct Inter-Area Electro-Mechanical Modes in North American Electric Grids." (2023).
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Creating Active and Reactive Power Reserve Zones for Large-Scale Electric Grids

Published in 2023 Kansas Power and Energy Conference(KPEC 2023), 2023

This paper proposes a strategy to partition large electrical grids into active power and reactive power reserve zones by applying a clustering algorithm to the Laplacian of the power system Jacobian matrix. This strategy is applied to two large synthetic cases with around 7k and 24k buses, and the results are provided. This partitioning further facilitates determining required real power and reactive power reserve types for each zone. Read more

Recommended citation: Sanjana Kunkolienkar, Farnaz Safdarian, Jonathan Snodgrass, and Thomas J. Overbye. "Creating Active and Reactive Power Reserve Zones for Large-Scale Electric Grids." (2023).
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On the Sensitivity of Ring-Down Observed Inter-Area Modes in Large-Scale Electric Grids Using a Simulation Approach

Published in 2022 IEEE Power and Energy Conference at Illinois (PECI), 2022

This paper presents results on the sensitivity of the inter-area electromechanical modes obtained by ring-down, measurement-based modal analysis for large-scale electric grids. The paper utilizes the Iterative Matrix Pencil Method (IMP) to determine the most significant electro-mechanical modes and their associated mode shapes after the system has been perturbed by generator or load outage contingencies. The paper shows that the resultant values can be dependent on both the applied contingency and the set of signals used in the IMP with this sensitivity due at least in part to the system nonlinearities. The techniques are demonstrated using three synthetic grids ranging in size between 2000 and 70,000 buses. Visualization methods are used to show the mode shapes and compare and contrast how modes manifest themselves on the grid. Read more

Recommended citation: Trinh, W. (2022). "On the Sensitivity of Ring-Down Observed Inter-Area Modes in Large-Scale Electric Grids Using a Simulation Approach" 2022 IEEE Power and Energy Conference at Illinois (PECI). 1(2).
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Case Study of Enhancing the Matpower Polish Electric Grid

Published in 2022 IEEE Texas Power and Energy Conference (TPEC), 2022

The MATPOWER Polish systems are several power system test cases that are created using the real power system of Poland circa 2000. However, dynamic model parameters and geographic coordinates were not provided with the initial cases in MATPOWER. To improve the Polish test systems, this paper describes the process of converting the Polish systems included with MATPOWER to the PowerWorld format, assigning geographic coordinates to the 400 kV and 220 kV high voltage networks and adding dynamic models. Additionally, several categories of power system metrics were analyzed for the MATPOWER Polish systems, and the results compared with the corresponding metrics from the United States power systems. Read more

Recommended citation: Snodgrass, J. (2022). "Case Study of Enhancing the Matpower Polish Electric Grid" 2022 IEEE Texas Power and Energy Conference (TPEC). 1(1).
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