Robert J. Thomas

Bio: Robert J. Thomas is an academic researcher from Cornell University. The author has contributed to research in topics: Electric power system & Electricity market. The author has an hindex of 43, co-authored 178 publications receiving 11807 citations. Previous affiliations of Robert J. Thomas include University of California, Davis & National Renewable Energy Laboratory.

A method for identifying market power

Abstract: An ability to exercise market power by suppliers may significantly reduce market efficiency in restructured electricity markets. Many studies have been performed to develop an effective tool to identify market power based on indices. Most often it is rather difficult to use an index-based method for real-time analysis. This paper provides a method to identify market power that can be used in real time. The purpose is to analyze price-dispatch sensitivity to determine whether there is a generator or a subset of generators that have the ability to increase its own price profitably. Case studies performed on a modified IEEE 118-bus system are presented.

Power System State Measurements for Transient Control Augmentation Using Digital Techniques

Abstract: Any strategy, considered reasonable for the control of transient modes which occur as the result of a major disturbance in a large electric power system, will require fast and reasonably accurate measurements of at least two states per machine, namely, rotor speed deviation and torque angle. Since any control strategy will probably require an on-line digital computer for decision, computation, and execution, minimal computation time for the determination of state is imperative. Such a computer based technique along with the pertinent hardware for implementation is presented in this paper.

Towards Operational Validation: Mapping Power System Inputs to Operating Conditions

Abstract: Validation is a critical component in the development of synthetic models, which aims to convince a user that a model achieves its claims of realism. While users of power system test cases are primarily interested in operational results, which could be considered outputs, it is more convenient and feasible to control distributions of data inputs, both structural and otherwise. Validation metrics, are therefore generally focused on input rather than operation features. This paper investigates the link between input and output statistics in power system. Better understanding of this relationship allows validation to continue to focus largely on input statistics, while at the same time offering some assurance about operational behavior.

Designing a systems engineering educational program using academic/industry collaboration

Abstract: In concert with a fundamental precept in systems engineering, that system design should be driven by customer requirements, Cornell University is collaborating with industry in the development of a Master of Engineering program in Systems Engineering. This paper describes the underlying philosophy of Cornell's program, the collaborative process through which it has been developed, and the resulting curriculum, with a particular focus on the interaction between Cornell and Lockheed Martin Federal Systems (LMFS).

A method for classifying offer strategies observed in an electricity market

Abstract: The idea that large-scale generating units will operate at marginal cost when given the ability to offer their power for sale in a uniform price auction is at best wishful thinking. In fact, both real and experimental data show that the more uncertainty a supplier faces (e.g., load uncertainty, uncertainty of other suppliers, etc.), the more they will hedge their profits through higher than marginal cost offers and through withholding units if permitted. This makes predicting unit commitment and dispatch ahead of time difficult. This paper explores characteristics of software agents that were designed based on the outcome of human subject experiments on a uniform price auction with stochastic load. The agent behavior is compared to the behavior of the subjects. Both subject and agent behavior is classified based on the data. Differences and similarities are noted and explained. Based on the result of the simulation, a model was suggested to explain an offer submitted in deregulated markets based on double layer diffusion.

Random graphs

Abstract: We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

MATPOWER: Steady-State Operations, Planning, and Analysis Tools for Power Systems Research and Education

Abstract: MATPOWER is an open-source Matlab-based power system simulation package that provides a high-level set of power flow, optimal power flow (OPF), and other tools targeted toward researchers, educators, and students. The OPF architecture is designed to be extensible, making it easy to add user-defined variables, costs, and constraints to the standard OPF problem. This paper presents the details of the network modeling and problem formulations used by MATPOWER, including its extensible OPF architecture. This structure is used internally to implement several extensions to the standard OPF problem, including piece-wise linear cost functions, dispatchable loads, generator capability curves, and branch angle difference limits. Simulation results are presented for a number of test cases comparing the performance of several available OPF solvers and demonstrating MATPOWER's ability to solve large-scale AC and DC OPF problems.

Smart Grid — The New and Improved Power Grid: A Survey

Abstract: The Smart Grid, regarded as the next generation power grid, uses two-way flows of electricity and information to create a widely distributed automated energy delivery network. In this article, we survey the literature till 2011 on the enabling technologies for the Smart Grid. We explore three major systems, namely the smart infrastructure system, the smart management system, and the smart protection system. We also propose possible future directions in each system. colorred{Specifically, for the smart infrastructure system, we explore the smart energy subsystem, the smart information subsystem, and the smart communication subsystem.} For the smart management system, we explore various management objectives, such as improving energy efficiency, profiling demand, maximizing utility, reducing cost, and controlling emission. We also explore various management methods to achieve these objectives. For the smart protection system, we explore various failure protection mechanisms which improve the reliability of the Smart Grid, and explore the security and privacy issues in the Smart Grid.

Trends in Microgrid Control

Abstract: The increasing interest in integrating intermittent renewable energy sources into microgrids presents major challenges from the viewpoints of reliable operation and control. In this paper, the major issues and challenges in microgrid control are discussed, and a review of state-of-the-art control strategies and trends is presented; a general overview of the main control principles (e.g., droop control, model predictive control, multi-agent systems) is also included. The paper classifies microgrid control strategies into three levels: primary, secondary, and tertiary, where primary and secondary levels are associated with the operation of the microgrid itself, and tertiary level pertains to the coordinated operation of the microgrid and the host grid. Each control level is discussed in detail in view of the relevant existing technical literature.