Showing papers by "Thomas J. Overbye published in 2001"

Visualizing the electric grid

Abstract: In the new world of competition, power traders, grid managers, public service boards, and the public itself all need to take in what's happening at a glance. Visualization software enables viewers to interpret the data more rapidly and more accurately than ever before. This kind of software will become still more useful, even indispensable, as electricity grids are integrated over ever-larger areas, as transmission and generation become competitive markets, and as transactions grow in number and complexity. Concepts like power flow, loop flow, and reactive power, which once mattered only to the engineers directly involved in grid operations, now must be made intuitive. This is because they must be communicated to public service commissions and the consumer-voters to whom such boards are answerable. In short, whether the client/user is a power marketer, a grid operator or manager, a public authority, or a member of the public, power system visualization tools can aid their comprehension by lifting the truly significant above background noise. Such tools can expedite decision-making for congestion management, power trading, market organization, and investment planning for the long term.

Extended factors for linear contingency analysis

Abstract: This paper presents preliminary results on three new tools to quickly assess the impact of line outages and reclosure on generators. The first deals with the estimation of the angle across the breaker of an opened line. The second deals with the estimation of the immediate currents that arise in generators in response to a line outage. The third deals with the estimation of the immediate currents that arise in generators in response to a line closure. The first would be used to determine if a reclosing relay might block a reclosure. The second would be used to determine if a line outage might damage a generator. The third would be used to determine if the override of a blocked reclosure might be allowable. The concepts are illustrated on test cases.

Analysis and visualization of market power in electric power systems

Abstract: This paper discusses the assessment and visualization of market power in bulk electricity markets, with the explicit consideration of transmission system constraints. In general, market power is the ability of a particular seller or group of sellers to maintain prices profitably above competitive levels for a significant period of time. When an entity has and exercises market power, it ceases to be a price-taker and becomes a price-maker. The restructuring of the electric industry in many parts of the world has encouraged competitive markets with the objective of reaping the benefits of lower prices and innovation that competition can provide. Such benefits are not attainable when a player utilizing the electric transmission system may exert market power. This paper describes the procedures for analyzing and visualizing such situations.

Human factors analysis of power system visualizations

Abstract: This paper describes an experimental approach to formally testing the usability of different power system visualizations. In particular, the ability of participants to assess and correct power system voltage problems was tested. Participants were divided into three groups: the first group only saw tabular data, the second group one-line data, while the third group saw one-line data and a color voltage contour. The time to acknowledge the voltage violations and the time to correct the violations were assessed.

Visualizing the interaction between the transmission system and power markets

Abstract: Power system analysis software is undergoing a rapid evolution to meet new data visualization challenges. This paper addresses several methods of visualization for helping users extract useful information associated with grid operation from the tidal wave of power system data. These techniques include animation of power system flow values, contouring of bus and transmission line flow values and 3D visualization.

Strategic equilibria in centralized electricity markets

Abstract: The introduction of competition in electricity markets has given rise to the problem of strategic bidding by rational market participants (or players) in pursuit of individual profit (or welfare) maximization. Given the simultaneous action of all players, Nash equilibria are the solutions in the bidding space that simultaneously satisfy their individual objectives. The paper addresses the problem of finding Nash equilibria in a centralized competitive electricity market (PoolCo model) in which we assume that the players have reasonable estimates about all the other players' utility functions. In addition, we assume that a central decision maker-the independent grid operator or IGO-dispatches the market using an OPF tool that accepts as its inputs the bids and offers freely submitted by the participants. The paper shows how to search for multiple equilibria in a systematic manner if we make specific assumptions for the grid model and for the utility functions.

Transmission impacts and visualization of new generation

Abstract: With deregulation in the electric industry the process of siting new generation has changed dramatically. In the previous vertically integrated utility paradigm, the local utility could bundle the cost of new transmission with the costs associated with adding generation. With deregulation, independent generators usually wish to site at locations in which their new generation will not cause any new overloads in the transmission grid. This paper describes a process for systematically determining the impact new generation will have on the transmission system. Emphasis is also placed on the visualization of these transmission system impacts.

Optimization and visualization of the north american eastern interconnect power market

Abstract: This paper uses a first generation OPF model of the Eastern Interconnect to gauge the potential benefits deriving from RTOs in an ideal world. So long as the lines and generators are operating as planned, there is sufficient low cost capacity to keep peak demand prices in the Eastern Interconnect below $50 MWH. Under a reasonable approximation of ideal conditions, a repeat of San Diego's experience is unlikely. Unfortunately, a few downed lines or generator outages can greatly impact local prices even with unrestricted trade.

Transmission impacts and visualization of new generation

Abstract: With deregulation in the electric industry the process of siting new generation has changed dramatically. In the previous vertically integrated utility paradigm, the local utility could bundle the cost of new transmission with the costs associated with adding generation. With deregulation, independent generators usually wish to site at locations in which their new generation will not cause any new overloads in the transmission grid. This paper describes a process for systematically determining the impact new generation will have on the transmission system. Emphasis is also placed on the visualization of these transmission system impacts.