Showing papers by "Robert J. Thomas published in 2008"

Generating Random Topology Power Grids

Abstract: Simulation based on standard models is often used as part of the engineering design process to test theories and exercise new concepts before actually placing them into operation. In order to tackle the problem of likely widespread catastrophic failures of electric power grids, an autonomously reconfigurable power system will have to rely on wide-area communication systems, networked sensors, and restorative strategies for monitoring and control. Standard practice is to use simulation of a small number of certain historical test systems to test the efficacy of any proposed design. We believe this practice has shortcomings when examining new communication system ideas. In this paper we develop the means for producing power grids with scalable size and randomly generated topologies. These ensembles of networks can then be used as a statistical tool to study the scale of communication needs and the performance of the combined electric power control and communication networks. The topological and system features of the randomly generated power grids are compared with those of standard power system test models as a "sanity check" on the method.

Demand-Side Bidding Agents: Modeling and Simulation

Abstract: Problems such as price volatility have been observed in electric power markets. Demand-side participation is frequently offered as a potential solution by promising to increase market efficiency when hockey-stick-type offer curves are present. However, the individual end-consumer will surely value electricity differently, which makes demand-side participation difficult as a group and at a bus. In this paper demand is categorized into two groups: one that highly values reliability and one that does not. The two types are modeled separately and a new optimal bidding function is developed and tested based on this model.

Driving Results Through Social Networks: How Top Organizations Leverage Networks for Performance and Growth

Abstract: Preface. Acknowledgments. Introduction. Part One: Alignment. 1. Aligning Networks with Strategic Value Propositions. 2. Working Through Networks to Align Culture and Strategy. Part Two: Execution. 3. Managing Rapid Innovation Through Effective Networks. 4. Driving Financial Return Through Network Investments. 5. Delivering Results Through Process Networks. 6. Delivering Results Through Project-Based Networks. Part Three: Adaptation. 7. Driving Performance by Replicating High Performers' Networks. 8. Speeding Productivity in Newcomers and Avoiding Knowledge Drain. 9. The Road Ahead: Emerging Opportunities for the Network Perspective. About the Authors. Notes. Index.

The Influence of Generator Scheduling and Time-Varying Fault Rates on Voltage Sag Prediction

Abstract: This paper discusses the influence of generator scheduling and time-varying fault rates on the stochastic prediction of voltage sags. Typically, in the stochastic prediction of voltage sags, the annual expected sag frequencies (ESFs) at sensitive load points are calculated by assuming that the operating conditions and topology of the power system remain unchanged and fault rates of system components are constant throughout a year. In this paper, in order to obtain reasonable accuracy in predicting the annual ESFs at sensitive load points, the variation of fault rates due to adverse weather and the effect of generator scheduling are considered. The study was performed on the IEEE 30-bus test system. Two buses were randomly selected and the ESFs at the selected buses were calculated for different cases (i.e., with and without incorporation of time-varying fault rates and the operation schedule of generators in the system).

An advanced security constrained OPF that produces correct market-based pricing

Abstract: Security constrained optimal power flow programs are important tools for ensuring correct dispatch of supply while respecting the many constraints imposed by the delivery system. In addition to getting the dispatch right, locational prices must be calculated with equal precision in order to infuse market participants with the proper incentives for operation and investment. In this paper we discuss a co-optimization framework in which contingencies, ancillary services, and network constraints are correctly accounted for in determining both dispatch and price.

Nodal probabilistic production cost simulation considering transmission system unavailabilty

Abstract: A nodal probabilistic production cost simulation method is described for power system long-term expansion planning considering unavailability and delivery limitation constraints of the transmission system. This new nodal production cost simulation model includes capacity constraints and unavailabilities of generators as well as transmission lines. This simulation methodology comes from the nodal composite power system equivalent load duration curve (CMELDC), based on a new effective load model at load points developed by the authors. The nodal CMELDC can be obtained from convolution integral processing of the outage capacity probability distribution function of the fictitious generator and the original LDC. It is expected that the new simulation model based on the nodal CMELDC proposed here will provide solutions to many problems based on nodal and decentralised operation and control of electric power systems under a competition environment. The nodal CMELDC based on the new model at load points can extend application areas of nodal probabilistic production cost simulation, probabilistic congestion cost assessment, analytical outage cost assessment and nodal reliability evaluation and so on at load points. The characteristics and effectiveness of this new proposed methodology are illustrated by a small system case study using a network flow and enumeration method.