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2005 Publications

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05-01Reducing the Risk of Major Blackouts Through Improved Power System Visualization
Many blackouts occur with time scales that would permit emergency control by the operators. However, in order to perform this control the operators need to quickly know the state of system and implement timely, corrective control actions. This paper describes several visualization techniques that can be used to provide this information. Techniques discussed include the use of dynamically sized pie charts on transmission lines, the use of transmission line flow animation, and the use of contouring.
Submitted to 15th Power System Computation Conference (PSCC), August 2005, Liège, Belgium. Uploaded: Jan. 17, 2005.		Thomas J. Overbye, Douglas A. Wiegmann1/17/2005593.5kPDF
05-02Phasor Measurement Unit Data in Power System State Estimation
This report deals with the placement of phasor measurement units (PMUs) based on the improvement in error in the estimate of the voltage phase angles in power systems. The present technology measures voltage, current, and real and reactive power for determining the operating condition of the electric network. This technology cannot measure voltage phase angle directly. Thus, voltage phase angles must be found by state estimation. This research examined two possible methods for incorporating phasor measurement units into present state estimation methods. The two principal state estimation methods considered are: 1) using weighted least squares with significant weight on the PMU measurements; and 2) eliminating the equations associated with the voltage phase angle measurements made by the PMU. The PMU measurements would be done using global positioning system (GPS) technology to measure voltage phase angles; this measurement would be very accurate. The test bed for the state estimation methodology assessment is the Institute Electrical and Electronics Engineering (IEEE) 14 bus system. In this study, the IEEE 14 bus system is fully observable by supervisory control and data acquisition (SCADA) devices. The incorporation of PMU measurements into the system increases the accuracy of the voltage phase angle estimates. The cases considered examine the location of the PMUs based on decreasing the error in the estimate of voltage phase angle. The work includes an examination of the impact of noise on the location of the PMUs. Also included in this work is the relationship between the number of PMUs installed and the error in the voltage phase angle estimates. A goal of this work is to show the gains that can be attained by PMUs. Intermediate Project Report for "Enhanced State Estimators" (S-22). Uploaded: 11/27/05. Members viewing only.		Mark Rice and Gerald T. Heydt4/27/2005LinkURL
05-03Technical Considerations for Broadband Powerline (BPL) Communication
The use of the electric power transmission and distribution system as a transmission medium for broadband communications is considered. It is found that there are three significant technical hurdles to be overcome before successful implementation of such systems can be accomplished. The first is the relatively high attenuation rate due to discontinuities such as taps, transformers and other devices connected to the system. The second is the relatively high background noise on power lines. The third is government regulated limitation on transmitted power for the unlicensed systems that use the power system as a communications medium.
Appears in the Proceedings of the 2005 Zurich Symposium on Electromagnetic Compatibility, Zurich, Switzerland, February 2005. Uploaded: February 7, 2005.		2/7/2005157.5kPDF
05-04On-Line Transient Stability Assessment Scoping Study
This project’s objectives were to review the state of art in on-line transient stability assessment; evaluate promising new technologies; and identify technical and computational requirements for calculating transient stability limits and corrective and preventive control strategies for operating situations that are transiently insecure. Six on-line transient stability package vendors were identified by conducting a literature survey. A detailed questionnaire which addressed several pertinent issues relating to on-line transient stability assessment was prepared. All six vendors responded to the questionnaire. The responses received were carefully analyzed. This analysis provided a detailed overview of the capabilities of available tools, performance metrics, modeling features, and protective and corrective control measures. An elaborate questionnaire was then prepared and sent to all PSERC member companies. This questionnaire addressed specific needs in terms of required features, preferred performance, and control capabilities. A detailed analysis of the responses received provided a clear picture of the desired features and performance specifications of an on-line transient stability assessment tool. A comparison of the analysis conducted on the vendor responses and the PSERC member company responses identified areas and topics that needed further development and research. This information will be useful in soliciting new research proposals and providing vendors a guide to the features that need to developed and implemented. A literature survey was also conducted on new analytical developments in on-line transient stability analysis. Based on this review, novel concepts based on quadratized models for power system components were explored. Final Report for the PSERC project "On-Line Transient Stability Assessment (S-21)." Received: February 2,2005. Uploaded: February 10, 2005. Members viewing only.		Vijay Vittal, Project Leader5/10/2005LinkURL
05-05Cournot Equilibria in Two-Settlement Electricity Markets with System Contingencies
We study Nash equilibrium in two-settlement competitive electricity markets with horizontal market power, flow congestion, demand uncertainties and probabilistic system contingencies. The equilibrium is formulated as a stochastic Equilibrium Problem with Equilibrium Constraints (EPEC) in which each firm solves a stochastic Mathematical Program with Equilibrium Constraints (MPEC). We assume a no-arbitrage relationship between the forward prices and the spot prices. We find that, with two settlements, the generation firms have incentives to commit forward contracts, which increases social surplus and decreases spot energy prices. Furthermore, these effects are amplified when there are more firms in the markets.
Received and Uploaded: February 14, 2005.		Jian Yao, Shmuel S. Oren, and Ilan Adler2/14/2005157.3kPDF
05-06A Criticality Approach to Monitoring Cascading Failure Risk and Failure Propagation in Transmission Systems
We consider the risk of cascading failure of electric power transmission systems as overall loading is increased. There is evidence from both abstract and power systems models of cascading failure that there is a critical loading at which the risk of cascading failure sharply increases. Moreover, as expected in a phase transition, at the critical loading there is a power tail in the probability distribution of blackout size. (This power tail is consistent with the empirical distribution of North American blackout sizes.) The importance of the critical loading is that it gives a reference point for determining the risk of cascading failure. Indeed the risk of cascading failure can be quantified and monitored by finding the closeness to the critical loading. This paper suggests and outlines ways of detecting the closeness to criticality from data produced from a generic blackout model. The increasing expected blackout size at criticality can be detected by computing expected blackout size at various loadings. Another approach uses branching process models of cascading failure to interpret the closeness to the critical loading in terms of a failure propagation parameter lambda. We suggest a statistic for lambda that could be applied before saturation occurs. The paper concludes with suggestions for a wider research agenda for measuring the closeness to criticality of a fixed power transmission network and for studying the complex dynamics governing the slow evolution of a transmission network.
Uploaded: February 14, 2005		Ian Dobson, Ben Carreras, and David Newman2/14/2005361.3kPDF
05-07The Impact of Various Upgrade Strategies on the Long-Term Dynamics and Robustness of the Transmission Grid
We use the OPA global complex systems model of the power transmission system to investigate the effect of a series of different network upgrade scenarios on the long time dynamics and the probability of large cascading failures. The OPA model represents the power grid at the level of DC load flow and LP generation dispatch and represents blackouts caused by randomly triggered cascading line outages and overloads. This model represents the long-term, slow evolution of the transmission grid by incorporating the effects of increasing demand and engineering responses to blackouts such as upgrading transmission lines and generators. We examine the effect of increased component reliability on the long-term risks, the effect of changing operational margins and the effect of redundancy on those same long-term risks. The general result is that while increased reliability of the components decreases the probability of small blackouts, depending on the implementation, it actually can increase the probability of large blackouts. When we instead increase some types of redundancy of the system there is an overall decrease in the large blackouts with a concomitant increase of the smallest blackouts. As some of these results are counter intuitive these studies suggest that care must be taken when making what seem to be logical upgrade decisions.
Uploaded: February 14, 2005		David Newman, Ben Carreras, Vickie Lynch, and Ian Dobson2/14/2005492.4kPDF
05-08Electricity Derivatives and Risk Management
Electricity spot prices in the emerging power markets are volatile, a consequence of the unique physical attributes of electricity production and distribution. Uncontrolled exposure to market price risks can lead to devastating consequences for market participants in the restructured electricity industry. Lessons learned from the financial markets suggest that financial derivatives, when well understood and properly utilized, are beneficial to the sharing and controlling of undesired risks through properly structured hedging strategies. We review different types of electricity financial instruments and the general methodology for utilizing and pricing such instruments. In particular, we highlight the roles of these electricity derivatives in mitigating market risks and structuring hedging strategies for generators, load serving entities, and power marketers in various risk management applications. Finally, we conclude by pointing out the existing challenges in current electricity markets for increasing the breadth, liquidity and use of electricity derivatives for achieving economic efficiency.
Working Paper. Uploaded: February 24, 2005		Shi-Jie Deng and Shmuel Oren2/24/200581.3kPDF
05-09The Inherent Inefficiency of Simultaneously Feasible Financial Transmission Rights Auctions
Empirical evidence shows that the clearing prices for point-to-point congestion revenue rights, also known as financial transmission rights (FTRs), resulting from centralized auctions conducted by Independent System Operators differ significantly and systematically from the realized congestion revenues that determine the accrued payoffs of these rights. The question addressed by this paper is whether such deviations are due to price discovery errors which will eventually vanish or due to inherent inefficiencies in the auction structure. We show that even with perfect foresight of average congestion rents the clearing prices for the FTRs depend on the bid quantity and therefore may not be priced correctly in the financial transmission right (FTR) auction. In particular, we prove that quantity limits on the FTR bids may cause the auction clearing prices to differ from the bid prices. This phenomenon which is inherent in the theoretical properties of the optimization algorithm used to clear the auction, is further illustrated through numerical simulations with test systems. We conclude that price discovery alone would not remedy the discrepancy between the auction prices and the realized values of the FTRs. Secondary markets or frequent reconfiguration auctions are necessary in order to achieve such convergence.
Working Paper. Uploaded: February 24, 2005.		Shi-Jie Deng, Shmuel Oren, and Sakis Meliopoulos2/24/2005119.5kPDF
05-10Pricing and Hedging Electricity Supply Contracts: a Case with Tolling Agreements
Customized electric power contracts catering to specific business and risk management needs have gained increasing popularity among large energy buyers in the restructured electricity industry. A tolling agreement (or, tolling contact) is one such example in which a contract buyer reserves the right to take the output of an underlying electricity generation asset by paying a predetermined premium to the asset owner. We propose a real options approach to value a tolling contract incorporating operational characteristics of the generation asset and contractual constraints. Dynamic programming and value function approximation by Monte Carlo based least-squares regression are employed to solve the valuation problem. The effects of different electricity price assumptions on the valuation of tolling contracts are examined. Based on the valuation model, we also propose a heuristic scheme for hedging tolling contracts and demonstrate the validity of the hedging scheme through numerical examples.
Working Paper. Uploaded: February 24, 2005		Shi-Jie Deng and Zhendong Xia3/25/2005475.4kPDF
05-11Hedging Quantity Risks with Standard Power Options in a Competitive Wholesale Electricity Market
This paper addresses quantity risk in the electricity market, and explores several ways of managing such risk. The paper also addresses the hedging problem of a load serving entity, which provides electricity service at a regulated price in electricity markets with price and quan- tity risk. Exploiting the correlation between consumption volume and spot price of electricity, an optimal zero-cost hedging function char- acterized by payoff as a function of spot price is derived. It is then illustrated how such a hedging strategy can be implemented through a portfolio of forward contracts and call and put options.
Uploaded: March 7, 2005		Yumi Oum and Shmuel Oren3/7/2005421.9kPDF
05-12CERTS Proves that Two Grids are Better than One
Connecting generators to the grid is technically involved and expensive, so much so that the price tag and impact assessment can be deal-killers. Resulting interconnection charges, notes Robert Lasseter, professor emeritus of electrical engineering at the University of Wisconsin, "can sometimes run as much as the distributed generation [DG]" itself, and this is obviously prohibitive. Lasseter is part of a major initiative that's now working hard to solve and perhaps forever alter dramatically the connective relationship between DG and utilities. One primary focus, potentially the most revolutionary for DG, is the group's emerging technology and design concept for electrical microgrids.
Distributed Energy: The Journal for Onsite Power Solutions; March/April 2005.		David Engle3/30/2005LinkURL
05-13Comprehensive Power System Reliability Assessment
This project advances the state of the art in reliability assessment of electric power systems. The developed techniques enable probabilistic risk assessment. Risk issues have become of utmost importance as market forces are introduced into the power industry. The project’s objective is to provide an integrated approach to reliability assessment addressing the issues of component reliability as well as system reliability. The developed methodology uses sensitivity analysis to identify components that limit system reliability. An added feature of the methodology is a probabilistic approach for estimating available transfer capability. The reliability analysis methods can provide reliability indices at a customer site or at any system bus. Probability, frequency and duration indices are computed using methods based on a Markov state space approach. Examples are: (a) probability of customer interruption, (b) frequency of customer interruption, and (c) duration of customer interruption. Draft Final Project Report for the PSERC Project "Comprehensive Power System Reliability Assessment" (S-13). Initial Draft Received: Nov. 1, 2004. Final Report Uploaded: April 1, 2005. Member viewing only.		Sakis Meliopoulos, Project Leader4/1/2005LinkURL
05-14Distribution System Electromagnetic Modeling and Design for Enhanced Power Quality
A new, comprehensive methodology for power quality assessment has been developed in this project. A key innovation is the use of physically-based models of electric power system components, coupled with Monte Carlo simulation to conduct the assessment. The models describe components by their physical characteristics and arrangements. From the physical descriptions, electrical models are derived while all constituent parts are explicitly represented. For example, steel conduit, neutral conductors, phase conductors (among other physical features) are explicitly modeled for a steel conduit enclosed circuit. The overall power quality assessment model is efficiently solved in two steps. In the first step, the model is quadratized; that is, a nonlinear model of a system component is converted into a set of second order equations with the introduction of appropriate transformations. Then, in the second step, the quadratized model is solved with a Newton-type algorithm. The resulting analysis method is robust and efficient. This methodology can be used in time and frequency domain analyses. This is the final project report for project T-12. Draft received: April 4, 2005. Uploaded: April 30, 2005. Member viewing only.		Sakis Meliopoulos, Project Leader5/10/2005LinkURL
05-15A Study of Synchronized Sampling Based Fault Location Algorithm Performance under Power Swing and Out-of-step Conditions
Relay misoperations play an important role in cascading blackouts. Power swing and out-of-step conditions caused by large disturbances in the system may result in relay misoperations. This effect is analyzed and simulated in this paper. Synchronized sampling based fault location (SSFL) algorithm was proposed as part of an advanced fault analysis tool to give precise fault information and verify relay judgments. This paper further analyzes the algorithm under power swing and out-of-step conditions and tests it by both static and dynamic scenarios generated in ATP. The test results indicate that SSFL algorithm performs better than distance relay under power swing and out-of-step conditions and can be used as a robust fault analysis tool for practical use. Appears in Proceedings of PowerTech 2005, St. Petersburg, Russia, June 2005. Paper for the PSERC project Detection, Prevention and Mitigation of Cascading Events (S-19). Uploaded May 6, 2005.		Nan Zhang, Mladen Kezunovic5/10/2005288.6kPDF
05-16Coordinating Fuzzy ART Neural Networks to Improve Transmission Line Fault Detection and Classification
This paper demonstrates several uses of Adaptive Resonance Theory (ART) based neural network (NN) algorithm combined with Fuzzy K-NN decision rule for fault detection and classification on transmission lines. To deal with the large input data set covering system-wide fault scenarios and improve the overall accuracy, three Fuzzy ART neural networks are proposed and coordinated for different tasks. The performance of improved scheme is compared with the previous development based on the simulation using a typical power system model. The speed and accuracy of detecting continuous signals during the fault is also evaluated. Simulation results confirm the improvement benefits when compared with the previous implementation. Appears in Proceeding of IEEE PES General Meeting, San Francisco, June 2005. Paper for PSERC project Detection, Prevention and Mitigation of Cascading Events (S-19). Uploaded May 6, 2005.		Nan Zhang and Mladen Kezunovic5/10/2005287.7kPDF
05-17Static Analysis of Vulnerability and Security Margin of the Power System
This paper introduces new concepts for evaluation of the power system steady state operations, namely the Vulnerability Index (VI) and Margin Index (MI). They provide quantitative vulnerability and security margin information about generation, transmission, load conditions and then the whole system. System operators can assess the system security and vulnerability information using the margin and vulnerability indices. Therefore, they can take some preventive and emergency control steps to keep the system operating at the secure level. Accepted by 2005 IEEE PES T&D Conference, New Orleans, Oct. 2005. Prepared for PSERC project Detection, Prevention and Mitigation of Cascading Events (S-19). Uploaded May 6, 2005.		Hongbiao Song and Mladen Kezunovic5/10/2005102.6kPDF
05-18Improving Real-time Fault Analysis and Validating Relay Operations to Prevent or Mitigate Cascading Blackouts
This paper proposes a new strategy at the local (substation) level, aimed at preventing or mitigating the cascading blackouts that involve relay misoperations or inadequate local diagnostic support. The strategy consists of an advanced real-time tool that combines neural network based fault detection and classification (NNFDC) algorithm and synchronized sampling based fault location (SSFL) algorithm with a relay monitoring tool using event tree analysis (ETA). The fault analysis tool provides a reference for conventional distance relay with its better performance and the relay monitoring tool provides detailed local information about the disturbances. The idea of the entire strategy is to meet several NERC recommendations to prevent blackouts using wide area protection and control. IEEE PES T&D Conference, New Orleans, Oct. 2005. Paper for the PSERC project Detection, Prevention and Mitigation of Cascading Events (S-19). Uploaded May 6, 2005.		Nan Zhang, Mladen Kezunovic5/10/2005294.5kPDF
05-19Model Reduction in Power Systems Using Krylov Subspace Methods
This paper describes the use of Krylov subspace methods in the model reduction of power systems. Additionally, a connection between the Krylov subspace model reduction and coherency in power systems is proposed, aiming at retaining some physical relationship between the reduced and the original system.
IEEE Transactions on Power Systems, Vol. 20, No. 2, May 2005, 888-894. Uploaded May 12, 2005.		Dimitrios Chaniotis and M. A. Pai5/12/2005350.2kPDF
05-20Optimal Placement and Utilization of Phasor Measurements for State Estimation
This paper presents a procedure by which new PMU locations can be systematically determined in order to render an observable system. The procedure is then extended to account for cases of loss of a single phasor measurement unit (PMU). Buses with zero and nonzero injections, and branches with power flow measurements are also accounted for in this generalized procedure. Several cases involving different power system and measurement configurations are presented where introducing few extra strategically placed PMUs minimizes vulnerability of the measurement system against the loss of single PMUs. The paper also develops a linear estimator based on strictly PMU measurements and investigates the computational performance as well as the bad data processing problem. Detection and identification of PMU failures are demonstrated via simulations.
Uploaded May 12, 2005.		Xu Bei, Yeo Jun Yoon and Ali Abur5/12/200581.3kPDF
05-21Automatic Simulation Of IED Measurements For Substation Data Integration Studies
With the deregulation and restructuring of utility industry, many substation automation applications are being developed. These applications need to be tested for their accuracy and reliability. In cases when physical testing in substations is difficult, it is desirable to have a software tool to simulate the Intelligent Electronic Device (IED) measurements in substations. This paper presents the design of such a software application that can be used to generate substation IED measurements in fault and/or switching scenarios. The software structure and input/output interfaces are provided, as well as their implementation details. Two examples of simulation results are included in the paper. This software application serves as a handy tool for substation automation related studies. This paper was accepted by 2005 PES General Meeting. It was supported in part by PSerc Project T-17: “Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring”.		Yang Wu and Mladen Kezunovic5/15/2005405.6kPDF
05-22Insulators for Cold Urban Areas: The Problem of Road Salt
In order to permit safe passage for pedestrians and vehicles during winter months, the sidewalks and roads in urban areas are salted at regular intervals. The goal is to prevent ice formation on these surfaces and to deice the surfaces as quickly as possible. Utilities serving the metropolitan areas of Denver, Chicago and others are complaining of increased incidences of wood pole fires and insulator flashovers during the winter months. Whether this is solely due to the deicing liquid chemicals is hard to say at this stage due to lack of comprehensive scientific data. The research objectives are: (1) to determine the pollution severity caused by the road salt in terms of conventional ESDD (equivalent salt deposit density), (2) to determine the cleaning action of natural agents like rain and wind, and (3) explore new methods of characterizing contamination severity and (4) use all of the above information to predict if and when utilities to engage in washing programs to maintain continuity of power delivery.		Ravi Gorur and Sreeram Venkataraman5/15/2005140.9kPDF
05-23Predicting Contamination Flashover of Insulators: Successes and Shortcomings of Tests and Simulations
Perhaps no single area of insulator behavior has fascinated researchers more so than predicting flashover under contaminated conditions. For traditional porcelain and glass insulators, there is a large body of literature published that includes both theoretical models and experimental tests to simulate this interesting and practically important aspect of insulator performance. Yet there still some critical gaps in the understanding of this complex problem. This article summarizes the state of the art for porcelain and glass insulators, which are still the workhorses of industry.
Published in the Insulator News and Market Report in Feb. 2005, Q1, issue. Uploaded May 12, 2005		Ravi S. Gorur and S. Venkataraman5/15/2005196.2kPDF
05-24Quantification of Corona Discharges on Nonceramic Insulators
This paper attempts to establish a correlation of the visual images of corona obtained from a camera with discharge magnitude measured with conventional partial discharge equipment. A linear relationship is shown between the transformed image parameters and the discharge magnitude, thereby providing a means for quantifying corona observations made during routine maintenance inspections of insulators from ground. Different insulator designs using silicone rubber (SIR) and ethylene propylene diamene monomer (EPDM) housings were examined. The effect of fog has been examined by performing experiments inside a fog chamber. It is shown that this information can be used along with the corona degradation characteristics of housing materials to identify discharge patterns that can pose problems to the integrity of the insulator.
Uploade May 12, 2005.		B. Pinnangudi, R. S. Gorur, and A. J. Kroese5/15/2005783.0kPDF
05-25Requirements Specification for and Evaluation of an Automated Substation Monitoring System
This paper presents functional requirements for the Automated Analysis Substation System (AASS) implemented at Texas A&M University, aimed at monitoring functions using data measured by multiple substation Intelligent Electronic Devices (IEDs). The implemented system is based on a new concept of data integration and information exchange where the data from several substation IEDs is integrated and information needed by various groups of utility users is extracted. Once fully implemented, this solution will provide both local and remote functions allowing further benefits to be drawn from the concept of substation data integration and information exchange.
Uploaded May 12, 2005		Mladen Kezunovic and G. Latisko5/15/2005298.8kPDF
05-26Automated Analysis of Digital Relay Data Based on Expert System
Modern digital protective relays generate various files and reports which contain abundant data regarding fault disturbances and protection system operation. This paper presents an expert system based application for automated analysis of digital relay data. In this application, forward chaining reasoning is used to predict expected protection operation while backward chaining reasoning is employed to validate and diagnosis of actual protection operation. An EMTP/C++ based digital relay model with capability of insertion of user-defined errors and generation of files and reports is developed. The analysis capability of this application is tested using the relay model. This paper was accepted by PowerTech 2005 Conference, St. Petersburg, Russia, June 2005.
The work was supported by PSerc Project T-17 "Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring". Uploaded May 14, 2005.		Xu Luo and Mladen Kezunovic5/15/2005546.6kPDF
05-27Automated Analysis of Protective Relay Data
Validation and diagnosis of relay operation is very important to protection engineers in fault analysis. This paper presents development of an expert system based automated analysis solution, which performs validation and diagnosis of digital protective relay operation in great detail by analyzing data contained in various relay reports and files. In the system, forward chaining reasoning is used to predict relay behavior while backward chaining reasoning is used to diagnose the reasons for inconsistency between expected and actual relay behavior. An example is given to demonstrate the capability of the prototype system.
This paper was accepted by the 18th International Conference on Electricity Distribution – CIRED, Turin, Italy, June 2005. The work was supported by PSerc Project T-17 "Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring". Uploaded May 14, 2005.		Mladen Kezunovic, Xu Luo5/15/2005383.8kPDF
05-28Fault Analysis Based on Integration of Digital Relay and DFR Data
This paper discusses integration of two existing automated analysis applications, DFR Data Analysis and Digital Relay Data Analysis, to achieve comprehensive fault analysis. As inputs to the integrated application, digital relay files and reports are introduced. The proposed strategy and implementation of integration are outlined. An example is used to demonstrate features of the integrated application developed so far.
This paper was accepted by IEEE PES General Meeting, San Francisco, CA, June 2005. The work was supported by PSerc Project T-17 "Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring". Uploaded May 14, 2005.		Xu Luo and Mladen Kezunovic5/15/2005704.7kPDF
05-29Interactive Protection System Simulation Using ATP MODELS and C++
This paper presents a new approach for interactive protection system simulation. In this approach, the power system network is modeled by the ATP program while the “compiled foreign model” mechanism of MODELS language is employed to model the digital protective relay in C++ language. This allows “object-oriented” relay modeling as well as building a “seamless” interface between the power system network model and the relay model. An example is used to demonstrate the interactive protection system simulation developed using the new approach. This paper was accepted by IEEE PES T&D Conference, New Orleans, October 2005. The work was supported by PSerc Project T-17 “Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring”. Uploaded May 14, 2005.		Xu Luo and Mladen Kezunovic5/15/2005307.1kPDF
05-30Static Security Analysis based on Vulnerability Index (VI) and Network Contribution Factor (NCF) Method
This paper introduces a new approach of power system static security analysis based on the Vulnerability Index (VI) and Network Contribution Factor (NCF) method. Vulnerability Index method provides quantitative vulnerability information about generation, transmission, load condition, and the whole system. NCF method gives fast approximate power flow results due to parameter change (contingency) based on the base load flow condition and network information. The contingency list can be chosen based on NCF method and VI evaluation. Comparison with the full AC power flow method shows that this approach is promising for fast and accurate static security analysis.
The paper has been accept by 2005 IEEE/PES T&D Asia Pacific. Uploaded May 15, 2005		Hongbiao Song and Mladen Kezunovic5/16/2005540.1kPDF
05-31A Novel Digital Relay Model Based on SIMULINK and Its Validation Based on Expert System
This paper presents the development of a novel digital relay model and its validation by a digital relay data analysis application. The model is developed as a SIMULINK S-function block. MATLAB file I/O functions are employed to generate an oscillography file and an event report. The expert system based digital relay data analysis application validates the relay model and generates diagnosis information for refining the model. An example is used to demonstrate the procedure of simulation, validation, and refining.
This paper was accepted by IEEE PES T&D Asia Pacific Conference, Da Lian, China, August 2005. The work was supported by PSerc Project T-17 "Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring". Uploaded May 16, 2005.		Xu Luo and Mladen Kezunovic5/16/2005193.4kPDF
05-32Implementing an Advanced Simulation Tool for Comprehensive Fault Analysis
Many large scale system blackouts involve relay misoperations. Traditional relay algorithms and settings need to be evaluated under a variety of fault and no-fault system-wide scenarios to better understand the causes for misoperations. New fault diagnosis algorithms also need to be developed to assure improved relaying performance and then evaluated under various scenarios. This paper introduces advanced fault analysis simulation software based on the interactive MATLAB and ATP simulation. The software consists of two major parts, power system simulation and relay algorithm evaluation. The former part can automatically generate thousands of system-wide events at one time and extract the transients for fault studies. The latter part includes the traditional distance relay model and two new advanced fault diagnosis algorithms. The structure of the software enables easy simulation setup for different power system models.
Paper for PSerc project (S-19). Appears in Proceeding of IEEE PES T&D Asia Pacific Conference, Da Lian, China, August 2005. Uploaded May 16, 2005.		Nan Zhang and Mladen Kezunovic5/18/2005233.2kPDF
05-33Criticality in a Cascading Failure Blackout Model
We verify and examine criticality in a 1000 bus network with an AC blackout model that represents many of the interactions that occur in cascading failure. At the critical loading there is a sharp rise in the mean blackout size and a power law probability distribution of blackout size that indicates a significant risk of large blackouts.
To appear at PSCC 2005 Liege Belgium. Uploaded May 18, 2005.		Dusko Nedic, Ian Dobson, Daniel Kirschen, Ben Carreras, and Vickie Lynch5/18/2005433.8kPDF
05-34Fault Current Calculation by The Least Squares Method
This paper contains the analysis of the increase of fault current due to the installation of DGs or merchant plants. An index called the Average Change of Fault Current, ACF, is proposed. The ACF can be applied to indicate the contribution of the increase of fault current and to allocate the responsibility of system upgrades among the owners of DGs. The least squares method for calculating the ACF is discussed. The confidence interval of the coefficients and mean response of ACF is discussed.
2004 North American Power Symposium, Moscow ID, August 2004, pp. 400 - 406. Uploaded May 23, 2005.		Natthaphob Nimpitiwan and Gerald T. Heydt5/24/2005454.5kPDF
05-35Fault Current Issues for Market Driven Power Systems with Distributed Generation
This paper presents the consequences and operating limitations of installing distributed generation (DG) to electric power systems. The proliferation of new generators creates new operating conditions, some not seen before, that are limited by fault interruption capability. Increased system fault currents resulting from DG installation and the effects of increased fault currents are discussed. A technique used to evaluate fault current in the system after installing DGs is analyzed, and an example is given. The responsibility for the system change and safety degradation is discussed.
Accepted for IEEE PES General Meeting, San Francisco, 2005. Uploaded May 23, 2005.		Natthaphob Nimpitiwan and Gerald T. Heydt5/24/2005568.4kPDF
05-38Differences in Capacity Requirements, Line Flows and System Operability under Alternative Deregulated Market Structures: Simulations Derived from Experimental Trials
How line flows, capacity requirements and system design might be altered under deregulated market structures is explored through simulations of experimentally-obtained loads and generator dispatches under alternative market structures, including a regulated base-case dispatch. Eight generators were located on the Power Web 30 bus simulated transmission network, and the 19 buyers were randomly allocated over thirty different trials to busses on the network. Line flows were estimated using a DC optimal power flow routine. Unambiguously, the sum of maximum flows over all lines is lower (by from one to ten percent) under a real-time pricing (RTP) regime, as compared to a simulation of the former regulated regime with fixed price (FP). Furthermore, a demand response program (DRP) is shown to perform nearly as well, resulting in lower maximum line flows in all but one of the allocations. RTP also restores line flow predictability close to operation under regulation.
Paper Presented at Power Engineering Systems 2005 Conference, San Francisco, CA June 12-16, 2005. Uploaded June 6, 2005.		Nodir Adilov, Thomas Light, Richard Schuler, William Schulze, David Toomey and Ray Zimmerman6/17/2005184.9kPDF
05-39Shooting Methods for Locating Grazing Phenomena in Hybrid Systems
Hybrid systems are typified by strong coupling between continuous dynamics and discrete events. For such piecewise smooth systems, event triggering generally has a significant influence over subsequent system behaviour. Therefore it is important to identify situations where a small change in parameter values alters the event triggering pattern. The bounding case, which separates regions of (generally) quite different dynamic behaviour, is referred to as grazing. At a grazing point, the system trajectory makes tangential contact with an event triggering hypersurface. The paper formulates conditions governing grazing points. Both transient and periodic behaviour are considered. The resulting boundary value problems are solved using shooting methods that are applicable for general nonlinear hybrid (piecewise smooth) dynamical systems. The grazing point formulation underlies the development of a continuation process for exploring parametric dependence. It also provides the basis for an optimization technique that finds the smallest parameter change necessary to induce grazing. Examples are drawn from power electronics, power systems and robotics, all of which involve intrinsic interactions between continuous dynamics and discrete events.
To appear International Journal of Bifurcation and Chaos. Uploaded July 27, 2005.		Vaibhav Donde and Ian A. Hiskens8/23/2005587.7kPDF
05-40Convexity of the Set of Feasible Injections and Revenue Adequacy in FTR Markets
The feasible set of power injections for the constrained power flow equations is non-convex when practical transmission capacity and bus voltage limits are imposed. The projection onto the space of active power injections may be “close” to convex, but this is not sufficient to guarantee revenue adequacy for the settlement of Financial Transmission Rights.
To appear IEEE Transactions on Power Systems. Uploaded: July 27, 2005. Revised: March 9, 2006.		Bernard C. Lesieutre and Ian A. Hiskens3/16/2006474.5kPDF
05-41Limit-Induced Stable Limit Cycles in Power Systems
Heavily loaded power systems are susceptible to Hopf bifurcations, and consequent oscillatory instability. The onset of instability can be predicted by small disturbance (eigenvalue) analysis, but the ensuring behaviour may depend strongly on nonlinearities within the system. In particular, physical limits place bounds on the divergent behaviour of states. This paper explores the situation where generator field-voltage limits capture behaviour, giving rise to a stable (though non-smooth) limit cycle. It is shown that shooting methods can be adapted to solve for such non-smooth limit-induced limit cycles. By continuing branches of limit-induced and smooth limit cycles, the paper established the co-existence of equilibria, smooth and non-smooth limit cycles. Furthermore, it is shown that when branches of limit-induced and smooth limit cycles merge, the limit cycles are annihilated at a grazing bifurcation.
P.B. Reddy and I.A. Hiskens, "Limit-induced stable limit cycles in power systems", Proceedings of the St. Petersburg PowerTech, Paper No. 603, St. Petersburg, Russia, June 2005. Uploaded July 27, 2005.		P.B. Reddy and I.A. Hiskens8/23/2005622.1kPDF
05-42Power System Modeling for Inverse Problems
Large disturbances in power systems often initiate complex interactions between continuous dynamics and discrete events. The paper develops a hybrid automaton that describes such behavior. Hybrid systems can be modeled in a systematic way by a set of differential-algebraic equations, modified to incorporate impulse (state reset) action and constraint switching. This differential-algebraic impulsive-switched (DAIS) model is a realization of the hybrid automaton. The paper presents a practical object-oriented approach to implementing the DAIS model. Each component of a system is modeled autonomously. Connections between components are established by simple algebraic equations. The systematic nature of the DAIS model enables efficient computation of trajectory sensitivities, which in turn facilitate algorithms for solving inverse problems. The paper outlines a number of inverse problems, including parameter uncertainty, parameter estimation, grazing bifurcations, boundary value problems, and dynamic embedded optimization.
Appears in IEEE Transactions on Circuits and Systems-I: Regular Papers, Vol. 51, No. 3, March 2004. Uploaded July 27, 2005.		Ian A. Hiskens8/23/2005321.0kPDF
05-43Dynamic Performance Assessment: Grazing and Related Phenomena
Performance specifications place restrictions on the dynamic response of many systems, including power systems. Quantitative assessment of performance requires knowledge of the bounding conditions under which specifications are only just satisfied. In many cases, this limiting behavior can be related to grazing phenomena, where the system trajectory makes tangential contact with a performance constraint. Other limiting behavior can be related to time-driven event triggering. In all cases, pivotal limiting conditions can be formulated as boundary value problems. Numerical shooting methods provide efficient solution of such problems. Dynamic performance assessment is illustrated in the paper using examples drawn from protection operation, transient voltage overshoot, and induction motor stalling.
IEEE Transactions on Power Systems. Uploaded July 27, 2005. Revised: March 9, 2006.		Vaibhav Donde and Ian Hiskens3/16/2006330.1kPDF
05-44Non-Uniqueness in Reverse Time of Hybrid System Trajectories
Under standard Lipschitz conditions, trajectories of systems described by ordinary differential equations are well defined in both forward and reverse time. (The flow map is invertible.) However for hybrid systems, uniqueness of trajectories in forward time does not guarantee flow-map invertibility, allowing non-uniqueness in reverse time. The paper establishes a necessary and sufficient condition that governs invertibility through events. It is shown that this condition is equivalent to requiring reverse-time trajectories to transversally encounter event triggering hypersurfaces. This analysis motivates a homotopy algorithm that traces a one-manifold of initial conditions that give rise to trajectories which all reach a common point at the same time.
I.A. Hiskens, ''Non-uniqueness in reverse time of hybrid system trajectories'', in Hybrid Systems: Computation and Control, M. Morari and L. Thiele (Editors), Springer Lecture Notes in Computer Science, Berlin, 2005. Uploaded July 27, 2005.		Ian A. Hiskens8/23/2005646.1kPDF
05-45Observed Hybrid Oscillations in an Electrical Distribution System
Slow oscillations, with a period of around 15 minutes, were observed in an 11kV electrical distribution system. Investigations determined that the oscillations were a result of interactions between tap-changing transformers and switched capacitors. Analysis required a hybrid systems framework, due to the non-smooth (switched) nature of these interactions. It was found that the oscillations could be suppressed by adjusting the lower limit of the capacitor deadband. A grazing bifurcation separated oscillatory from steady-state behaviour.
V. Donde and I.A. Hiskens, "Observed hybrid oscillations in an electrical distribution system", Proceedings of the IEEE International Symposium on Circuits and Systems, Kobe, Japan, May 2005, pp. 4179-4182.		Vaibhav Donde and Ian A. Hiskens8/23/2005398.2kPDF
05-46Interface between Engineering and Market Operations in Restructured Electricity Systems
We examine the impact of wholesale markets on operations of the bulk power system and elaborate some basic implications of engineering practices for designs of wholesale markets. This analysis is intended to provide a basis for enhancements to existing principles of engineering management. Wholesale markets bring economic and financial aspects that alter the context in which system operations are conducted, and introduce incentive and benefit-cost considerations that might alter operating procedures that previously were based on reliability considerations. The principles addressed are those relevant to the interface between engineering aspects of system operations, and economic aspects of market operations. We outline ways that engineering practices developed in the era of vertically integrated utilities might be adapted to the wholesale markets introduced since restructuring began in 1998 in the U.S.		Hung-po Chao, Shmuel Oren, Alex Papalexopoulos, Dejan Sobajic, and Robert Wilson11/16/2005487.9kPDF
05-47An Estimator of Propagation of Cascading Failure
We suggest a statistical estimator to measure the extent to which failures propagate in cascading failures such as large blackouts. The estimator is tested on a saturating branching process model of cascading failure and on failure data generated by the OPA simulation of cascading blackouts. The estimator is a standard estimator for the branching process parameter modified so as to avoid saturation effects. We discuss the statistical effectiveness of the estimator and show how estimating the failure propagation and the initial failures leads to estimates of the distribution of the numbers of cascading failures. The estimator is derived from a simple and high-level branching process model of cascading failure. We discuss how branching process approximations and in particular the propagation parameter may arise in several different models, including models of interacting infrastructures.
This paper will appear at HICSS January 2006. Uploaded Sep. 19, 2005.		Ian Dobson, Kevin Wierzbicki, Ben Carreras, Vickie Lynch, David Newman9/19/2005553.9kPDF
05-48Issues Associated with the Development of a Wide-Area Analysis and Visualization Environment
This paper provides a discussion of issues associated with the development of an environment for wide-area power system analysis and visualization. In particular, the paper considers issues associated with the exchange of information between regional transmission operators, the use of a unified state estimation and contingency analysis solution, and the visualization of the results.
John P. Stovall, Brendan J. Kirby, Thomas J. Overbye, James S. Thorp, and Arun G. Phadke10/6/20051.9MPDF
05-49Condition Data Aggregation with Application to Failure Rate Calculation of Power Transformers
Cost-effective equipment maintenance for electric power transmission systems requires ongoing integration of information from multiple, highly distributed, and heterogeneous data sources storing various information about equipment. This paper describes a federated, query-centric data integration and knowledge acquisition framework for condition monitoring and failure rate prediction of power transformers. Specif- ically, the system uses substation equipment condition data collected from distributed data resources, some of which may be local to the substation, to develop Hidden Markov Models (HMMs) which transform the condition data into failure probabilities. These probabilities pro- vide the most current knowledge of equipment deterioration, which can be used in system-level simulation and decision tools. The system is illustrated using dis- solved gas-in-oil eld data for assessing the deterioration level of power transformer insulating oil.
Copyright 2005 IEEE. To Be Published in the Proceedings of the Hawai'i International Conference On System Sciences, January 4-8, 2005, Kauai, Hawaii. Uploaded: Sep. 19, 2005.		Jyotishman Pathak, Yong Jiang, Vasant Honavar, and James McCalley9/20/2005446.3kPDF
05-50Two-Sided Electricity Markets: Self-Healing Systems
High voltage electricity systems may become more reliable under market-based dispatch than they were under cost-based, regulated assignments if customers are faced with real-time prices.
Paper Presented at 2005 CREATE Workshop, August 19-20, 2005. Uploaded: Nov. 30, 2006.		Richard E. Schuler11/30/2006210.3kPDF
05-51Monitoring of Power System Topology in Real-Time
Power system topology is defined by the connectivity among power system components such as generators, power transformers, transmission lines, loads, etc. The knowledge about topology is important for correct execution of many monitoring, control and protection actions. This paper introduces an approach that assures accurate determination of the topology in real-time. To be able to justify why this approach is important, the paper gives a background of the topology determination problem and discusses the impact on various application functions. An implementation of the proposed approach consisting of hardware and software modules is outlined. Examples of the functional improvements due to the increased accuracy of topology determination at both the substation and system-wide level are presented at the end.
Copyright 2005 IEEE. To appear in the proceedings of the Hawai'i International Conference on System Sciences, HICSS 39, Kauai, Hawaii, Symposium on Electric Power Systems Reliability,January 4-5, 2006. Uploaded: Sep. 20, 2005.		Mladen Kezunovic9/20/2005752.9kPDF
05-52Strategies to Address the Problem of Exiting Expertise in the Electric Power Industry
Retirements, restructuring, and technology changes are producing an accelerating exodus of expertise from the electric power industry. In this paper we review the major approaches to address that challenge: managing available resources, outsourcing, automating, recording, and educating. The approaches may all be used in a comprehensive strategy to overcome exiting expertise. Each approach has different implications for the resources needed to be successful. The responses to date have not been sufficiently comprehensive and of adequate scale to address the looming workforce losses. Our thesis is that the needed leadership by executives, policymakers, and academia to comprehensively address the expertise exodus challenge will be enhanced by a better understanding of the diverse approaches and of where effective intervention with sufficient resources is needed.
Copyright 2005 IEEE. To be Published in the Proceedings of the Hawai'i International Conference on System Sciences, Symposium on Electric Power Systems Reliability, January 4-8, 2005, Kauai, Hawaii. Uploaded: Sep. 20, 2005.		Dennis Ray and Bill Snyder9/20/2005580.1kPDF
05-53Managing Relationships Between Electric Power Industry Restructuring and Grid Reliability
This paper discusses the relationship between restructuring and reliability, identified organizational complexities arising from restructuring, argues that there is a continuing need for R&D even though resources have been declining, reminds us about the looming manpower crisis, and concludes with four recommendations for maintaining reliability while restructuring.
Prepared for two Workshops entitled "Competition and Reliability in North American Energy Markets" sponsored by the U.S.-Canada Power System Outage Task Force, September 2005. Uploaded: Sep. 20, 2005.		Robert J. Thomas9/20/20051.1MPDF
05-54Electricity Markets: How Many, Where and When?
Most markets compromise the economist’s ideal of matching the marginal benefits to consumers with the marginal cost of supply for incremental purchases because individual buyers and sellers are aggregated over space, time and/or other product attributes like quality or reliability. These aggregations into discrete market segments are designed to facilitate transactions by reducing search and distribution costs, and they may enhance the competitiveness of each market segment by encompassing a larger number of buyers and sellers, but at some loss of precise efficiency matches. Furthermore, as individual market segments grow in size, the price differences across their boundaries may also increase which can raise the transactions costs associated with increased arbitrage. These are important considerations for electricity markets since significant physical, operational and capacity barriers separate and define these markets over space and time. Thus principles for the optimal structure of these markets are developed, and in particular, it is shown that forward markets with lead times longer than the gestation period required to construct new generation capacity are essential to insure efficient subsequent spot markets. By comparison, if these forward markets occur only after new construction is begun, as with existing installed capacity markets, spot market prices may be higher. Similarly, the extent of separation and spacing of markets across regions and control areas, particularly in the face of transport congestion or operational boundaries, is important for enhanced efficiency.
Presented at HICSS 39, Kauai, Hawaii, Symposium on Electric Power Systems Reliability, Control and Markets, January 4-5, 2006. Uploaded Sep. 19, 2005.		Nodir Adilov and Richard E. Schuler9/20/2005186.5kPDF
05-55Market Redesign: Incorporating the Lessons Learned for Enhancing Market Design
The Market Mechanisms Project focused on (1) the design of electricity auctions for energy and ancillary services; (2) the development of financial engineering based models for generation asset valuation; (3) the investigation of usable definitions of transmission rights; and (4) the study of methods for congestion management and of the formulation of price mechanisms and incentives for demand response. The principal focus was on issues that have been identified as open questions and on areas targeted as particularly being in critical need of improvement.

This is the final project report from "Market Redesign: Incorporating the Lessons Learned from Actual Experiences for Enhancing Market Design (M-4)." Draft submitted: Aug. 26, 2005. Final report uploaded: Sep. 27, 2005. Member Viewing Only.

Shmuel Oren, Project Leader9/29/2005LinkURL
05-56Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs: Part I
This report is Part I of a study aimed at demonstrating how the reliability of substation operation may be enhanced using data collected by Intelligent Electronic Devices (IEDs). To achieve major operational reliability benefits, data collected by IEDs can be processed in real time to extract information to improve reliability. This report (Part I) discusses the applications that may be executed locally, while Part II talks about applications that are related to the overall power system operation and that may be located at the Energy Management System (EMS) level.

Part I of the final project "Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring (T-17)." Draft received: Aug. 26, 2005. Final report uploaded: Oct. 4, 2005.

Mladen Kezunovic, project leader10/7/2005LinkURL
05-57Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDS (Part II): Detecting Circuit Breaker Status Errors in Substations
Recently a new method, based on a reduced system model and Lagrange multipliers, was proposed for topology error analysis. In this method, the size of a detailed substation model is reduced by applying Kirchhoff’s law and by implicitly considering topological constraints. This model reduction is achieved without losing any capability to detect and identify topology errors. The method has an important advantage over existing topological analysis techniques in that the user does not have to specify the suspect substation ahead of time because all substations can be modeled by using a small number of extra state variables. The main two purported advantages of the implemented method are its ability to detect status errors associated with substation breakers without significantly increasing the size of the network model, and to differentiate between analog measurement errors and breaker status errors. Both advantages were validated using simulated cases. As a result, the method is recommended as a new feature for state estimation software.

Part II of the final project "Enhanced Reliability of Power System Operation Using Advanced Algorithms and IEDs for On-Line Monitoring (T-17)." Draft received: Sep. 9, 2005. Final report uploaded: Oct. 4, 2005.

Ali Abur10/7/2005LinkURL
05-58Optimal Placement of Phasor Measurement Units for State Estimation
This report describes a study undertaken to determine the optimal locations of phasor measurement units (PMUs) for a given power system. Power systems are rapidly becoming populated by PMUs. PMUs have multiple uses at substations. They provide valuable phasor information for protection and control of power systems during abnormal operation. Under normal operations, they also help in monitoring the system state. This project focuses on the use of PMU measurements in state estimators. The principle objective was to investigate methods of determining optimal locations for PMUs so that the system state of an entire power system can be observable. Two new procedures were used to solve the problem of optimally locating PMUs. We found that the entire system can be made observable by strategically placing PMUs at one-third of the system buses for a given system. Fewer PMUs may be needed if there are zero injection buses in the system. This is the final project report from "Optimal Placement of Phasor Measurement Units for State Estimation (S-23g)." The project was funded with Additional Membership Funds from TVA. Draft submitted: July 31, 2005. Final report uploaded: Oct. 5, 2005.		Ali Abur, project leader10/7/2005LinkURL
05-59Detection, Prevention and Mitigation of Cascading Events: Part I
This research develops and describes new technologies for monitoring and control at the system and local levels. To achieve more reliable operation, power system operators could benefit from new tools that provide an interactive scheme to detect and prevent possible cascading events. For system monitoring and control, the technologies include routine and event-based security analysis, along with security control schemes. The local monitoring and control consists of an advanced real time fault analysis tool and a relay operation monitoring tool. The system monitoring and control tool can be installed at control centers. The local monitoring and control tool can be installed at substations. The test beds used to demonstrate the scheme for detection and prevention of cascading events are the IEEE 14-bus and 39-bus systems, the WECC 9-bus system, and the CenterPoint Energy SKY-STP system. This is Part I of the final report for the PSERC project "Detection, Prevention and Mitigation of Cascading Events" (S-19). Draft received: Aug. 22, 2005. Final report uploaded: Oct. 7, 2005.		Mladen Kezunovic, Hongbiao Song and Nan Zhang10/7/2005LinkURL
05-62Preventing Future Blackouts by Means of Enhanced Electric Power Systems Control: From Complexity to Order
This paper concerns the critical role enhanced control will play in the operating of future electric power systems reliably and effi- ciently. The nonstandard control problems are due to a large variety of controllers, presently acting in a multirate mode at various levels of the system. Today’s monitoring and control logic is largely effective during normal conditions. This paper concerns its possible enhancements which might enable the system to operate reliably over broader ranges of loading and equipment status. In particular, it is suggested that major benefits could come from providing computer tools to assist human operators with their decision making when the system is under stress. A multilayered approach is introduced to support: 1) on-line adjustment of available resources; 2) monitoring the interconnection based on qualitative indices (QIs) essential for deciding the severity of the operating mode; and 3) using the QIs to adjust structure of control as the system evolves from one mode to the next. An equivalenced model of the Northeast Power Coordinating Council (NPCC) interconnection is used to illustrate the potential of enhanced control in scenarios that resemble the blackout of August 2003. Also, the potential for efficient use of the resources during normal conditions is illustrated using this multilayered monitoring and control architecture.
Proceedings of the IEEE, vol. 93, no. 11, November 2005. Uploaded: Oct. 7, 2005.		Marija Ilíc, Eric Allen, Jeffrey J. Chapman, Charles A. King, Jeffrey H. Lang, and Eugene Litvinov10/7/20051011.5kPDF
05-66Optimal Market Grain Over Space and Time
Markets facilitate the exchange of precise quantities of goods and services at particular locations and times; yet for convenience and to reduce transactions costs, these markets customarily specify the terms (e.g. the price) uniformly over a substantial interval of space and time. If customers’ tastes and producers’ costs vary continuously over these dimensions, then assessing uniform prices within these market intervals leads to economic inefficiencies (marginal value unequal to marginal cost) for many participants, and it affords incentives for hedging at the boundaries of these market segments where prices differ. The determination of an optimal “grain” for market design, therefore, requires the balancing of four different categories of costs: (1) the inefficiency from not equating marginal benefit and marginal cost for every transaction, (2) the increasing transactions (decision) costs of having a larger number of market segments, (3) the increased hedging costs across the boundaries if there are fewer market segments and therefore greater price disparities, and (4) the increased opportunity for participants to exercise market power as fewer competitors are aligned with each segment of a more finely-grained market structure. One practical application for these concepts is in the emerging markets for electricity where the spatial grain, locational marginal pricing (LMP) based on congested points in the transportation system, provides incentives for the geographic investment in new generation facilities that could ultimately alter line flows, and therefore congestion -- the rationale for the original spatial structure.
Presented at the Rutgers Advanced Workshop in Regulation and Competition, 24th Annual Eastern Conference, Skytop, PA, May 18-20, 2005		Nodir Adilov and Richard E. Schuler11/16/200567.1kPDF
05-67Volumetric Hedging in Electricity Procurement
Load serving entities (LSE) providing electricity service at regulated prices in restructured electricity markets, face price and quantity risk. We address the hedging problem of such a risk averse LSE. Exploiting the correlation between consumption quantities and spot prices, we developed an optimal, zero-cost hedging function characterized by payoff as function of spot price. We then show how such a hedging strategy can be implemented through a portfolio of call and put options.
Proceedings of the PowerTech 2005 Conference, St. Petersburg, Russia, June 27-30, 2005. Uploaded: Nov. 28, 2005.		Yumi Oum, Shmuel Oren and Shijie Deng11/28/2005172.3kPDF
05-68Conflicting Investment Incentives in Electricity Transmission
A key issue is that transmission investments have important distributional impacts. This means, for instance, that while society as a whole may benefit from the elimination of congestion, some parties may be harmed. Likewise, the maximization of social welfare, the minimization of local market power, the maximization of consumer surplus, and the maximization of producer surplus can all result in divergent optimal expansions of the transmission network. Moreover, even when the optimizing objective is clearly determined, the optimal network expansion under that objective changes depending on the cost structure of generators. This interrelationship between generation and transmission investments must be incorporated when evaluating any transmission expansion. However, defining the optimal expansion of a network as a function of the strategic behavior of generators is a very complex task due to network externalities and the complementarities and substitutabilities of different generation and transmission expansion projects.
Panel presentation at the IEEE PES Annual Meeting, San Francisco, CA June 12-16, 2005. Uploaded: Nov. 28, 2005.		Enzo Sauma and Shmuel S. Oren11/28/200536.7kPDF
05-69Automated Monitoring Functions for Improved Power System Operation and Control
This paper describes how new functions for automated analysis of data collected in substations of an electric power system can be developed. The new functions are first defined and architecture of the integrated substation solution is proposed. Database and user interfacing needs are also presented. Once fully implemented, this solution will serve both local and remote operators allowing further benefits to be drawn from the concept of substation data integration and information exchange.		Mladen Kezunovic and G. Latisko3/9/2006218.5kPDF
05-70Non-Collocated Power Measurements in a Power System State Estimator
This paper addresses a problem in state estimators for power systems. The issue of non-collocated measurements is studied. The measurement of P+jQ in a line or at a bus is usually accomplished by measuring voltage and current at an appropriate point. A transducer converts the voltage and current measurement to active and reactive power which are transmitted to the state estimator. If the voltage and current measurements are not at the same point in the circuit, that is the measurements are non-collocated, error is introduced. The paper reports a way to correct for non-collocation of measurements.
North American Power Symposium, Ames IA, October, 2005. Uploaded: June 5, 2006.		B. Mann, G. Heydt and G. Strickler6/8/2006237.8kPDF
05-71A Method for Classifying Offer Strategies Observed in an Electricity Market
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.
Decision Support Sytems, Vol. 40, Nos. 3&4, October 2005. Uploaded: June 27, 2006.		HyungSeon Oh, Robert J. Thomas, Bernard C. Lesieutre, Timohty D. Mount6/27/2006571.3kPDF
05-72Reliability, Electric Power, and Public vs. Private Goods: A New Look at the Role of Markets
The economic theory that has been used to support restructuring of the electric power industry has ignored several important technological constraints and public goods that affect the way in which power is delivered. Some of these public goods include voltage, frequency, and reliability of lines. Similarly, engineers, by using security-constrained optimization to incorporate the demand for reliability, have failed to properly define the economic problem. This research attempts to remedy this deficiency through a collaborative effort between economists and engineers to examine the theoretical and empirical properties of a networked power system that provides economically optimal reliability and draw conclusions regarding efficient market design.
Proceedings of the 38th Hawaii International Conference on System Sciences, Jan. 3-6 2005. Uploaded: Nov. 30, 2006.		David Toomey, William Schulze, Richard Schuler, Robert Thomas, and James Thorp12/1/2006216.1kPDF
05-73Proactive Planning and Valuation of Transmission Investments in Restructured Electricity Markets
Traditional methods of evaluating transmission expansions focus on the social impact of the investments based on the current generation stock which may include firm generation expansion plans. In this paper, we evaluate the social welfare implications of transmission investments based on equilibrium models characterizing the competitive interaction among generation firms whose decisions in generation capacity investments and production are affected by both the transmission investments and the congestion management protocols of the transmission system operator. Our analysis shows that both the magnitude of the welfare gains associated with transmission investments and the location of the best transmission expansions may change when the generation expansion response is taken into consideration. We illustrate our results using a 30-bus network example.
INFORMS Meeting, Invited Talk, San Fransisco, CA, Nov. 13-16, 2005. Uploaded: Nov. 30, 2005.		Enzo E. Sauma and Shmuel S. Oren11/30/2006340.4kPDF
05-74Testing the Effect of Inter-Regional Transfers of Real Energy on the Performance of Electricity Markets
Since deregulation of the electric utility industry began in the USA, there has been a substantial increase in the quantity of power transferred over long distances. Both thermal and voltage constraints on transmission have been experienced in regions that previously were rarely congested. One solution to this type of problem is to expand the capacity of transmission networks, but it is likely that market forces will still cause congestion (in new locations) on an expanded network. The objectives of this paper are 1) to test how power transfers through a network affect congestion and market performance, and 2) to explain the complications and limitations of treating an AC network like a pipeline as a way to compensate transmission owners.
Presented at the 18th Annual Western Conference, Center for Research on Regulated Industries, Rutgers University, June, 2005. Uploaded: Feb. 8, 2007.		T.D. Mount and R.J. Thomas2/8/20071.3MPDF
05-75Induction Motor Load Dynamics: Impact on Voltage Recovery Phenomena
This paper addresses the impact of load dynamics, and in particular induction motor loads, on voltage recovery after disturbances. The paper proposes a methodology that is based on load flow techniques with advanced modeling capabilities, augmented by a simplified induction motor dynamic model. The objective is to realistically capture the dynamic characteristics of voltage recovery phenomena, avoiding, however, the full scale transient simulation. The approach uses the quadratized power flow model with explicit induction motor representation. The paper describes the modeling approach and the overall methodology for evaluating the load dynamics on voltage recovery. Preliminary results of the application of the method on a simple power system with load dynamics are also included in the paper.
Proceedings of the IEEE T&D Conference, New Orleans, LA, Oct. 2005. Uploaded: Feb. 9, 2007.		George K. Stefopoulos and A. P. Meliopoulos2/9/2007424.8kPDF

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