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2001 Publications


Computer Simulation of Cascading Disturbances in Electric Power Systems
The restructuring of electricity industry has renewed concerns about wide-area disturbances due to their increasing economic and social costs. Hidden failures in power protection systems play significant roles in propagating these disturbances. Through computer simulations, we analyze the impact of consecutive relaying malfunctions and define the protection system vulnerability and reliability to numerically characterize this impact. A heuristic random search algorithm is developed for fast rare- event simulation of cascading outages. An optimal system upgrading strategy is proposed for the economical enhancement of protection system reliability under limited budget. We examine these techniques in a case study of New York Power Pool (NYPP) 3000-bus system.
Final report for PSERC project "Impact of Protection Systems on Transmission System Reliability: Computer Simulation of Cascading Disturbances in Electric Power Systems" (S-4). Uploaded: June 25, 2001.  
Hongye Wang, and James S. Thorp 06/25/01 279.56 KB PDF 01-01
CPFLOW for Power Tracer and Voltage Monitoring
This report describes CPFLOW (Continuation Power Flow), a comprehensive software tool for tracing power system steady-state behaviors due to large or small variations in loads, generation, transactions, interchanges, and imports and exports. CPFLOW is designed for the analysis of large-scale power systems and can trace a solution curve through the ‘nose’ point without the numerical difficulties of repeated power flow solvers. CPFLOW can be used in a variety of applications for power system analyses (such as monitoring voltage behaviors, calculating transfer capabilities, etc.) and for analysis of transactions and transmission services.
Final report for PSERC project "Voltage Collapse Margin Monitor: CPFLOW for Power Tracer and Voltage Monitoring" (S-2). Uploaded: April 3, 2003.  
Hsiao-Dong Chiang and Hua Li 04/03/03 273.10 KB PDF 01-02
Is Strong Modal Resonance a Precursor to Power System Oscillations?
We suggest a new mechanism for interarea electric power system oscillations in which two oscillatory modes interact near a strong resonance to cause one of the modes to subsequently become unstable. The possibility of this mechanism for oscillations is shown by theory and computational examples. Theory suggests that passing near strong resonance can be expected in general power system models. The mechanism for oscillations is illustrated in 3 and 9 bus examples with detailed generator models. This paper appears in IEEE Transactions on Circuits and Systems, Part I, March 2001 and was supported by the PSERC oscillations project and NSF.
IEEE Transactions on Circuits and Systems - I. Fundamental Theory and Applications, vol. 48, no. 3, March 2001. Uploaded: April 26, 2001.  
Ian Dobson, Jianfeng Zhang, Scott Greene, Henrik Engdahl, Peter W. Sauer 04/26/01 174.85 KB PDF 01-04
Automated Operating Procedures for Transfer Limits
A Modern Energy Management System (EMS) provides sophisticated online security analysis applications to assist operators in ensuring that the power system can survive credible contingencies. Still in current practice, system operators generally refer to written operating procedures to establish system constraints, particularly in regards to transfer limits across major interties. The limits are based on numerous power system studies that represent the stressed system and satisfy specific performance criteria following select contingencies. The relations between these critical paths and operating conditions are tabulated and often plotted as nomograms. With such a simplified view of system conditions, the operator is unable to have a complete understanding of operational limits. Thus, transfer ratings are typically conservative, as studies are based on highly stressed system conditions, and incomplete, as studies cannot analyze all combinations of equipment out-of-service. This study investigates some approaches to improving such operator procedures. Results demonstrate the ability of neural net estimators, trained off-line, to estimate margins in real-time.
Final report for PSERC project "Automated Operating Procedures for Transfer Limits" (S-5). Uploaded: June 25, 2001.  
Liqiang Chen, Kevin Tomsovic, and Anjan Bose 06/25/01 636.23 KB PDF 01-05
Adaptive Power Flow Method for Distribution Systems with Dispersed Generation
This paper presents an adaptive distributed power flow solution method based on the compensation-based approach. The numerical properties of the compensation-based power flow method are compared and analyzed under different situations, such as load unbalance, sudden increase of one-phase loads, degree of meshed loops, number of generator nodes and so on. Based on these analyses, an adaptive compensation-based power flow method is proposed that is fast and reliable while maintaining necessary accuracy. It is illustrated that this adaptive method is especially appropriate for simulation of slow dynamics in the distribution system.
Submitted to IEEE for publication. Uploaded: October 25, 2001.  
Yaming Zhu and Kevin Tomsovic 10/25/01 223.17 KB PDF 01-06
Communication Models for Third Party Load Frequency Control
With deregulation of the power generation sector, the necessity for an enhanced and open communication infrastructure to support an increasing variety of ancillary services is apparent. A duplex and distributed communication system seems to be the most suitable solution to meet and ensure good quality of these services. Parameters needed and additional limits introduced by this new communication topology must be investigated and defined. This paper focuses on the communication network requirements for a third party load frequency control service. Data communication models are proposed based on queuing theory. Simulation is performed to model the effects of certain types of signal delays on this ancillary service.
Submitted to IEEE for publication. Uploaded: October 25, 2001.  
Sudipto Bhowmik, Kevin Tomsovic, and Anjan Bose 10/25/01 194.67 KB PDF 01-07
Dynamic Voltage Stability Reserve Studies For Deregulated Environment
This paper first analyzes why voltage instability occurs in mature yet competitive power systems, and then investigate diverse voltage stability issues in deregulated power markets using a commercial transient simulation program EUROSTAG. Dynamic behaviors of major power system components, i.e., speed governor, excitation element, inductive motor, ULTC and mechanically switched shunt capacitor et al, are thoroughly examined by a small yet typical equivalent system. The presented simulation results help better understand the mechanism of the voltage collapse phenomena, and highlight the importance of dynamic reactive reserves, like generators, in dynamic voltage stability enhancement.
Uploaded: April 26, 2001.  
Garng Huang, H. Zhang 04/26/01 203.13 KB PDF 01-08
Measurement Based Voltage Stability Monitoring of Power System
Many papers discuss the voltage stability assessment of power system using power flow analysis methods. In this paper, a method for online monitoring of a power system based on measurements is proposed, which is aimed at detection of the voltage instability. Thereby an indicator is derived from the fundamental Kirchoff-Laws. Since in the transient process, at any time point, the electric power of the system is in balance, and the Kirchoff-Law is obeyed, this indicator will still work during the transient process. From the indicator, it is allowed to predict the voltage instability or the proximity of a collapse. The advantage of the method lies in the simple numerical calculation and strong adaptation in steady state and transient process. Through the indicator of voltage stability, it is easy to find the most vulnerable area in a system, to find the impacts of other loads, areas and power transactions.
Uploaded: April 26, 2001.  
Garng Huang, Liang Zhao 04/26/01 56.16 KB PDF 01-09
TCSC as a Transient Voltage Stabilizing Controller
TCSC has been proposed to enhance the voltage stability by changing the reactive power distribution in the power system. Authors have discussed the effect of TCSC on steady state voltage stability and small-signal voltage stability. This paper discusses the TCSC’s enhancement on transient voltage stability. A TCSC model that is suitable for transient voltage stability analysis is proposed. This model is tested on a multi-machine system including all the key elements relevant to system voltage performance. The simulation shows that angle -stability-enhancement-like TCSC controllers offer little help for certain transient voltage stability crises. Based on this analysis, a new TCSC controller is proposed and proved to enhance the transient voltage stability.
Uploaded: April 26, 2001.  
Garng Huang, Tong Zhu 04/26/01 159.46 KB PDF 01-10
Transaction Based Power Flow Analysis For Transmission Utilization Allocation
This paper proposes a framework of transaction based power flow analysis (TBPF) for transmission utilization allocation. The TBPF utilizes distributed purchase-sale pairs to replace the role of a single slack bus on energy imbalance during power flow calculation iterations. To compare with conventional power flow analysis, accurate allocation of use-of-transmission is part of a TBPF solution. In particular, the TBPF is able to identify interaction components among transactions as well as the effect of reactive power on transmission losses and active power flows. Two allocation rules for cross terms are proposed to hedge firm or existing transactions against market risk. The standard WSCC 9 bus system is used to demonstrate the performance of the TBPF.
Uploaded: April 26, 2001.  
Garng Huang, H. Zhang 04/26/01 69.96 KB PDF 01-11
Rational Buyer Meets Rational Seller: Reserves Market Equilibria under Alternative Auction Designs
We examine efficiency properties and incentive compatibility of alternative auction formats that an electricity network system operator may use for the procurement of ancillary services required for real-time operations. We model the procurement auction as a hierarchical multiproduct auction, and study several designs such as a uniform price auction minimizing social cost, a uniform price auction minimizing the system operator's cost and a pay as bid auction. We take into account that rational bidders will respond to any market design so as to maximize their expected benefit from participating in that market. Under the assumptions of our model, we show that the uniform price auction minimizing social cost is the only one that guarantees productive efficiency. We also find that expected revenue (payment in our case) equivalence between pay as bid and uniform price auction does not extend to the hierarchical products case and the ranking of these auctions is ambiguous and depends on the data. For the procurement auction minimizing the system operator's cost, we show that misrepresentation of capability may result in capacity shortages if there are capacity constraints. For the case where only higher capability resources are constrained, this will result in random price spikes decreasing in frequency with the price cap (this is the amount paid to capacity in demand states with shortages). When lower type resources are capacity constrained as well, price spikes will be seen for both type of resources. Arti cial shortages result in reduced reliability in real-time operations.
Copyright 2001 Kluwer Academic Publishers. Printed in the Netherlands. Uploaded: April 27, 2001.  
Rajnish Kamat and Shmuel S. Oren 04/27/01 711.54 KB PDF 01-12
Exotic Options for Interruptible Electricity Supply Contracts
Abstract - This paper presents the design and pricing of financial contracts for the supply and procurement of interruptible electricity service. While the contract forms and pricing methodology have broader applications, the focus of this work is on electricity market applications, which motivate the contract structures and price process assumptions. In particular, we propose a new contract form that bundles simple forwards with exotic call options that have two exercise points with different strike prices. Such options allow hedging and valuation of supply curtailment risk, while explicitly accounting for the notification lead time before curtailment. The proposed instruments are priced under the traditional GBM price process assumption and under the more realistic assumption (for electricity markets) of a mean reverting price process with jumps. The latter results employ state of the art Fourier transforms techniques.
Revised version: April 3, 2001. Uploaded: April 27, 2001.  
Rajnish Kamat and Shmuel S. Oren 04/27/01 607.95 KB PDF 01-13
Prospects for Dynamic Transmission Circuit Ratings
In this paper, the basic concepts of dynamic thermal ratings of overhead transmission conductors are discussed. The sensitivity of these ratings with ambient conditions is evaluated. Innovative concepts in the measurement of overhead sag are given and correlated with dynamic rating of overhead transmission conductors. Dynamic transmission line thermal ratings take on increased importance in the deregulated electric power industry, since transmission capacity is sold as a deregulated commodity. Also, the electric utilities are under pressure to utilize all their transmission resources to the fullest.
Uploaded: May 1, 2001.  
Keith E. Holbert and Gerald T. Heydt 05/01/01 112.46 KB PDF 01-14
Storing Arb: Methods for Storage Valuation
We present methods for valuation of virtual and physical storage contracts. This paper presents a theoretical framework for gas storage valuation. In fact, the methods developed in this paper apply to essentially any commodity storage problem with a liquid forward market. Of particular note is pump storage in power markets (this includes air compression facilities and water pumping reservoirs) which can be optimized using our approach, although the injection/withdrawal costs will be substantially higher than in gas storage.
Uploaded: May 7, 2001.  
Hyungsok Ahn, Albina Danilova, and Glen Swindle 05/07/01 66.09 KB PDF 01-15
An Engineering Approach to Monitoring Market Power in Restructured Markets for Electricity
Abstract - The high average prices and high volatility of prices in many restructured markets for electricity have raised concerns about the abuse of market power by generators. At the same time, information about the true costs of generation, that was readily available under regulation, is no longer disclosed by generators. Hence, it is becoming impractical to use a comparison of actual prices with competitive prices as the basis for identifying the use of market power. In this paper, an engineering procedure is proposed for a given pattern of dispatch to measure the potential for market power for all generators in a network. This procedure is equivalent to a set of factor demand equations in a standard neoclassical model of production. An optimal dispatch, for given sets of offers to sell and constraints on capacity, can be replicated exactly by resolving the dispatch using the optimal nodal prices as offers with no constraints on capacity. Market power exists when the degree of substitutability for power generated at a particular site is low. Withholding capacity and/or raising offers to sell at such a site would be one of the possible ways to exploit market power. Sensitivity of the results for any given pattern of dispatch can give some indication of how effectively prices have been raised by a generator.
Under competitive conditions, submitting higher offers to sell at a site will result in a substantial reduction of the capacity dispatched, and the own-price elasticity of demand for generation at the site is very large (negative). As market power increases, the own-price elasticity gets smaller and approaches zero. These effects can be aggregated easily to deal with a specified group of generators, which could represent generators in a load pocket or ownership by a parent company. Use of these procedures is illustrated by evaluating the results of two experiments designed to test market power. These experiments were conducted with undergraduates and utility executives using POWERWEB, which simulates a full AC network with 30 buses, six of which are generators. The objective of the experiments was to determine whether two of the generators could discover that they were in a load pocket and raise their profits by exploiting market power.
Uploaded: June 25, 2001.  
Carlos E. Murillo-Sanchez, Simon M. Ede, Timothy D. Mount, Robert J. Thomas, and Ray D. Zimmerman 06/25/01 243.01 KB PDF 01-17
Testing the Performance of Uniform Price and Discriminative Auctions
The high prices that occurred in southern California since the Summer, 2000 led to a substantial amount of regulatory and political intervention. Price caps were lowered and the Federal Energy Regulatory Commission (FERC) proposed that a new type of “soft cap” auction should be adopted. This auction combines a standard uniform price auction with a discriminative auction for offers higher than a specified level ($150/MWh). Nevertheless, there is little available evidence to show that this new auction works well, or guarantees lower average prices. The objective of this paper is to provide some experimental evidence about the relative performance of different types of auctions for electricity markets. The experiments involved engineering and economic graduate students at Cornell University and the University of Illinois, and regulators in the New York State Department of Public Service. These individuals represent generators in a “smart” market, POWERWEB. This market replicates the physical constraints of meeting loads in an electrical grid. The first part of this paper describes how the high price volatility observed in many electricity markets can be replicated. The key features are:
    1) load is stochastic,
    2) incentives are provided to withhold capacity from the market, and
    3) the price is determined by a uniform (last accepted offer) price auction.
The results with six identical generators in the auction show 1) price spikes are common, and 2) average prices are higher than competitive levels. This confirms the belief that electricity markets with totally inelastic demand need more participants than typical markets to ensure competitive prices.
The second part of this paper describes experiments using four different types of auctions. In a “smart” market, the total cost of meeting load is minimized, subject to operating constraints, in all cases. The four auctions are:
    1) a uniform price auction with price inelastic load,
    2) a uniform price auction with price-responsive load,
    3) a discriminative auction in which generators are paid their actual offers instead of a uniform clearing price (commonly, and incorrectly, called pay-as-bid), and
    4) a “soft-cap” auction combining a uniform price and a discriminative auction.
The main result for all three groups of participants shows that both the uniform price auction (1) and the discriminative auction (3) produce average prices fifty percent above competitive levels. However, the prices for the uniform price auction are more volatile with many price spikes. The soft-cap auction (4) has price characteristics similar to the discriminative auction. In contrast, the uniform price auction with price-responsive load (2) has lower average prices (about thirty percent above competitive levels). The lower price volatility associated with the discriminative auction and the soft-cap auction is caused by the flatter offer curves in these auctions. However, this flat shape is likely to undermine the effectiveness of demand conservation as a way to reduce average prices. The uniform price auction with price-responsive load is the best among the four auctions tested, because it produces the lowest average price and has relatively low price volatility.
This paper was presented at the Rutger's Center for Research in Regulated Industries 14th Annual Western Conference: Advanced Workshop in Regulation and Competition, Competitive Change in Network Industries, San Diego, California, June 2001. Revised draft: July 16, 2001. Uploaded: July 25, 2001.  
Timothy D. Mount, William D. Schultze, Robert J. Thomas, Ray D. Zimmerman 07/25/01 2.39 MB PDF 01-18
Strong Resonance Effects in Normal Form Analysis and Subsynchronous Resonance
Power system normal form analysis has developed coefficients and indices in modal coordinates to quantify nonlinear model interactions. The coefficients can become very large near a strong, nondiagonalizable resonance occurring in the power system linearization. Moreover, the changes in the coefficients when the power system equations are expressed in different coordinates or units show that the coefficients are not intrinsic. On a different topic, the paper suggests an explanation for the modal interaction that causes the subsynchronous resonance instability in power systems. The modal interaction is associated with a pair of strong resonances which arise as a perturbation of a weak resonance of complex eigenvalues. This idea is supported using results from the IEEE first benchmark subsynchronous resonance model and perturbation theory. The normal form work in this IREP 2001 conference paper was supported in part by NSF and the PSERC controls project.
Bulk Power System Dynamics and Control V, August 26-31, 2001, Onomichi, Japan. Uploaded: July 3, 2001.  
Ian Dobson 07/03/01 316.88 KB PDF 01-19
Market Based Risk Mitigation
This document is a white paper based on a presentation given at a special workshop on infrastructre industry at the White House conference center. The workshop was organized and co-sponsored by OSTP and NSF. The paper outlines new risk management paradigms, in the context of critical infrastructre, that are enabled by the proliferation of information technology and the emerging restructuring of infrastructure industries.
Presented at a White House OSTP/NSF Workshop on Critical Infrastructure Interdependencies, June 14-15, 2001, Washington, DC. Uploaded: September 1, 2001.  
Shmuel S. Oren 09/01/01 95.55 KB PDF 01-20
Simulation of Top-Oil Temperature for Transformers
This Masters thesis describes a software tool TOTPS (top-oil temperature prediction system) developed to predict the top-oil temperature and maximum load a transformer is capable of carrying.
MS and Final report for PSERC project "On-Line Peak Loading of Substation Distribution Transformers Through Accurate Temperature Prediction: Simulation of Top-Oil Temperature for Transformers" (T-3), Daniel Tylavsky, Project Leader. Uploaded: May 23, 2002.  
Yong Liang 05/23/02 788.60 KB PDF 01-21
Transfer Capability Calculator and Tutorial
You can use this web site to:
    1. interactively calculate transfer capabilities on sample power systems and
    2. to browse tutorial and research material on transfer capability, particularly calculations involving sensitivity and uncertainty and generalizing DC load flow methods.
To operate the power system safely and to gain the benefits of the bulk power transfers, the transfer capabilities must be calculated and the power system operated so that the power transfers do not exceed the transfer capability. The calculation of transfer capability depends on many factors and the purpose of this web site is to explain and illustrate the calculation of transfer capability.
First Uploaded: January 23, 2002.  
Ian Dobson, Scott Greene, Rajesh Rajaraman, Fernando Alvarado, Chris Demarco, Ray Zimmerman, Mevludin Glavic, Antonio DeSouza, Bob Thomas et al. 01/23/02 URL 01-22
Examining criticality of blackouts in power system models with cascading events
As power system loading increases, larger blackouts due to cascading outages become more likely. We investigate a critical loading at which the average size of blackouts increases sharply to examine whether the probability distribution of blackout sizes shows the power tails observed in real blackout data. Three different models are used, including two simulations of cascading outages in electric power transmission systems. We also derive and use a new, analytically solvable model of probabilistic cascading failure which represents the progressive system weakening as the cascade proceeds.
Copyright 2002 IEEE. Hawaii International Conference on System Sciences, January 2002, Hawaii. Uploaded: September 28, 2001.  
Ian Dobson, Jie Chen, Jim Thorp, Ben Carreras, David Newman 09/28/01 437.71 KB PDF 01-23
Dynamics, criticality and self-organization in a model for blackouts in power transmission systems
A model has been developed to study the global complex dynamics of a series of blackouts in power transmission systems [1, 2]. This model has included a simple level of self-organization by incorporating the growth of power demand and the engineering response to system failures. Two types of blackouts have been identified with different dynamical properties. One type of blackout involves loss of load due to lines reaching their load limits but no line outages. The second type of blackout is associated with multiple line outages. The dominance of one type of blackouts versus the other depends on operational conditions and the proximity of the system to one of its two critical points. The first critical point is characterized by operation with lines close to their line limits. The second critical point is characterized by the maximum in the fluctuations of the load demand being near the generator margin capability. The identification of this second critical point is an indication that the increase of the generator capability as a response to the increase of the load demand must be included in the dynamical model to achieve a higher degree of self-organization. When this is done, the model shows a probability distribution of blackout sizes with power tails similar to that observed in real blackout data from North America.
Copyright 2002 IEEE. Hawaii International Conference on System Sciences, January 7-10, 2002, Hawaii. Uploaded: September 28, 2001.  
Ben Carreras, Vickie Lynch, Ian Dobson, David Newman 09/28/01 192.11 KB PDF 01-24
Power Systems Engineering Research Center
Abstract - This paper provides an overview of the Power Systems Engineering Research Center (PSERC), a National Science Foundation Industry/University Cooperative Research Center. PSERC’s mission is to produce innovative and effective solutions to challenges arising from the restructuring of the electric power business. There are thirteen participating universities, with over forty researchers and their students involved in multidisciplinary research projects. Projects are collaborative across universities and invite involvement from thirty industrial sponsors. Research focuses on three stems: markets, transmission and distribution technologies, and systems.

This description of PSERC was prepared for the 34th Annual Frontiers of Power Conference, Oct. 29-30, 2001, at Oklahoma State University.  
Ward Jewell and Dennis Ray 04/10/14 49.58 KB PDF 01-25
Using Weather Derivatives to Improve the Efficiency of Forward Markets for Electricity
The analysis in this paper demonstrates that a combination of:
    1) a forward contact, with fixed price for both base land and peaking power, and
    2) a collar option for the number of hot days in a summer is an effective way to reduce the risk of purchasing electricity in a spot market.
The main advantages are:
    1) the effectiveness of price signals is strengthened by making peaking power expensive, and
    2) the correlation between payouts from the weather option and high prices is increased.
Copyright 2002 IEEE. Published in the Proceedings of the Hawaii International Conference on System Sciences, January 7-10, 2002. Uploaded: October 24, 2001.  
Timothy D. Mount 10/24/01 127.45 KB PDF 01-26
Human Factors Aspects of Power System Voltage Visualizations
This paper presents experimental results associated with the human factors aspects of using color contours to visualize electric power system bus voltage magnitude information. Participants were divided into three groups: the first group only one-line numeric data, the second only one-line contour data, while the third saw both. The purpose of the experiment was to determine how quickly participants could both acknowledge low voltage violations and perform corrective control actions. Results indicated the contour only visualization resulted in the quickest voltage violation acknowledgements, while the numeric data only visualization resulted in the quickest solution times. Testing was done using a modified version of the IEEE 118 bus system.
Uploaded: October 25, 2001.  
Doug Wiegmann, Aaron Rich, Tom Overbye, Yan Sun 10/25/01 335.14 KB PDF 01-27
Analysis and Design of Power Acceptability Curves for Industrial Loads
The main objectives of this research are the analysis, extension, understanding and modification of the power acceptability curves (e.g., the Computer Business Equipment and Manufacturers Association or CBEMA curve and Information Technology Industry Council or the ITIC curve) to permit accurate application in the case of three phase loads.
This masters thesis also serves as a Final report for PSERC project "Redesign and New Interpretation of Power Acceptability Curves for Three Phase Loads: Analysis and Design of Power Acceptability Curves for Industrial Loads" (T-7) with Jerry Heydt, Project Leader. Uploaded: January 1, 2001.  
John Kyei 01/07/02 496.60 KB PDF 01-28
A Spectral Bisection Partitioning Method for Electric Power Network Applications
As an alternative to long-standing singular perturbation based coherency techniques, a spectral method for identifying groups of strongly connected sub-networks in a large-scale interconnected power system grid is presented. The method exploits concepts of the recursive spectral bisection (RSB) technique from the graph theory. Distinct from earlier works that have focused on partitioning dynamic models, here we will explore partitioning applications in the optimal power flow. This masters thesis is a work product of the New System Control Methodologies project.
MS thesis, Univ. of Wisconsin. Final report for PSERC project "New System Control Methodologies: Adapting AGC and Other Generator Controls to the Restructured Environment" (S-6). Uploaded: November 7, 2001.  
Supun Tiptipakorn 11/07/01 564.54 KB PDF 01-29
Mobile Agent Software Applied in Maintenance Scheduling
The deregulation in power systems brings some new issues in equipment maintenance scheduling where more coordination and communication among different entities is required. In this paper, the mobile agent software is applied in the facility maintenance scheduling in deregulated power systems environment. In the given example, the problem is de-coupled into a master problem and a sub-problem using Benders decomposition. The two problems are solved at the GENCO and the ISO respectively, and the mobile agent takes care of the communication and coordination between these two problem-solving processes.
Final report for PSERC project "Power System Monitoring Using Wireless Substation and System-Wide Communications" (T-11). Uploaded: November 19, 2001.  
Mladen Kezunovic, and Xiangjun Xu 11/19/01 84.24 KB PDF 01-30
An OPF based Algorithm to Evaluate Load Curtailment Incorporating Voltage Stability Margin Criterion
This paper proposes a method to compute load curtailment evaluation, using optimal power flow (OPF) computation, incorporating the steady state voltage stability margin constraints. A steady state voltage stability indicator is first discussed for its applicability as a suitable indicator for representing stability margin from the collapse point. The load curtailment formulation is then evolved and described into the OPF’s objective function. A criterion based on the voltage stability indicator is then incorporated as an additional constraint into the OPF. Examples are constructed to demonstrate the quantitative effects of the stability margin criterion in evaluating load curtailment.
Paper published in NAPS 2001, College Station, TX. Final report for PSERC project "Steady State Voltage Security Margin Assessment: Voltage Security Margin Assessment" (S-11). Uploaded: November 12, 2001.  
Garng M. Huang, Nirmal-Kumar C. Nair 11/12/01 440.50 KB DOC 01-31
Measurement Design and State Estimation for Distributed Multi-Utility Operation
With power market deregulation, companies cooperate to share one whole grid system but achieve their own economic goals. This paper focuses on how to improve the state estimation result of one company by exchanging raw or estimated data with other companies or ISO. First fundamentals to evaluate a measurement system are developed based on the concept of system redundancy index, leverage point and state estimation error variance. Then the investigations show the complexity of this interesting new topic. Accordingly a heuristic algorithm for the measurement design for distributed multi-utility operation is presented. The numerical results verify that data exchange does enhance the result of state estimation when some principles are applied.
Published in NAPS 2001, College Station, TX. Final report for PSERC project "Power System State Estimation and Optimal Measurement Placement For Distributed Multi-Utility Operation" (S-10). Uploaded: November 12, 2001.  
Garng M. Huang, Jiansheng Lei 11/12/01 344.00 KB DOC 01-32
On Completion Times of Networks of Concurrent and Sequential Tasks
Abstract - The problem of determining the time to complete multiple tasks that may proceed concurrently, sequentially, or both is considered. In the solution offered, each individual task completion time may be described with a number, interval, or distribution function. In the case of distribution functions, two task completion times might be independent random variables, as when the tasks are performed in different environments and proceed independently. Alternatively, completion times might be positively correlated, as when both depend on the quality of management and proceed within the same managerial environment, or they could be negatively correlated, as when resource sharing means that faster completion of one implies slower completion of the other. Finally, various factors might interact to make completion times dependent in a way that is difficult to characterize accurately. The solution offered avoids assuming that individual task completion times are independent or have any other dependency relationship. One application of the results is in project management, as in the context of PERT (Program Evaluation and Review Technique) diagrams.
Uploaded: November 13, 2001.  
Daniel Berleant, Lizhi Xie, Jianzhone Zhang, and Gerry Sheble 11/13/01 296.53 KB PDF 01-33
Electric Power Transfer Capability: Concepts, Applications, Sensitivity, Uncertainty
This report explains tutorial and research material on transfer capability, particularly calculations involving sensitivity and uncertainty and generalizing DC load flow methods. You can now use the web site associated with the document at to interactively calculate transfer capabilities on sample power systems. This report was produced by collaboration between PSERC and Laurits R. Christensen Associates as part of a project funded by the NSF Research Centers - Small Firms Collaborative R&D Initiative.
Uploaded: January 23, 2002.  
Ian Dobson, Scott Greene, Rajesh Rajaraman, Chris DeMarco, Fernando Alvarado, Mevludin Glavic, Jianfeng Zhang, Ray Zimmerman 01/23/02 1.46 MB PDF 01-34
Effects of Non-transposed Lines and Unbalanced Loads on State Estimation
This paper investigates the errors introduced in the positive sequence state estimation due to the usual assumptions of having fully balanced bus loads/generations and continuously transposed transmission lines. A three-phase state estimator is first developed in order to verify the actual error free solution in the phase coordinates. Then, several tests are conducted using different assumptions regarding the availability of single and multi-phase measurements. It is demonstrated that incomplete metering of three-phase system quantities may lead to significant errors in the positive sequence state estimates for certain cases. Such cases may also lead to incorrect bad data detection and elimination, further deteriorating the quality of the state estimate. IEEE 30 bus test system is used to illustrate these cases.
Final report for PSERC project "Enhanced State Estimation by Advanced Substation Monitoring" (T-9). Uploaded: November 19, 2001.  
Shan Zhong, Ali Abur 11/19/01 185.23 KB PDF 01-35
Electricity Supply Organization: Which End Is Up?
Instead of creating a top-down hierarchy for overseeing bulk power markets, the creation of four RTOs may end up inadvertently creating a smaller, decentralized generation structure. Will the new form fit its intended function, and how will it react to technological evolution within the industry?
White Paper. Uploaded: February 5, 2002.  
Richard E. Schuler 02/05/02 88.00 KB PDF 01-36
Mobile Agent Software Applied in Maintenance Scheduling
Abstract: The deregulation in power systems brings some new issues in equipment maintenance scheduling where more coordination and communication among different entities is required. In this paper, the mobile agent software is applied in the facility maintenance scheduling in deregulated power systems environment. In the given example, the problem is de-coupled into a master problem and a sub-problem using Benders decomposition. The two problems are solved at the GENCO and the ISO respectively, and the mobile agent takes care of the communication and coordination between these two problem-solving processes.
Uploaded: April 22, 2002.  
Xiangjun Xu and Mladen Kezunovic 04/22/02 84.24 KB PDF 01-37
Improving Circuit Breaker Maintenance Management Tasks by Applying Mobile Agent Software Technology
Abstract - Circuit breakers are crucial components for power system operation. The currently adapted time-directed maintenance strategy and the emerging new condition-based strategy require a flexible information processing technique and software architecture. In this paper, mobile agent software has been applied in implementing circuit breaker maintenance and repair tasks. Several potential application scenarios have been described and the relevant software features have been discussed. The benefits of using the mobile agent techniques are discussed at the end.
Uploaded: April 22, 2002.  
Mladen Kezunovic, Xiangjun Xu, and David Wong 04/22/02 119.12 KB PDF 01-38
Bluenet - a New Scatternet Formation Scheme
Bluetooth is a new promising local area wireless technology designed to enable voice and data communication among various electronic devices. We believe that Bluetooth networks will provide reliable, flexible and cost-efficient telecommunication support for the post-deregulation electric power systems. Though not specified in version 1.0 of the Bluetooth specification, communication by way of multi-hop routing (so characteristic of ad hoc networks) within a scatternet will offer a new and exciting extension to this technology. And the topology of such an ad-hoc scatternet would have a significant effect on the overall performance of the network. In this paper we present "Bluenet" as a novel and practical scheme for building an efficient scatternet and discuss the basic rules followed by the Bluenet scheme. Two methods are introduced to evaluate the performance of the resulting scatternets base on average shortest-path length and maximum traffic-flows respectively. Finally the effectiveness of the Bluenet scheme is demonstrated through simulations and comparison.
Copyright 2002 IEEE. Proceedings of the 35th Hawaii International Conference on System Sciences, January 7-10, 2002, Hawaii. Uploaded: March 11, 2003.  
Zhifang Wang, Robert J. Thomas, Zygmunt Haas 03/11/03 327.06 KB PDF 01-40
Multi-settlement Systems for Electricity Markets: Zonal Aggregation under Network Uncertainty and Market Power
We analyze alternative market designs for a multisettlement system for electricity in which the resolution of the transmission network model is increased as time approaches real-time, and uncertainty about congestion patterns is resolved. Variations of such systems are implemented or have been proposed in California and other parts of the U.S. We aim to compare welfare implications of such market designs against more centralized single-settlement systems, such as those implemented in the Northeastern control areas of the U.S. We model the multi-settlement system as a two-period game and compute subgame perfect Cournot-Nash equilibria for the various market designs.
Copyright 2002 IEEE. Proceedings of the Hawaii International Conference on System Sciences, January 7-10, 2002, Hawaii. Uploaded: March 11, 2003.  
Rajnish Kamat and Shmuel S. Oren 03/11/03 209.67 KB PDF 01-41
Post-Contingency Equilibrium Analysis of Power Systems
This paper presents alternative methods to compute the equilibrium condition immediately following a disturbance to an electric power system. The first uses the brute force method of simply integrating the dynamic model until it reaches steady state. The second uses the straightforward analytical choice of setting all time derivatives of the dynamic model to zero and solving the remaining algebraic equations for the equilibrium values of the dynamic states. This method requires the creation of new commercial software to solve the large-scale network algebraic equations simultaneously with the dynamic equilibrium equations. The third uses a method that takes advantage of existing commercial load flow software to perform the major portion of the solution process. These load flow solutions then iterate with the de-coupled algebraic equations for each generator.
Copyright 2002 IEEE. Proceedings of the 35th Hawaii International Conference on System Sciences, 2002, Hawaii. Uploaded: March 11, 2003.  
Peter W. Sauer 03/11/03 216.20 KB PDF 01-42
Spectral Analysis of Energy-Constrained Reserves
The definition of a service is key to the ability to meter it, measure it, regulate it, price it, or otherwise take it into consideration. Reserves (a form of power supply insurance) are key to power system operability. Traditionally, reserves have been characterized in terms of time domain quantities such as ramping rate capabilities and the like. Also, traditionally such measures have not considered the possibility that some of the reserve services may be energy or otherwise time-limited. This paper illustrates how to take into consideration energy constrained reserve services, and also how to classify and measure both the need for reserves as well as the ability to provide them in terms of frequency domain techniques. In a sense, the use of frequency domain quantities is more ?natural? for this problem where the characterization of the speed of response is in fact quite important. The paper illustrates a number of numerical examples.
Copyright 2002 IEEE. Proceedings of the 35th Hawaii International Conference on System Sciences, January 7-10, 2002, Hawaii. Uploaded: March 12, 2003.  
Fernando L. Alvarado 03/12/03 190.50 KB PDF 01-43
Testing The Effects Of Price Responsive Demand On Uniform Price And Soft-Cap Electricity Auctions
Testing auction mechanisms experimentally in a controlled environment provides an inexpensive means for evaluating their relative merits. This paper describes a framework for testing the efficacy of a price-responsive load on a uniform price last accepted offer and a soft-cap market. Experimental evidence to date based on uniform price market testing has shown an ability of price responsive load to mitigate high volatility and average price. The paper addresses a process to validate these results as well as our hypothesis that price responsive load will mitigate high soft cap market price behavior such as that observed in California.
Copyright 2002 IEEE. Proceedings of the 35th Hawaii International Conference on System Sciences, January 7-10, 2002, Hawaii. Uploaded: March 11, 2003.  
Robert J. Thomas, Timothy D. Mount, Ray Zimmerman, William D. Schulze, Richard E. Schuler, L. D. Chapman 03/11/03 351.01 KB PDF 01-44
Visualization and Animation of Inverter-Driven Induction Motor Operation
This paper discusses a new model of an inverterdriven induction motor that enables direct animation and visualization of the inverter and motor operation. The models of the inverter and induction motor are physically based model in actual quantities. As such they enable direct animation and visualization of the operation of the inverterdriven induction motor. The paper discusses the models and the animation and visualization approach. Specifically, the animation and visualization screens are discussed in terms of the displayed information. The implementation is in Open GL that permits rendering as well as rotation, panning, and zooming in real time. The paper presentation is by means of a live presentation of the animation and visualization models.
Copyright 2002 IEEE. Proceedings of the 35th Hawaii International Conference on System Sciences, Hawaii. Uploaded: March 11, 2003.  
A. P. Sakis Meliopoulos, George J. Cokkinides 03/11/03 400.64 KB PDF 01-45
Real Time Digital Processing of GPS Measurements for Transmission Engineering
The focus of this paper is on the digital signal processing (DSP) of differential GPS (DGPS) measurements. The paper describes a methodology for further improving DGPS altitude measurements for the purpose of accurate determination of high voltage overhead conductor sag. The wavelet transforms and least squares parameter estimation (LSPE) techniques are considered.
The Global Positioning System (GPS) is a state of the art timing and positioning system based on 24 or more satellites launched and maintained by the United States government. Power engineering applications based on the GPS include phasor measurement, positioning applications such as surveying and mapping, and potentially in deriving real time data on transmission lines that will allow them to be loaded to a dynamic (thermal or security) limit. Inherent errors in GPS technologies are discussed, and the differential GPS method is described for accuracy enhancement. Further digital processing needs are necessary for meeting the accuracy requirements of certain specific applications. The focus of this paper is on the digital signal processing (DSP) of differential GPS (DGPS) measurements. The paper describes a methodology for further improving DGPS altitude measurements for the purpose of accurate determination of high voltage overhead conductor sag.
Last Edited: October 25, 2001. Updated: April 5, 2003.  
Chris Mensah-Bonsu, and Gerald T. Heydt 04/05/03 238.18 KB PDF 01-46
A Phase-Transition Model for Cascading Network Failure
As the scale of engineered systems such as electric power grids, communication networks, and the internet expands, and as society's dependence upon reliable operation of these networks increases, it is vital that system engineers seek a better understanding of how small scale failures of individual elements may propagate to produce global, system-wide failures. In a deterministic model, we seek to capture the role of transient dynamic response following a specified initiating disturbance and examine subsequent ("cascading") element failures that are induced when operating thresholds for individual elements are exceeded along the state trajectory.
Copyright 2001 IEEE. IEEE Control Systems Magazine, pp. 40-51, December 2001. Uploaded: August 27, 2003.  
Christopher L. DeMarco 08/27/03 8.50 MB PDF 01-47
The FGR vs. FTR debate: Facts and Misconceptions
Comments on "Electricity Market Design and Structure", 2001. This note comments on the section concerning the definition of transmission rights in FERC’s working paper on Standardized Transmission Service and Wholesale Electric Market Design. The comments below endorse the following positions
    1. Support FERC’s recommendation to use of flowgate rights in conjunction with point to point rights for hedging congestion cost.
    2. Recommend that point to point rights (FTRs) be defined only as two sided financial instruments and not be offered as options.
    3. Recommend that flowgate rights (FGRs) be offered only as one sided instruments (options for the buyer and obligation for the seller).
The comments are also intended to clarify a number of misconceptions surrounding the FGR vs. FTR debate.
Comments in 2001 on FERC Docket No. RM01-12-000 (Electricity Market Design and Structure). Uploaded: September 20, 2005.  
Shmuel S. Oren 09/20/05 220.33 KB PDF 01-48
State Estimation for the Detection of Market Parameters
Deregulation of electric utilities has led to a new competitive regime for utilities. In traditional systems, the main objective is to estimate voltages and flows. Estimators that include the ability to determine system parameters along with system (conditions have been developed. In the evolving deregulated environment there are a host of new estimation needs. The various costs of the participants, estimation of the degree of market power, estimation of the price elasticities of the participants, and estimation of the volatilities of prices. This paper addresses two estimation needs. It defines the problem of estimation system status based on the knowledge of published PTDFs (Power Transfer Distribution Factors) by describing a new procedure for estimating parameters It also reformulates a previously presented but not much publicized method for estimating the cost elasticities of generators.
IEEE/PES Summer Meeting, Vancouver, British Columbia, Canada, July 16, 2001. Uploaded: September 26, 2005.  
Fernando L. Alvarado 09/26/05 1.10 MB PDF 01-49
Kirchhoff vs. Competitive Electricity Markets: A Few Examples
While nearly everyone points to deregulation, spiking electricity prices, rolling blackouts, potential utility bankruptcies and generator greed, the fundamental problem with electricity supply is being unable to decide how to decide about siting new generation and transmission facilities, Because of enormous public impacts, these are properly public decisions. And so it is government that should live up to its responsibilities in facilitating decisions on proposed new facilities. But even expeditious action today will not bring additional capacity on line for at least two, more likely, four years. Beyond that, we need to check on the adequacy of gas pipeline capacity, turbine-generator manufacturing capability and gas exploration rates.
Copyright 2001 IEEE. IEEE Power Engineering Society Winter Meeting 2001, vol. 3, pp. 1256-1261. Uploaded: June 27, 2006.  
Carlos E. Murillo-Sanchez, Ray D. Zimmerman, Robert J. Thomas 06/27/06 871.17 KB PDF 01-50
Aligning Public Policy with Electricity Markets
While nearly everyone points to deregulation, spiking electricity prices, rolling blackouts, potential utility bankruptcies and generator greed, the fundamental problem with electricity supply is being unable to decide how to decide about siting new generation and transmission facilities, Because of enormous public impacts, these are properly public decisions. And so it is government that should live up to its responsibilities in facilitating decisions on proposed new facilities. But even expeditious action today will not bring additional capacity on line for at least two, more likely four, years. Beyond that, we need to check on the adequacy of gas pipeline capacity, turbine-generator manufacturing capability and gas exploration rates.
IEEE Power Engineering Society Summer Meeting, British Columbia, Canada, 2001, vol. 1, pp. 555-557. Uploaded: June 27, 2006.  
Richard E. Schuler 06/27/06 390.76 KB PDF 01-51
Visualization and Animation of Protective Relay Operation from DFR Datat
DRF data are useful for post mortem analysis of system disturbances. Central to this problem is the response of relays to disturbances. This paper presents an improved method for post-mortem analysis of relay response to disturbances from DFR data. Specifically, a visualization application for the operation of protective relays using digital fault recorder data is presented. The visualization is implemented with animated display objects attached on a general purpose DFR data display and analysis package (XFM). The visualization objects illustrate the evolution of relay variables that are used to determine the tripping logic. Two examples of protective relay types are presented: (a) a modified mho relay and (b) a transformer differential relay. This tool is extremely valuable for educational purposes. Another potential application is digital relay testing. Actual digital relay algorithms can be interfaced to the visualization objects, yielding a flexible testing tool for the plethora of relays and relay manufacturers.
Proceedings of the 2001 Georgia Tech Fault & Disturbance Analysis Conference, Atlanta, GA. Uploaded: June 30, 2006.  
A.P. Sakis Meliopoulos and George J. Cokkinides 06/30/06 551.49 KB PDF 01-52