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No FOLDERS found.   Sort by:   Number   Name Author Date Size Type 05-02 Phasor 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. Mark Rice and Gerald T. Heydt 4/27/2005 1.0M PDF 05-04 On-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. Vijay Vittal, Project Leader 5/10/2005 630.5k PDF 05-13 Comprehensive 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. Sakis Meliopoulos, Project Leader 9/8/2005 2.0M PDF 05-14 Distribution 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. Sakis Meliopoulos, Project Leader 9/8/2005 1.9M PDF 05-36 Estimation of Synchronous Generator Parameters from On-line Measurements This is the final report on a research project on identification of synchronous machine parameters using on-line measurements. The concept is to utilize the dynamic operational data in combination with manufacturers’ estimates of synchronous machine parameters to ‘force’ the machine model to agree with measurements. Park’s model is used with three damper windings. The method uses a mathematical tool from state estimation technology to formulate a minimum squared error solution. A particular difficulty relates to modeling magnetic saturation. A combination of classical model with a new approach is used so that saturated and unsaturated data are calculated. The mathematical details are given in equations and flow charts. Also, the method has been programmed in an object-oriented Graphic User Interface (GUI) in which the user attaches the machine measurement data file, and manufacturers’ estimates. The calculation is displayed on a GUI menu. The method has been tested with data from approximately six large generating units (all machines with field circuit brushes). Estimates of model resistances and unsaturated inductances agree with manufacturers’ estimates as well as operating data. The authors conjecture that the parameters calculated in this way actually may be more accurate for the given operating conditions than the manufacturer’s parameters which may have been obtained from stand-still tests many years ago. This is the final report for project S-15 "Extended State Estimation for Synchronous Generator Parameters". Draft received May 24, 2005. Final report uploaded June 7, 2005. Gerald T. Heydt, Project Leader 1/22/2006 1.6M PDF 05-37 Software Agents for Market Design and Analysis Software agents can be of help in the design, analysis and verification of markets. The agents described in the four chapters of this report do two things. First, they identify some of the uses of software agents. Second, they show that competitive behavior is not guaranteed for existing electricity auctions. Rather, suppliers can drive prices to well above competitive levels and make excessive profits. Chapter-1 covers software agents designed to mimic test-results obtained from human subjects in simulated electricity markets. Chapter-2 covers the use of a multi-agent system (MAS) to simulate a spot market with several supply firms. Chapter-3 investigates how spot prices are affected by forward contracts. Experimental economics and agent-based simulations are used. Chapter-4 uses software agents to examine repeated auctions. The purpose of the agents is not to mimic the behavior of humans. This is the final report for the project "Bidding Agents" (M-5). Initial Draft Received: 6/3/2005. Final Report Uploaded: 6/17/2005. Sarosh Talukdar, Project Leader 11/20/2005 953.2k PDF 05-55 Market 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. Shmuel Oren, Project Leader 1/22/2006 121.2k PDF 05-56 Enhanced 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 leader 1/22/2006 2.9M PDF 05-57 Enhanced 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 Abur 1/22/2006 532.8k PDF 05-58 Optimal 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 leader 1/22/2006 239.4k PDF 05-59 Detection, 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 Zhang 1/22/2006 1.1M PDF 05-60 Detection, Prevention and Mitigation of Cascading Events: Part II Recent blackout events (such as the 1996 Western U.S. events, the 2004 Northeastern disturbance, and the 2004 Italian blackout) have demonstrated the need for new automatic controllers that respond to unforeseen operating conditions to keep power system problems from cascading into large-scale blackouts. One way to prevent, slow or mitigate large-scale outages is to monitor and control the effects of instability events in large electric power systems. This research produced a real-time centralized controller that addresses small-signal stability events that could initiate a cascade leading to a large-scale outage. The controller is central to a proposed real-time, wide-area control strategy that detects and mitigates small-signal stability phenomena as they emerge. In essence, the strategy uses the controller to provide a safety net for the power system. Simulations showed that the controller could have stabilized oscillations before they became critically large in the Western U.S. blackout on August 10, 1996. This is Part II of the final report for the PSERC project "Detection, Prevention and Mitigation of Cascading Events" (S-19). Draft received: Nov. 9, 2005. Final report uploaded: Nov. 28, 2005. Vaithianathan “Mani” Venkatasubramanian and Jaime Quintero 2/23/2006 1.3M PDF 05-61 Detection, Prevention and Mitigation of Cascading Events:Part III Among the various system control strategies, controlled system islanding is the final resort to save a system from a blackout. In the literature, many approaches have been proposed to undertake controlled islanding. Some approaches only take static power flow into consideration; others require a great deal of computational effort. Following large disturbances, groups of generators tend to swing together. Research has focused on control strategies to maintain stability of inter-area oscillations between groups of machines. The slow coherency-based generator grouping is one potential method for capturing the movement of generators between groups under disturbance. The research issue is how to take advantage of the information from the slow coherency generator grouping method to island the system in a controlled way by tripping an identified set of transmission lines. In this third part of the final project report, a comprehensive approach is proposed for controlled islanding. The approach uses slow coherency based generator grouping to initiate controlled power system islanding based on the minimal cutset technique from graph theory by calculating the net flow through the cutset. The proposed approach has been demonstrated on a 29-generator, 179-bus model of the WECC system. This is Part III 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. Vijay Vittal and Xiaoming Wang 1/22/2006 975.2k PDF 05-62 New Implications of Power System Fault Current Limits Increasingly power system operators and planners are realizing that fault current analysis needs to play a broader role in operating practices, and in planning policies and decisions. For example, maximum fault current levels may constrain operations and impose limits on generation siting. Also, new ways of operating power systems and new installed gen-eration sources are changing the fault response of power systems in unanticipated or un-appreciated ways. In part, these changes may have been brought about by market forces in power systems that resulted in greater reliance on interconnections for power transactions. But at the distribution level, it is the entry of new generation sources, such as co-generation, distributed generation, and unconventional generation (such as electronically-controlled fuel cells and wind generators) that has motivated reexamination of the purposes and tools of fault current analysis. This project has explored how fault currents in distribution systems are being affected by new generation sources, new tools for fault analysis, and implications of increased fault currents on protection systems. In particular, the research focused on (1) Changes in maximum fault currents due to new and alternative generation siting; (2) Online assessment of fault current; (3) Security-constrained optimal power flow studies with fault current as a constraint; (4) Interruption of maximum circuit currents; (5) Three-phase analysis; and (6) Effects of new fault current levels on circuit breaker topology and on operating limits. This is the final project report for the PSERC project "New Implications of Power System Fault Current Limits" (project S-20). Draft submitted: August 2005. Final Report Uploaded: October 17, 2005. G.T. Heydt, Project Leader 1/22/2006 3.4M PDF 05-63 Effects of Voltage Sags on Loads in a Distribution System Voltage sags pose a serious power quality issue for the electric power industry. Much work has been done assessing the effects of voltage sags on power system operation, and on industrial and commercial loads. However, more research has been needed on the effects of voltage sags on residential loads, particularly sensitive equipment such as computers. This project helps fill that information gap by providing new detailed information on the effects of voltage sags of varying depths and durations on selected residential equipment. In addition, to better understand how voltage sags affect the residential customer class, surveys were conducted to determine the type of equipment present in residential apartment complexes in Tempe, Arizona. With testing and survey data, it was possible to develop predictions of the overall effect of voltage sags of various depths and durations on selected apartment complexes. Finally, the testing enabled assessment of the accuracy of standard “CBEMA” curves that allow prediction of the effect of voltage sags on equipment performance. Tests performed on selected residential equipment suggest that voltage sags tend to not damage the equipment. Tests were conducted on contactors, circuit breakers, air conditioner compressors, helium and fluorescent lamps, computers, microwave ovens, televisions, VHS/DVD players, CD players, digital clock radios, sandwich makers, and toasters. This is the final project report for the PSERC project "Effects of Voltage Sags on Loads in a Distribution System" (project T-16). Draft submitted: September 2005. Final Report Uploaded: October 29, 2005. George Karady, Project Leader 2/23/2006 3.1M PDF 05-64 New System Control Methodologies: Adapting AGC and Other Generator Controls to the Restructured Environment As the US moves towards competitive markets in electric power generation, the shift of ownership and operational control of generation from the vertically integrated utilities to independent, for-profit generation owners has raised a number of fundamental issues regarding grid control. Questions concerning appropriate generator control loop functionality to meet grid-wide objectives, while simultaneously enabling full profit potential for individual generator owners, have not been fully answered more than a decade into North America’s experience in electric utility restructuring. Generators remain the fundamental control resource for achieving system-wide frequency regulation, stable electromechanical dynamic response, and, to a lesser degree, voltage control. In working toward appropriate functionality, the goal should be to develop practical generator feedback controls that maximize a generator's contributions to the system-wide control objectives while minimally conflicting with that generator’s profit-making, energy production activities. Remaining issues relate to the creation of generator control designs that are more appropriate to the new operational objectives of a restructured power network. Generator control designs needs to address (1) regulation of bilateral transactions, (2) the interplay of generation controls with grid congestion management, and (3) the need for large numbers of distributed, potentially intermittently-connected generators to “do no evil” with respect to stable, system-wide electromechanical response. In this project, we modified the traditional “Automatic Generation Control (AGC)” to accommodate bilateral transactions. This is the final report for the project New System Control Methodologies” (PSERC project S-6). Uploaded: Nov. 22, 2005. Christopher L. DeMarco, Project Leader 2/23/2006 6.9M PDF 05-65 Visualization of Power Systems and Components This report, along with the related publications, present results from the PSERC “Visualization of Power Systems and Components” project. The research focused on (1) the development and/or enhancement of techniques for visualizing power system information, (2) the development of techniques for visualizing power system component information, and (3) performing human factors experiments and analysis on the visualizations developed in the project. The specific results from the project can be grouped into four areas. First, the project developed enhanced two-dimensional (2D) power system visualizations. Second, the project demonstrated the use of 3D displays to show the geographic relationships between the contingencies causing violations and the violated elements. Third, the project demonstrated how system wide overview visualizations could be supplemented with visualizations of the detailed status and operating conditions of important power system devices. Last, the project focused on the performance of formal human factor experiments to evaluate the effectiveness of power system visualizations. This is the final report from the "Visualization of Power Systems and Components" project (PSERC project S-18). Uploaded: Nov. 23, 2005. Thomas J. Overbye, Project Leader 2/23/2006 5.8M PDF

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