Implementation of Synchrophasor Monitoring at Entergy: Tools, Training and Tribulations
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Floyd Galvan, PE, Member, IEEE, Ali Abur, Fellow IEEE, , Kai Sun, Member, IEEE, Mark Thomas, Member IEEE, Vaithianathan Venkatasubramanian , Member. IEEE and Rubal, KC
Abstract--Entergy, through its American Recovery and Reinvestment Act - Smart Grid Investment Grant, is leveraging the achievements and experience of their existing prototype phasor system and creating a new wide-area monitoring system with advanced decision support tools and visual graphics to assist in the management and surveillance of the Entergy grid. This paper introduces the topics for presentation at the PES General Session: 1) the decision support tools being implemented, including the challenges and risks associated with data quality and timely delivery; 2) the training and education being instituted for the formation of the foundational knowledge base required to implement these tools; and 3) the challenges we face in the wide-area deployment and integration of these decision support tools. Additional topics that will be introduced are: phasor data storage and retrieval; visualizations for the advanced software applications; and the metrics being designed to measure the success of these new tools. Index Terms--phasor measurement units, power engineering education, stability analysis, state estimation, voltage measurement, wide-area measurements
I. INTRODUCTION
E
NTERGY,
through
its
American
Recovery
Reinvestment Act (ARRA) Smart Grid Investment Grant (SGIG), is implementing an enhanced transmission This material is based upon work supported by the Department of Energy under Award Number(s) DE-OE0000375. Disclaimer: This paper was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Floyd Galvan is with Entergy Corporation, Gretna, LA 70131 (e-mail:
[email protected]). Ali Abur is with Northeastern University, Boston, MA, 02115 (e-mail:
[email protected]) Kai Sun is with the Electric Power Research Institute (EPRI), Palo Alto, CA 94304 (e-mail:
[email protected]) Mark Thomas is with Entergy Corporation, Pine Bluff, AR 71602-5061 USA (e-mail:
[email protected]) Vaithianathan "Mani" Venkatasubramanian is with School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA 99164-2752 (
[email protected]) Rubal KC is with Entergy Corporation, Pine Bluff, AR 71602-5061 (e-mail:
[email protected])
978-1-4673-2729-9/12/$31.00 ©2012 IEEE
monitoring system for the real-time surveillance of the widearea grid with the use of synchrophasor measurement units (PMUs). PMUs are devices that use synchronization signals from the global positioning system (GPS) satellites and provide the positive sequence phasor voltages and currents measured at a given substation. This paper introduces the following presentation topics that will be discussed at the general session: 1) decision support tools, 2) training and education program, and 3) the challenges of deploying new technologies in the electric utility industry. II. DECISION SUPPORT TOOLS In order to take advantage of synchrophasor technology, Entergy is implementing real-time oscillation and voltage stability monitoring systems. In addition, a synchrophasor enhanced state estimator is being developed. These tools, discussed in more detail below, provide a new wide-area monitoring system with advanced decision support tools and visual graphics. A. Oscillation Monitoring System and Voltage Stability Monitoring System Oscillation Monitoring System (OMS) and Voltage Stability Monitoring System (VSMS) applications developed by the Washington State University (WSU) are aimed at ensuring operational reliability of the Entergy power system by reducing the risks towards unforeseen loss of customer loads, especially under severe operating conditions and emergence of sudden stability problems. OMS estimates the mode frequency, mode damping ratio and mode shape of poorly damped electromechanical oscillatory modes seen in available Entergy PMU measurements. By detecting and mitigating poorly damped or negatively damped oscillations, the OMS will also help improve power quality. Poorly damped oscillatory modes, if left uncorrected, can affect power quality. If poorly damped oscillations persist over a period of say thirty minutes, they can also lead to generator rotor fatigue; thus reducing the lifespan of expensive power system equipment. If the oscillatory modes become negatively damped, the problem becomes more severe. Negatively damped oscillations, if uncorrected, can lead to tripping of major generating units and loads from the power grid, potentially leading to system islanding and partial blackouts within Entergy. The introduction of diverse new generation facilities, such as wind farms with complex power electronic controls, as well as continuing growth of system loads introduce operational uncertainty in terms of how the power system modes will evolve in the future. OMS provides the ideal platform for the future by continuously monitoring the oscillatory modes
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automatically from PMU measurements so that emerging problems can be detected in the early stages. VSMS estimates the voltage security status of PMU monitored substations in Entergy system. Voltage instability phenomenon is caused by lack of adequate reactive power support in some part of the system. Voltage instability can be caused by sudden loss of multiple transmission lines, a typical problem for Entergy during the summer storm seasonal months, and/or, excessive unforeseen reactive power demands from loads. If left uncorrected, voltage instability can lead to partial blackouts in the stressed part of the system. Moreover, voltage collapse, if it persists, can even spread to geographically widespread regions by drastically affecting regional tie-line flows, as was seen during the 2003 northeastern blackout. It is important to detect the proximity of system operation towards voltage instability so that operators can be alerted to take appropriate actions to correct the problem well-in-advance. The OMS and VSMS applications reside within an openPhasor Data Concentrator (openPDC) developed by Grid Protection Alliance (GPA). The openPDC collects Entergy PMU data from substations and streams time-aligned Entergy PMU data to WSU’s applications using IEEE C37.118 protocol. The applications output results into files periodically (approximately every ten seconds) that are consumed by a Space-Time-Insight (STI) developed application that generates visual displays. The visualizations can then be accessed by Entergy engineers and operators to help manage the operation of the power system against the emergence of sudden oscillation and voltage stability problems. B. Measurement Based Voltage Stability Assessment The Electric Power Research Institute (EPRI) has developed a Measurement Based Voltage Stability Assessment (MB-VSA) application that is improving system operators’ real-time awareness of voltage stability by utilizing a mix of both Energy Management System (EMS) and synchrophasor data. Voltage Stability Assessment (VSA) is a key function in system operation to help operators foresee the next critical contingencies that will cause system-wide instability problems. Currently, VSA programs rely on the state estimator (SE) to provide steady-state solution for further analysis. When the system is close to operating limit, the system estimator may fail to converge; therefore it cannot provide a steady-state solution for online VSA. Having recognized the limitations of traditional voltage stability analysis methods, the challenge now is whether substation level measurements can be used to calculate voltage stability margin in real-time and provide adaptive margin information for operators to monitor and control system voltage stability. The objective EPRI’s MB-VSA application is to improve system operators’ real-time awareness of voltage problems in Entergy’s Western region by utilizing a mix of both Energy Management System (EMS) and synchrophasor data. EPRI’s application is installed at the Entergy Synchrophasor application server. An interface between the application and Entergy’s data server was developed to collect the EMS and synchrophasor data at several identified substations
continuously. The calculated voltage stability margin is then sent back to the data server and displayed on a designated computer screen at Entergy’s control center through STI visualization tool for system operators to monitor the voltage stability condition of the Western Region system. C. SynchroPhasor Assisted State Estimator The SynchroPhasor Assisted State Estimator (SPASE) application, developed by Northeastern University (NEU), is expected to play a key role in power system operation. Traditional State Estimation (SE) is used to provide optimal estimation of current power system states based on the received measurements and network topology. One of the essential state variables in SE is the bus voltage phase angle. However, this information was based on calculation and not directly measured until synchronized phasor measurements were available to provide more precise measurements of the phase angles. The SPASE application is being implemented benchmarked and tested as part of this project and is being used to help determine optimal locations for installing new PMUs at critical locations. SPASE is able to accept conventional measurements as well as synchronized phasor measurements. Note that SPASE accepts both voltage and current phasor measurements, unlike currently available SE packages. Network observability analysis and the identification of observable islands can be made. In addition, SPASE can optimally place pseudomeasurements, from a list of available pseudo-measurements, in order to merge observable islands without introducing any redundant pseudo-measurements. SPASE can identify all critical measurements in the system, provide a list of critical measurements whose bad data cannot be detected, and process measurements to detect and identify bad data. A STI visualization application is used so that observable islands, critical measurements, and identified bad data are clearly visualized for control center operators. Visualization of these items has not been part of commercial State Estimator features in the past. It is expected that such visualizations will enhance operators’ situational awareness in the control centers. D. Operator Decision Tool Deployment Entergy is implementing a deployment plan for the decision support tools discussed above. The initial phase of the project includes validating and fine tuning the synchrophasor applications based on historical phasor data. Subsequent phases will include extended field testing, review of field trial information by external university consortiums and the training and education of Entergy personnel on these new tools. III. ENTERGY’S TRAINING AND EDUCATION PROGRAM Education and training will play a critical role in the successful deployment of synchrophasor technology and the supporting analytical software solutions. Business value can only be realized by dedicated trained resources that target the use of real-time PMU information and visualizations for better
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understanding and interpretation of wide-area disturbances. As such, Entergy is deploying a comprehensive Training and Education Program (T&EP) to help achieve and sustain the expected benefits of this investment and provide common core standards of education and training on synchrophasors. The goal of the T&EP is to provide an educational foundation on synchrophasor technology to allow the operator and engineer to actively engage this technology in their daily work activities. This goal will be realized through the training of operators and engineers in the effective use, and ultimately, acceptance, of real-time PMU information and visualizations to better understand and interpret wide-area disturbances. Training seeks to increase the operators understanding of Entergy’s phasor infrastructure and state-of-the-art operational decision-making tools. Engineers will be trained in the management and operation of the PMU infrastructure. In addition, extended beta testing and demonstration of the new analytics is being undertaken prior to introduction to real-time operational use. Model-based simulations are also being carried out to take full advantage and validate the significance of the data this technology is providing. Specifically, the T&EP includes: 1) Education of engineering support staff and area planners on the algorithms being used for synchrophasor visualizations and the interpretation of their outputs. 2) Integration of phasor information into baseline planning studies. 3) Use of phasor information in post-mortem event analysis and model improvements. 4) Training of field technicians to support the testing and maintenance of PMU hardware and software systems installed in the field. In 2011, training focused providing a general introduction to synchrophasor technology to over 600 Entergy transmission employees through the use of interactive, web-based, eLearning series of modules. In addition, field technicians were trained in testing and maintenance of specific PMU hardware and software and switches. For 2012, training is focusing on IT configuration and administration support, field technicians in testing and maintenance of PMU hardware, and continued general education through the creation of “The Entergy Phasor Project Documentary - The Next Evolution in Energy, Part 1”. Engineers will also be provided more detailed, WebEx training for analysis, visualizations and baseline planning studies. Year 2013 will continue training and education in configuration and administration support and engineers in the analysis, visualization, and baseline planning studies. During this year, operators will be trained on how to integrate real-time PMU information and wide area visualization into daily work activities, field technicians will continue training for testing and maintenance of PMU hardware , and – “The Entergy Phasor Project Documentary The Next Evolution in Energy, Part 2” presenting the results of the project will be rolled-out to Entergy transmission employees. Education and training will continue to play a critical role in successful deployment of phasor measurement technology
and supporting analytical software solutions beyond the threeyear project. The T&EP will lead to the development of a sustainable learning environment at Entergy to continually extend and reinforce the application, education and benefits of synchrophasor technology IV. CHALLENGES OF DEPLOYING NEW TECHNOLOGIES IN THE ELECTRIC UTILITY A. Paradigm shifts in Technology Synchrophasor technology is still maturing and developing. This means PMUs being installed today may quickly become obsolete and changes have to be continually integrated to the system architecture and control design. In addition, industry standards do not currently exist for many of the phasor measurement and phasor data concentrator technologies. This makes the standardization and testing of this equipment at a utility very challenging. The development of standards by such organizations as IEEE, IEC and NIST are helping to solidify the role of PMU and PDC technology in the industry and the level of required cyber security. In the interim, utilities have to diligently monitor industry best practices and shifting legal and regulatory requirements. B. Cyber Security Electric utilities are increasingly more vulnerable to cyber break-ins and attacks. This is in part due to the deployment and integration of new technologies into Industrial Control Systems (ICS) environments formerly secured by private and proprietary networks. New technologies support interoperable protocols enabling control systems to connect to corporate networks, the Internet and third-party networks and computing environments. Along with the ability to share resources, streamline processing and easily interface to legacy systems and applications comes new threats and vulnerabilities. Most vendors are lagging behind in providing cyber security solutions and at best are only providing spot and vendor-specific solutions that do not integrate well to other vendor products and legacy systems. Industry standards and best practices continue to evolve, further contributing to a “wait and see” posture on behalf of vendors and their utility customers. A. Abbreviations and Acronyms ARRA American Recovery and Reinvestment Act DOE Department of Energy EMS Energy Management System ENTERGY Entergy Corporation EPRI Electric Power Research Institute GPA Grid Protection Alliance ICS Industrial Control Systems MB-VSA Measurement-Based Voltage Stability Assessment NEU Northeastern University OMS Oscillation Monitoring System OPENPDC openPhasor Data Concentrator OSI Pi OSIsoft Pi Historian PMU Phasor Measurement Unit
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SE SGIG SPASE STAS STI T&EP VSA VSMS WSU
State Estimator Smart Grid Investment Grant SynchroPhasor Assisted State Estimator Space-Time Awareness Server Space-Time Insight Training and Education Program Voltage Stability Assessment Voltage Stability Monitoring System Washington State University V. ACKNOWLEDGMENT
The author gratefully acknowledges the contributions of the Department of Energy, Entergy Corporation, and the Entergy Phasor Project Team. VI. BIOGRAPHY Floyd Galvan, PE, (M’81). Mr. Galvan is the Program Manager for the Entergy Services Inc. (ESI)/Department of Energy (DOE) Smart Grid Investment Grant Phasor Project. Mr. Galvan leads Research & Development at Entergy, with specializations in phasor measurements, grid control and visualization, applications for wide-area monitoring, long-term planning and regional energy pricing. Mr. Galvan has worked throughout the industry in various areas including system planning, fuels procurement and wholesale energy He has held leadership positions forecasting. within the North American SyncroPhasor Initiative (NASPI), the Power Systems Engineering Research Center (PSERC) and the CEATI Power Systems, Planning and Operations committee. He has served on numerous panels and committees at the National Science Foundation, National Institute of Standards and Technology (NIST), and the Department of Energy and has spoken widely throughout the U.S. and Internationally. Mr. Galvan was recently awarded one of the DOE Smart Grid Investment Grants to implement the Entergy Phasor System; in November 2011 Mr. Galvan was awarded the EPRI Power Delivery & Utilization (PDU) Technology Transfer Award for collaborating with EPRI to successfully demonstrate the benefits of using measurement based voltage stability monitoring to improve the situational awareness of system operators. In 2007 he won the T&D Utility and Automation Magazine Project of the Year Award for the prototype Entergy Phasor Project, and he has been the lead author of multiple articles in leading electric industry publications. Mr. Galvan is a licensed Professional Engineer in the State of Texas. He received a B.S. in Electrical Engineering from Texas A&M University-Kingsville and a Masters of Liberal Arts from Southern Methodist University with a focus in Art History. Mr. Galvan is a long-time resident of New Orleans, LA. Ali Abur (F’03) received the B.S. degree from Orta Dogu Teknik Universitesi, Ankara, Turkey, in 1979 and the M.S. and Ph.D. degrees from The Ohio State University, Columbus, in 1981 and 1985, respectively. He was a Professor at the Department of Electrical Engineering, Texas A&M University, College Station, until November 2005, when he moved to Northeastern University, Boston, MA, as the Chair of the Electrical and Computer Engineering Department. His research interests are in computational methods for the solution of power system monitoring, operation, and control problems.
Kai Sun (M’06) received the B.S. degree in automation and the Ph.D. degree in control science and engineering from Tsinghua University, Beijing, China, in 1999 and 2004, respectively. He was a postdoctoral fellow at the University of Western Ontario in London, Ontario in 2005 and a research associate at Arizona State University in Tempe, Arizona from 2005 to 2007. He is currently a project manager at the Electric Power Research Institute (EPRI) in Palo Alto, CA in the areas of grid operations, planning and renewable integration. His research interests include power system stability, dynamics and control, and complex networked system analysis and optimization. Mark Thomas received a BSEE degree from Louisiana Tech University and a MBA degree from the University of Phoenix. He is a licensed professional engineer in Arkansas. Mark is the Manager of Transmission Security Coordination for Entergy Services Inc. in Pine Bluff, Arkansas. There he is responsible for the reliable operation of Entergy’s transmission grid. He has been involved in the North American Synchro-Phasor Initiative since 2006, and is currently responsible for managing Entergy’s Phasor Data Historian and the development and design of applications that use phasor data in real-time operations. He has served as the vice chair and Power Engineering Society chair for the Arkansas section of the IEEE. Vaithianathan "Mani" Venkatasubramanian is a Professor in School of Electrical Engineering and Computer Science, Washington State University, Pullman, WA. He received M.S. and D.Sc. degrees in System Science and Mathematics from Washington University, St.Louis, MO. His research interests include power system stability and control with emphasis on synchrophasor applications. Rubal KC received a BSEE degree from Louisiana Tech.Rubal is an electrical engineer in the Transmission Security Coordination group for Entergy Services Inc. in Pine Bluff, Arkansas... He has been involved in the North American Synchro-Phasor Initiative since 2009, and is currently helps manage Entergy’s Phasor Data Historian and the development and design of applications that use phasor data in real-time operations.
