Grid Operations - Program 39

Grid Operations - Program 39 Program Description Program Overview In many ways, today's power system must be operated to meet objectives for which it was not explicitly designed. Today's transmission system is operated to transfer larger amounts of energy than were considered when it was built, and it is operated much closer to the margin. Generation resources are more constrained and increasingly more variable and uncertain. Demand resources are now a viable option for providing ancillary services in many regions. Under these circumstances, it is imperative that operators be provided with good information based on real-time data regarding the status of the system, as well as decision-making support information to respond to rapid changes in the future. The emergence of new sources of real-time data that are becoming available from synchrophasor measurements and forecasts of coming load and variable renewable output levels enable the possibility of providing operators with increased situational awareness and advanced decision-support tools to reliably and economically operate the system in the face of emerging challenges. EPRI s Grid Operations research program is addressing these needs by improving real-time situational awareness, wide-area protection, reactive power support, and voltage stability margins, as well as the capabilities to manage the grid through extreme events and to restore the system in the event of an outage. Research Value The mission of EPRI's Grid Operations research program is to support the development of next-generation monitoring, analysis, and control capabilities that will be required to operate the transmission grid in the most reliable and economic manner as the generation mix and capabilities change significantly and as load becomes a more prevalent system resource. In 2012, EPRI's Grid Operations research program will offer its members a focused research portfolio with the objectives of: Improving system reliability and reducing operational risks through the improved situational awareness of operators, including the incorporation of equipment health information into the control room and the identification of operating boundaries and margins Supporting operators in ensuring that steady-state and post-contingency system voltage performance is maintained, utilizing the optimal mix of available reactive resources Reducing the risk of wide-area events and improving restoration time in order to reduce outage costs through restoration optimization methods and guided control decision making when separation may be the best choice Developing advanced analysis algorithms that utilize synchrophasor data to support operator situational awareness and decision support Approach EPRI's Grid Operations research program delivers value utilizing the shared experiences and understanding of its utility and independent system operator (ISO) members in conjunction with the expertise of EPRI's staff and network of top-level contractors to conduct research projects that lead to actual methods and tools used by system operators. EPRI also engages with external industry standards, regulatory, and research efforts to ensure that the EPRI research program is taking advantage of the broader industry efforts and advancing the state of the art. Our research program also strives to provide members both short- and long-term value. For example, the 2012 Grid Operations research program will continue the development of innovative methods and software tools for supporting system restoration needs that can occur at any time, while at the same time beginning research to investigate advanced data processing, computing technologies, and solution algorithms to improve the performance of all operational analytics and decision making. p. 1

Accomplishments EPRI's Grid Operations program has provided critically needed technologies and information for its members over many years. Examples include: Generic Operator Training Simulator (OTS), Version 2.0: The EPRI Generic Operator Training Simulator is a PC-based training simulator that allows hands-on training for dispatchers, using a generic 29-station model. The Generic OTS, which can be run on multiple platforms, allows for realistic simulations of many power system phenomena. Users may employ a generic power and light model or incorporate their own models into the OTS. The generic OTS has also been integrated with several Energy Management System (EMS) vendors. Situation Awareness (SA) in Power System Operations: This technical update represents a detailed study of the use of color, automated systems, and predictive SA tools in the power industry. Data were gathered through site visits to three control centers and an online color survey. A total of 27 survey responses from 25 separate EPRI members was collected and analyzed. Prototyping a Decision-Support Tool for the Evaluation of System Restoration Strategy Options: This project studied industry practices and documentation of system restoration plans. A new concept, Generic Restoration Milestone (GRM) during system restoration, was proposed. Based on that, a prototype decision-support tool for evaluating system restoration strategy options was developed. A specific restoration strategy can be established by a combination of GRMs based on system characteristics, energy sources, and constraints of power grids, and then it can be examined through simulations. Different combinations or sequences lead to different strategy options and performances. Simulation studies have shown that the developed decision-support tool enables a power system in a blackout status to restart and self-organize various parts of the system until it achieves complete restoration. Current Year Activities In 2012, EPRI's Grid Operations research program will offer its members a focused research portfolio with the objectives of: Improving system reliability and reducing operational risks through the improved situational awareness of operators, including the incorporation of equipment health information into the control room and the identification of operating boundaries and margins Supporting operators in ensuring that steady-state and post-contingency system voltage performance is maintained, utilizing the optimal mix of available reactive resources Reducing the risk of wide-area events and improving restoration time in order to reduce outage costs through methods and guided control decision making when separation may be the best choice Developing advanced analysis algorithms that utilize synchrophasor data to support operator situational awareness and decision support Estimated 2012 Program Funding $3.0M Program Manager Daniel Brooks, 865-218-8040, dbrooks@epri.com Grid Operations - Program 39 p. 2

Summary of Projects Project Number Project Title Description P39.011 Situational Awareness Using Comprehensive Information P39.012 Online Reactive Power Management and Voltage Control P39.013 Decision Support Tools for System Emergency and Restoration P39.014 New Computing Technologies for Grid Operations P39.015 Synchrophasor Applications This project will help improve system operators' situational awareness. By visualizing comprehensive operating boundary/margin information, operators would be aware of where we are (the operating conditions and status of critical equipment), how far we can go (security margins) and what we should do (decision support for control actions). This goal of this project is to develop advanced study techniques, mitigation measures, and decision-support tools for grid operators and planners to address potential voltage stability problems. This project will investigate critical system operation functions and develop tools to help system operators with decision support in mitigating extreme disturbance events, especially natural disasters, and in restoring power systems. This project will investigate, identify, and develop advanced data processing and computing technologies for control centers to improve online simulation performance in speed, accuracy, and the range of scenarios considered. P39.011 Situational Awareness Using Comprehensive Information (070591) Key Research Question Situational awareness is critical for grid operators to maintain system reliability and minimize major power outages. At present, the rapid growth of regional electricity markets, increasing integration of variable generation resources, and lack of corresponding growth in transmission infrastructure result in more uncertainties in daily grid operations. These changes could result in the transmission system operating even closer to its limit and, thus, increase the likelihood of stability issues during disturbances or equipment failures. The North American Electric Reliability Council (NERC) developed the concept of boundary conditions to point out the importance of real-time operating boundary/margin information for grid operators to be aware of where we are (that is, the operating point), how far we can go (that is, security margins) and what we should do (that is, control actions). In 2011, EPRI started the development of visualizing online operating boundary/margin information and the functional specification for related software development. The developed scheme can interface with existing security assessment techniques to visualize comprehensive operating boundaries and margins in terms of thermal limits, voltage security limits, transient stability limits, and other limits. In addition, the health status of critical power system equipment can help operators recognize potential equipment failures and allow them to take proactive actions, such as unloading a transformer that has shown signs of fatigue. In addition to protecting equipment life, this information allows operators to better assess potential contingencies that might impact reliability. In the past two years, EPRI concentrated functional specification studies on generic equipment classes, identified technology gaps, and developed a roadmap to integrate equipment health information into control centers. This work will continue to integrate and implement equipment health information to improve the system operations awareness of critical components. Grid Operations - Program 39 p. 3

Approach In 2012, the EPRI project team will develop a prototype software application based on the developed functional specification for online visualization of operating boundaries and margins. The application would utilize an operator-friendly graphical user interface (GUI) with concise, easy-to-use displays. Comprehensive boundary/margin information would be visualized about user-definable observation variables, for example, interface power flows, regional loads, and main generator outputs. Its interfaces with online measurements (for example, from SCADA/EMS and synchrophasors) will be developed to estimate the system operating condition. The interfaces with commercialized power system security assessment tools (for example, PSS/E) will also be defined to perform timely updates of operating boundaries and margins under both pre- and post-contingency conditions. For integration of equipment health information, the EPRI project team will develop prototype displays for general classes of equipment based on the functional specifications developed previously. The EPRI project team will work closely with the area experts in equipment diagnosis and communications to address identified technical gaps in the roadmap developed earlier. For example, if there is a certain class of equipment that is deficient in presenting a particular type of health information that the control center would like to have, the EPRI team will work with equipment diagnostics experts to determine a conceptual model for a monitoring device to address the issue. Impact Improve system operators situational awareness by comprehensive operating boundary/margin information. Improve system operators monitoring capabilities on critical equipment and potentially dangerous situations. Possibly reduce the risk of cascading outages caused by insufficient operating margins or equipment failures. How to Apply Results Members can integrate the software application for online visualization of operating boundary/margin information with their SCADA/EMS systems and security assessment programs. The technical results on integration of equipment health information would provide guidelines and techniquesfor monitoring critical equipment in control rooms. EPRI would work with members to apply the results from the project through supplemental projects. 2012 Products Product Title & Description Online visualization tool for comprehensive operating boundary information: This software is to be used for visualizing comprehensive operating boundary and margin information. Integration of Equipment Health into Control Centers: The technical update will address technical gaps in the integration of equipment health information into control centers and provide guidelines on monitoring critical system equipment. Planned Completion Date Product Type 12/31/12 Software 12/31/12 Technical Update P39.012 Online Reactive Power Management and Voltage Control (070592) Key Research Question Voltage stability is a major concern in system operation and a leading factor that limits power transfers. Increasing variable generation and the changing dynamic characteristics of loads bring more challenges to maintain voltage stability in the operating environment. Grid Operations - Program 39 p. 4

Identifying potential voltage instability areas and determining the required reactive power reserve in real time are technical challenges that need to be solved. There are also increasing research needs regarding techniques for optimally managing dynamic VAR reserves to ensure fast voltage recovery, as well as techniques for sensing voltage recovery following disturbances. Current state-of-the-art technologies for voltage stability analysis are based on simulations of what-if scenarios to study potential voltage stability issues. Deploying more synchrophasors opens up the opportunity of using synchrophasor data to perform voltage stability analysis in real time. Combining the measurement-based and simulation-based approaches to help system operators better monitor and control voltage stability is the technical issue to be solved. Approach EPRI has developed advanced study techniques for short-term and long-term voltage stability phenomena. 1) Voltage Control Area (VCA) Technique: EPRI has developed VCA software to investigate steady-state voltage stability performance, identify potential voltage instability areas, and assess optimal reactive power allocation. The 2012 efforts are expected to focus on demonstrating the applicability of the software on a large, realistic power system. 2) Hybrid Online Voltage Stability Monitoring: EPRI has developed a measurement-based voltage stability monitoring (MB-VSM) technique to derive the voltage stability margin at a substation or a defined network interface in real time, based on high-resolution measurement data (for example, from synchrophasors). The 2012 efforts are expected to focus on developing a method for real-time hierarchical voltage stability assessment at substation, load center, and system levels, combining both measurement-based and simulationbased approaches. A graphical user interface will also be developed to facilitate an operator's decision making. 3) Optimal Reactive Power Allocation (ORPA) Method: EPRI has developed this method to investigate shortterm voltage stability phenomena and identify optimal allocation of reactive power resources. The 2012 efforts are expected to focus on demonstrating the applicability of this method on a large, realistic power system. 4) Coordinated Voltage/VAR Control Strategy Utilizing Variable Generation (VG) and Distributed Energy Resources (DER): In addition to conventional voltage support and reactive power resources, dynamic VAR systems operating at the grid interface of wind farms and switching converters inside DER are other devices that can provide reactive power and dynamic voltage control. In 2012, we will investigate how a coordinated control strategy can be developed to optimize the reactive capability of these devices for improved voltage support. Impact Provide guidance on study tools/techniques/procedures/modeling for investigating voltage stability. Identify mitigation measures. Provide situational awareness for potential voltage stability issues. Facilitate decision making to help avoid or mitigate a potential voltage instability scenario. How to Apply Results A member can implement the project results as follows: Use technical reports to enhance voltage stability investigation by improving study procedures, using advanced tools, and developing improved modeling. This will be useful to grid operations staff in real-time contingency analysis and to planning staff in off-line studies. Use VCA software to conduct voltage stability investigations by importing PSS/E or PSLF data to the VCA software. Employ on-line visualization tools in the control center to know the system voltage and reactive reserve status and to facilitate decision-making. Grid Operations - Program 39 p. 5

2012 Products Product Title & Description Reactive Power Management to Address Long-Term Voltage Stability Using Voltage Control Area (VCA) Technique: Members can use Voltage Control Area (VCA) software to conduct voltage stability investigations by importing PSS/E or PSLF data to the software. This will be valuable to grid operators and planners with regard to assessing potential steady-state instability scenarios on their systems. This will facilitate grid operators' decision making to help avoid or mitigate a potential voltage instability problem. Reactive Power Management to Address Short-Term Voltage stability Using Optimal Reactive Power Allocation Method: A member can use the above deliverable to enhance voltage stability investigation by improving study procedures, using advanced tools, and developing improved modeling. This will be useful to the grid operations staff in real-time contingency analysis and to the planning staff in off-line studies. Such studies are expected to help grid operators and planners with regard to potential fast voltage collapse scenarios on their systems and in identifying mitigation measures. Online method for hierarchical voltage stability assessment at substation, load center and system levels: A member can implement the project results by employing on-line visualization tools in the control center to learn the status of potential voltage instability problems. This will be valuable in facilitating an operator s decision making. Planned Completion Date Product Type 12/31/12 Software 12/31/12 Technical Report 12/31/12 Technical Update P39.013 Decision Support Tools for System Emergency and Restoration (070593) Key Research Question System restoration is important operation function to minimize the impacts of major disturbance events. The occurrence of natural disasters is one example. The impact of such events on electric power system functioning has been of interest to countries worldwide. Effective system control and restoration can promptly bring a system in blackout or separation status back to service. However, for system restoration, operators need online tools to evaluate restoration strategy options and efficiently determine restorative actions without causing security violations. Special considerations need to be taken in such emergencies. System operators need special control plans and strategies in preparation against natural disasters. Approach In 2009-2011, EPRI prototyped a decision-support tool for evaluating restoration strategy options. Based on the developed techniques, this project will develop, enhance, and demonstrate software applications for intelligent system restoration. The decision-support tool for system restoration will be further enhanced to integrate into operator training simulators (OTS) and later with EMS. In addition, the team will look at specific disasters worldwide and assess critical functions of control centers under emergency conditions. Critical functions may include, but are not limited to, (a) dispatch and grid operations, (b) system restoration plans and protocols, and (c) communication (data management and analysis, and data/information transmittal to control centers). Impact May assist in developing precautionary emergency control plans and strategies against natural disasters. May shorten system restoration time to reduce loss. Improve system operators confidence when making decisions. Grid Operations - Program 39 p. 6

How to Apply Results Findings and functions developed for control centers under emergency conditions may be used in emergency control centers to curtail the impact of disasters on the power system and to carry out recovery actions in order to minimize social disruption. System operation staff may use the system restoration decision-support tool in training to improve their knowledge of effective restoration strategies. EPRI may offer training courses and supplemental project opportunities to help members apply the tools. 2012 Products Product Title & Description Functional Specification for System Emergency Grid Operation Tools in Natural Disasters: Develop functional specifications for control centers under emergency conditions to curtail the impact of disasters on the power system and to carry out recovery actions in order to minimize social disruption. Decision support tool for system restoration: This decision-support tool is designed for system restoration engineers to develop and evaluate restoration strategies, which will reduce restoration times and facilitate better communication of restoration steps across all stakeholders. Planned Completion Date 12/31/12 Product Type Technical Update 12/31/12 Software P39.014 New Computing Technologies for Grid Operations (070594) Key Research Question To manage the added complexity in the power system, the operator s job can be facilitated by deploying advanced computing technologies, which can include new simulation techniques, software, and hardware, that can potentially accelerate data analysis and computer simulation tasks. There are a number of ways to improve simulation performance that can be explored: Improved information Utilities are installing more and more sensor technologies, such as synchrophasors and line sensors, so that faster, more intelligent data processing is needed to quickly filter raw data into concise information. New modeling structures Various model structures can allow for faster and/or more accurate mathematical operations. Advanced mathematical solvers New, advanced computational mathematic techniques can improve simulation speed and accuracy. Advanced software and hardware technologies Technologies such as, but not limited to, reduced instruction set computer (RISC), graphic processor unit (GPU), multi-core, distributed computing, and virtualization may improve simulation speeds or investment costs and utilization. There are many technologies to consider, and there are technologies that can complement each other. This project will focus on identifying the near-term application enhancements that can utilize the most complementary methods listed above to improve simulation performance in speed, accuracy, and the range of scenarios considered for system operations. Approach The 2011 project results will highlight the best near-term technologies and methods for improving online simulation and analysis tasks and set the guidelines for a few specific applications that are mature enough for near-term implementation. The 2012 scope will continue to monitor the developments in the investigated computational technologies and begin to integrate the guidelines set forth in the 2011 results. The main objectives of the 2012 work will be further development of functional specifications for integrating the key applications identified in 2011 through detailed description of the algorithm and modeling structure to begin to Grid Operations - Program 39 p. 7

address practical issues, an offline case study to demonstrate the feasibility of selected applications, and an investigation of the impacts of the targeted applications' modification on other applications. Impact May reduce the risk of cascading outages by improving online simulation and analysis techniques. May provide an advanced computing foundation for the new smart grid environment in which a greater abundance of online data exists. Improve the utilization of existing or introduce new low-cost computing technologies into control centers. How to Apply Results Implementation guidelines for integration and case study results will be documented in a report. EPRI may provide application services to help members apply these technologies. 2012 Products Product Title & Description Implementation Plan for Advanced Data Processing, Mathematical Techniques and Computing Technologies to Enhance Simulation Tasks: This technical update provides a detailed implementation plan for integrating complementary advanced data processing, mathematical techniques, and computing technologies to enhance the simulation performance of a targeted application. Planned Completion Date 12/31/12 Product Type Technical Update P39.015 Synchrophasor Applications (072024) Key Research Question Synchrophasors are precise grid measurements that are now available from monitors called phasor measurement units (PMUs). Because they have the capability of directly measuring phase angles at high sampling rates and accuracies, synchrophasors are prompting a revolution in power system operations as next generation measuring devices. As with the smart grid investment grants and demonstration projects funded, an additional 850 PMUs are going to be installed, which will bring the United States total to over 1,000 in the next three years. The objective of this project is to accelerate the development and adoption of PMU analytics. In 2012, this project will focus on the following two analytics: 1. Real-time event processing and analysis tool 2. Comprehensive nline stability analysis Approach This project will first review the present techniques related to real-time event processing and synchrophasorbased stability analysis. The project will then incorporate the following two aspects: Real-time event processing and analysis tool: Propose an integrated environment for analyzing synchrophasor data event detection and location algorithms identified as most useful (the 2010 project Synchrophasor Success Stories will provide the basis for the research); develop a critical event recognition algorithm that has intelligent learning capability; and write up the overall functional requirements for an integrated event-analysis tool. Grid Operations - Program 39 p. 8

Comprehensive online stability analysis: Investigate trajectory analysis on synchrophasor measurements for stability analysis. This investigation may integrate analytical tools for both small-signal stability (for example, modal analysis) and large-signal stability (for example, the energy function) to provide an early warning of potential instability under a long sequence of disturbances. Based on those investigations, develop a methodology for optimizing the design or configuration of a synchrophasor network for online stability analysis. Impact Improve system operators' situational awareness and reliability through real-time recognition of events as they happen. Improve system operators capability to monitor and control the stability of the transmission system. How to Apply Results Members will be trained through webcasts and workshops on the concepts and methodologies of this project. New tools developed in this project will be provided to members for testing on their systems, and the results will be shared among members to enhance the experience and apply the technical results of this project. 2012 Products Product Title & Description Comprehensive Stability Analysis Using Synchrophasors: This technical update will document new methodologies and study results. Functional Requirements for Real-Time Event Analysis Tool: This technical update will provide the functional requirements for the next generation real-time event-analysis tool. Planned Completion Date 12/31/12 12/31/12 Product Type Technical Update Technical Update Grid Operations - Program 39 p. 9

Supplemental Projects Guidelines for Implementing Dynamic Thermal Circuit Rating (DTCR) in Systems and Market Operation (072025) Background, Objectives, and New Learnings Experience with a number of utilities indicates that the ratings of power equipment via dynamic thermal circuit rating (DTCR) are typically 5% 15% higher than conventional static ratings. EPRI Programs 35 (Overhead Transmission) and 37 (Substations) are investigating the ability to forecast DTCR one day ahead, based on weather forecasts. Can the combination of these new capabilities increase system benefits and minimize operational risks Application of dynamic ratings may enhance economical operation by enabling less-constrained operation and timely mitigation action that avoids dangerous system security conditions by tracking the thermal state of equipment. Significant economic benefits from increased use of DTCR are also possible through the use of forecasting. To make efficient use of such forecasts, system and market operators need to know how much to safely relax thermal ratings to achieve economic benefits without increasing operational risk. Project Approach and Summary EPRI proposes to perform various demonstration studies of control areas, investigating how dynamic line rating can be integrated into system and market processes including how prices and energy dispatch may change thoughout the network. A second focus will be to determine the changes in requirements for reserves and their allocations. These investigations may include: Methods to quantify economic benefits without increasing operational risks Impact of dynamic line rating on contingency analysis Options that the system operator has to react to real-time DTCR changes Relationship between increased line ratings and path throughput Economic benefits from relaxed line ratings Accuracy requirements for DTCR forecasts to meet operational and market needs Benefits Successful completion of this project could: Help operators take advantage of increased power equipment utilization. Increase transmission capability and bring economic benefits to consumers. Improve operators ability to respond to real-time DTCR changes. Improve system reliability. Help system operators avoid false congestion and security alarms by providing sound operating limits through real-time ratings of system equipment. Provide sound engineering judgments in applying dynamic ratings to operational decision making. Grid Operations - Program 39 p. 10

Feasibility Assessment for Implementing Advanced Voltage Control (072026) Background, Objectives, and New Learnings Voltage profile and stability are important concerns in planning and operating electric power systems with increased power flow. One of the important operating tasks of power utilities is to keep voltage within an allowable range for high-quality customer services. Electric power loads vary from hour to hour, and voltage can be varied by the change of the power load. Power utility operators use a variety of equipment, such as generators, transformers, static condensers (SC), and shunt reactors (ShR), to control voltage. Traditionally, voltage is controlled in a decentralized way at the power plant or substation level. Hence it lacks wide-area coordination and optimization among local voltage controllers, such as automatic voltage regulators in power plants. Voltage violations and unexpected massive reactive power transfers occur sometimes. In recent years, system-wide hierarchical dynamic voltage control (HDVC) has been investigated, developed, and implemented in some systems. While power systems are experiencing ever-increasing varying loading conditions, the sophisticated HDVC process can effectively maintain a steady voltage within preset limits. HDVC systems have the potential to reduce transmission system loss, increase system MVAR reserve, and improve system reliability for pre-contingency and post-contingency. To better understand HDVC technology and implement the technology into the power system, EPRI is working with pioneering researchers and investigators to evaluate the feasibility for implementing HDVC technology. This group is also investigating possible practical considerations and issues to deploy the technology in actual systems. The deployment of HDVC systems is expected to achieve better voltage performance and improve reliability, quality and economy in system operation. Project Approach and Summary EPRI will work closely with each project member to identify specific details and issues for a successful implementation. This will be done with conference calls, webcasts, and presentations of system conditions and optional implementation schemes. This methodology is intended to help participants understand their needs for a future implementation. The reporting of case studies and analysis helps utilities and system operators plan their own detailed implementation. Benefits This study assists system engineers in understanding the outcome of hierarchical dynamic voltage control system deployment in: Controlling system voltage profile Reducing transmission system loss Increasing system MVAR reserve Improving system reliability for pre- and post-contingency Grid Operations - Program 39 p. 11

Early Warning of Potential Wide-Area Stability Problems Using Synchrophasors (072027) Background, Objectives, and New Learnings Large power system blackouts, although infrequent, may influence up to tens of millions of people and result in huge costs. Usually, a major power outage is not caused by a single fault; rather, it is more likely to be the result of a sequence of disturbances, including initial events, additional failures, consequent protective actions, increasingly vulnerable conditions, and accelerated cascading outages, leading to a loss of stability. Those disturbances may gradually weaken a power system s connections and result in growing inter-area angular oscillations. If not damped, oscillations may evolve into a loss of synchronism between two or more groups of generators and even system islanding. Increasing deployment of synchrophasors, for example, phasor measurement units (PMUs), on transmission systems can provide opportunities for monitoring of real-time wide-area power system dynamics. However, available applications of synchrophasors are mainly in displaying and visualizing their measurements. Grid operators need advanced applications that are able to turn raw measurements into more meaningful knowledge, such as online security margins, risks of stability problems, and indication of potential cascading outages. Since 2008, EPRI has conducted research and development on the application of synchrophasors in the early warning of potential wide-area stability problems involving increasing oscillations and loss of synchronism between interconnected regions. EPRI filed a U.S. patent application in 2010 on a synchrophasor-based algorithm for predicting the loss of synchronism in interconnected power systems. Project Approach and Summary Based on EPRI s accomplishments in synchrophasor applications, this project will develop a software engine for the early warning of potential wide-area stability problems using synchrophasor data. If fed with a time series of synchrophasor data at dispersed locations, the software engine would offer the following functions: For user-definable regions (that is, groups of synchrophasors) in a power system, dynamically identify dominant inter-area oscillations between those regions and the related mode shapes. Among those regions, dynamically identify the most dangerous interfaces of angle separation. Conduct a stability assessment on the dynamically identified interfaces to estimate the angular stability margin. Provide a real-time warning on the potential loss of synchronism if the stability margin on any interface is found below the expected level. The outputs of the software engine include modal information on dominant inter-area oscillations and the estimated values of stability margin indices. The project will define the software s data interfaces to phasor data and visualization tools so that the participants of the project can easily test the software engine on their grids and integrate it into their real-time monitoring systems. Benefits Provide wide-area angular stability monitoring using synchrophasors. Provide real-time trends on the angular stability margin during a sequence of disturbances. Indicate the critical grid interfaces where stability problems may potentially happen and proactive control actions should be added. Possibly reduce the risk of cascading outages by providing early warning of insufficient stability margin so that a grid operator can employ pre-defined operating procedures on a timely basis. Grid Operations - Program 39 p. 12