Misoperations Report - NERC

1 NERC | Protection System Misoperation Task Force Report | April, 2013 1 of 40 Misoperations Report Prepared by: Protection System Misoperations Task Force Approved by NERC Planning Committee on April 8, 2013 April 1, 2013 3353 Peachtree Road NE Suite 600, North Tower Atlanta, GA 30326 404-446-2560 | NERC | Protection System Misoperation Task Force Report | April 2013 2 of 40 Table of Contents Table of Contents .. 2 Executive Summary .. 3 Introduction .. 5 General Observations and Conclusions .. 8 Overview of Historic Misoperations .. 8 Historical SERC Protection System Misoperations Review .. 8 Historical NPCC Protection System Misoperations Review .. 9 Historical TRE Protection System Misoperations Review.

2 11 Historical MRO Protection System Misoperations Review .. 12 Historical RFC Protection System Misoperations Review .. 14 Historical SPP Protection System Misoperations Review .. 16 Historical WECC Protection System Misoperations Review .. 17 Historical FRCC Protection System Misoperations Review .. 19 Misoperations Analysis and Observations .. 21 Summary of Misoperations NERC-Wide from January 1, 2011 to March 31, 2012 .. 21 Sub-Group Analyses and Observations .. 25 Relay Settings/Logic/Design Errors Sub-Group Analysis .. 25 Relay Failures Sub-Group Analysis .. 28 Communication Failures Sub-Group Analysis .. 31 Suggestions for Improvement and Other Observations .. 35 Suggestions to Reduce Misoperations .. 35 Suggestions to Improve Data and Analysis.

3 36 NERC | Protection System Misoperation Task Force Report | April 2013 3 of 40 Executive Summary The Protection System Misoperations Task Force (PSMTF) was formed to analyze one of NERC s top priority reliability issues protection system Misoperations . PSMTF analyzed protection system misoperation data, researched possible root causes, and developed observations, conclusions and recommendations which can help Registered Entities manage risk by reducing the most frequent causes of protection system Misoperations . The misoperation data collected since January 1, 2011 from the NERC Protection System Misoperation Reporting Template would be analyzed. Since 2011, each Regional Entity has collected misoperation data with uniform guidelines in a consistent format.

4 This data provides over 1,500 Misoperations across all eight Regions and provides fifteen months of data for analysis. Additionally, a summary of each Region s misoperation process and observations/conclusions from data collected prior to January 1, 2011 are included. Approximately 65% of Misoperations are grouped under three cause codes: Incorrect settings/logic/design errors, relay failures/malfunctions, and communication failures. To maximize the task force s effort, the PSMTF focused on these three cause codes in depth, and the cause codes resulting in fewer Misoperations were not studied. These areas will be analyzed if they emerge as one of the primary causes in the future. This decision was also supported by the results of the Regions historic look-back ( Misoperations collected prior to January 1, 2011) which also identified these three cause codes as being the prevalent causes of Misoperations .

5 After analyzing the misoperation data, the PSMTF found ways to potentially reduce the amount of future Misoperations . These results are summarized in Figure ES-1. Since some entities already perform one or more of these activities, entities should consider these suggestions for improvement based on their particular circumstances. Figure ES-1: Suggestions for Improvement In addition to the suggestions for improvement above that may have a short-term impact on reducing Misoperations , the PSMTF also proposes several suggested improvements to the data collection process that may improve the usefulness of future data collection, which in turn may drive further improvements in the long-term.

6 First, all three analysis sub-teams Applications requiring coordination of functionally different relay elements should be avoided. If these applications cannot be avoided, the coordination should be studied and tested thoroughly. This type of coordination is virtually always problematic, and is the cause of numerous Misoperations reported in the study period. Some examples to avoid include: Mixture, in the same scheme, of distance elements and overcurrent elements Distance and directional overcurrent elements at opposite line terminals that use different directional polarization methods, particularly in the same pilot scheme Overcurrent elements that use different measurement methods, such as phase vs. residual ground vs.

7 Negative-sequence current measurement Proper Application of Relay Elements Misoperations due to setting errors can potentially be reduced. Techniques that could be used to reduce the application of incorrect settings include: Peer reviews Increased training More extensive fault studies Standard templates for setting standard schemes using complex relays Periodic review of existing settings when there is a change in system topography Settings Errors Entities should evaluate the need to apply updated firmware. While many firmware updates may not be critical to the relay protection functions, updated firmware that corrects critical protection functions should be given priority. Microprocessor-based Relay Firmware Executive Summary NERC | Protection System Misoperation Task Force Report | April, 2013 4 of 40 observed a large number of records (over 24%) that were either categorized incorrectly or had insufficient information to support the category assigned.

8 Template enhancements and additional guidance on what to Report should be provided to misoperation reporters. Presently, there is opportunity for over-counting Misoperations due to a lack of unique identifiers for BES elements (BES elements are entered in free text format) or due to the same cause within a time span where it would be impractical for an owner to respond. Similarly, reporting entities should coordinate with adjacent companies when reporting Misoperations of tie lines to avoid double reporting. The addition of subcause codes to the misoperation template should be investigated by the SPCS. In the future, the NERC PSMTF and NERC SPCS (System Protection Control Subcommittee) recommend that misoperation analysis be continued, on an annual basis, by the respective protection system subcommittees within each Regional Entity.

9 This analysis shall be forwarded to the NERC SPCS and NERC PAS for trending and metrics reporting. Lastly, while not a direct result of analyzing this data, the PSMTF observes that it is not possible to eliminate all Misoperations . It is important therefore, that entities utilize a collaborative effort among protection engineers, transmission planners, and other engineers ( design and communication engineers) to work together to determine proper protection system scheme application and setup to ensure proper emphasis on dependability and security. The intent of this cooperative work is to mitigate the system impact of Misoperations , not to necessarily reduce the number of Misoperations .

10 NERC | Protection System Misoperation Task Force Report | April 2013 5 of 40 Introduction Purpose The Protection System Misoperations Task Force (PSMTF) was formed to analyze one of NERC s top priority reliability issues protection system Misoperations . The PSMTF was approved by the NERC Planning Committee in March, 2012. The task force was formed and started work in April, 2012. The majority of the group consists of protection system technical experts from across the eight Regions. PSMTF analyzed protection system misoperation data, researched possible root causes, and developed observations, conclusions and recommendations which can help Registered Entities manage risk by reducing the most frequent causes of protection system Misoperations .