EAS Lessons Learned Summary Lessons Learned Published in August 2014

RELIABILITY | ACCOUNTABILITY2 Two NERC lessons learned (LL) were published in August 2014 LL Load-Shedding Plans for Localized Events LL Loss of EMS Monitoring and Control Functionality for More Than 30 Minutes August 2014 Lessons Learned

RELIABILITY | ACCOUNTABILITY3 Fire protection system on the 345/115 kV transformer activated isolating the transformer Separation resulted in a loss of voltage support from 345 kV systems to 115 kV systems in the area Reduction in voltage (86%) led to loss of 360 MW coal unit SO placed all Caps in-service and increased reactive on gens Additional gens couldn’t start-up due to low voltage No load-shedding plan to solve a local area voltage issue SOs should have flexible load shedding plans to local area issues SOs should have continual training and guidance on load shedding plans Load-Shedding Plans for Localized Events

RELIABILITY | ACCOUNTABILITY4 Loss of EMS Monitoring and Control Functionality for More Than 30 Minutes System failure triggered by insufficient amount of disc storage space for the Oracle recovery log area  No Oracle services terminated as a result Oracle saves all changes/updates in “redo logs” as backup No storage space in recovery log area led to storage on EMS server Oracle connection was lost and the back-up and alternate EMS servers were notified to failover Failover timed-out on initiating functional primary EMS server Caused server to be brought down (failure-detection strategy)  Other servers not acting as primary since the failover timed-out Set high alarm priority to Relational Database Management System (RDBMS) going online and offline

RELIABILITY | ACCOUNTABILITY5 Links to Lessons Learned Link to Lessons Learned Directions to Lessons Learned: Go to > “Program Areas & Departments” tab > “Reliability Risk Management” (left side menu) > “Event Analysis” (left side menu) > “Lessons Learned” (left side menu) NERC’s goal with publishing lessons learned is to provide industry with technical and understandable information that assists them with maintaining the reliability of the bulk power system. NERC requests that industry provide input on lessons learned by taking the short survey. A link is provided in the PDF version of each Lesson Learned.

RELIABILITY | ACCOUNTABILITY6 For more information please Questions