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Summary of ISO New England DCS Event A nalysis for September 2, 2010. September 2, 2010 Background. New England was experiencing a late season heat wave September 2 nd peak load of 26,098 MW was an all-time September peak
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Summary of ISO New England DCS Event Analysis for September 2, 2010
September 2, 2010 Background • New England was experiencing a late season heat wave • September 2nd peak load of 26,098 MW was an all-time September peak • System reserve monitor indicated surplus in both 10 and 30 minute operating reserves • Following a large source contingency on-line and off-line resources under performed during the recovery of the Area Control Error (ACE) • Failed to recover from the source loss within the NERC Reliability Standard requirement of 15 minutes
NERC Reliability Standard Requirement • Standard BAL-002 - Disturbance Control Performance • R4. A Balancing Authority or Reserve Sharing Group shall meet the Disturbance Recovery Criterion within the Disturbance Recovery Period for 100% of Reportable Disturbances. The Disturbance Recovery Criterion is: • R4.1. A Balancing Authority shall return its ACE to zero if its ACE just prior to the Reportable Disturbance was positive or equal to zero. For negative initial ACE values just prior to the Disturbance, the Balancing Authority shall return ACE to its pre-Disturbance value. • R4.2. The default Disturbance Recovery Period is 15 minutes after the start of a Reportable Disturbance. This period may be adjusted to better suit the needs of an Interconnection based on analysis approved by the NERC Operating Committee. • Reportable Disturbance is defined as any contingency ≥ 80% of the First Contingency Loss
Event Overview • At 13:09 New England experienced a large source contingency of approximately 1400 MW • NPCC Shared Activation of Reserve was limited due to heavy imports from New York • Operating Reserves dispersed across many units due to the size of the first source contingency and the operating response rates of available resources • Recovery of ACE to pre-contingent value took approximately 23 minutes
Recovery Actions • Desired Dispatch Points (DDPs) were sent to 147 generators via Electronic Dispatch to increase output for a total of 1941 MW • 56 start ups for a total of 935 MW • 91 online units for a total of 1006MW • At ~13:23, an economic (non-emergency) DDPs were sent due to response to the Contingency Dispatch not being sufficient to recover the ACE within 15 minutes • ACE was restored to its pre-contingent value at ~13:33
Actual ACE vs. modeled ACE recovery if all resources responded according to response rate
ISO New England’s Internal Analysis • Evaluated operator tools and surveyed Designated Entities to gain a better understanding of NERC violation • Actions taken: • Improvements to procedures or standards for: • Generator displays and alarms • Acknowledgement and compliance of DDPs sent to generators • Testing and verification of the functionality of communication equipment for receiving and responding to DDPs • Evaluation of generator performance audits • Generator operator training • Improvements to ISO systems related to: • Ability to monitor DDP receipt & acknowledgement by generators
ISO New England’s continuing efforts • Monitor generator performance following every emergency dispatch • Operations provides feedback to generators that seem deficient • Face-to-face meeting with generators to discuss and understand performance • Better real time performance monitoring • Working to improve comprehensive generator auditing program