ERCOT Planning Horizon SOL Methodology Update Jeff Billo RPG December 7, 2012 Background • Per FAC-010-2.1 the Planning Authority (ERCOT) is to establish a documented SOL.
Download ReportTranscript ERCOT Planning Horizon SOL Methodology Update Jeff Billo RPG December 7, 2012 Background • Per FAC-010-2.1 the Planning Authority (ERCOT) is to establish a documented SOL.
ERCOT Planning Horizon SOL Methodology Update Jeff Billo RPG December 7, 2012 Background • Per FAC-010-2.1 the Planning Authority (ERCOT) is to establish a documented SOL methodology for its area – ERCOT has issued a change to the methodology and communicated that change per Requirement 4 • Why are we making these changes? – Better align planning horizon SOL/ IROL methodology with TPL003 and PRC-023 – Learn from Southwest Event • What changes are we making? – General rewrite – Add SOL/ IROL identification for steady-state cascade conditions – Better define IROL identification – Effective January 1, 2013 December 7, 2012 2 RPG How does PRC-023 fit in? • Defines transmission circuit relay loadability requirements for Transmission Owners • Provides 13 different methods for TOs to set their phase protective relay settings – Based on this we have used the conservative assumption that transmission circuits loaded above 150% of their normal rating or 115% of their emergency (2-hour) rating will trip – Assumption used for screening purposes only • Limitation – Applies only to facilities 200 kV or higher or 100-200 kV facilities that the Planning Coordinator identifies as ‘critical to the reliability of the BES’ December 7, 2012 3 RPG PRC-023 Side Note • Assume all 345 kV facilities set per PRC-023 • Run separate analysis to identify 138 kV circuits that will lead to Cascade event if relays are set between 100% loading and PRC-023 loadability requirements – Report 138 kV circuits as ‘critical to reliability’ if meet this criterion December 7, 2012 4 RPG How is ERCOT applying this? • In ERCOT’s TPL standard analysis, no facilities should be loaded above 100% for Category A or B contingencies • If the analysis shows that for a Category C (multi-element) contingency facilities will be loaded above 150% of the normal rating or 115% of the emergency rating then we will assume that the facility will trip – If this causes a Cascade condition then ERCOT Planning will investigate and take one or more of the following actions if the Cascade condition is confirmed (per Category C Planning process): • Plan an upgrade • Plan a Mitigation Plan (including RAPs and/or load shed) December 7, 2012 5 RPG How is ERCOT applying this? • An SOL will be created when … 1. Manual system adjustment (switching, load shed, etc.) is required in order to prevent cascading or voltage collapse; 2. A stability limit is identified; 3. Voltage stability margin is less than 5% for NERC Category B contingencies or 2.5% for Category C contingencies; or 4. Post disturbance frequency is not within 59.4 Hz to 60.4 Hz • The SOL will be classified as an IROL if the load loss (either via manual load shed or as a consequence of the event) is greater than four times 1% of the load in the case • The IROL Tv will be defined as the lower of the relay trip setting time delay or 30 minutes December 7, 2012 6 RPG Comments or Questions? Send formal comments to: [email protected] December March 12, 7, 2010 2012 7 RPG Appendix December March 12, 7, 2010 2012 8 RPG Quick Example on Facility Ratings (courtesy of WECC) Load Shed (15 min) Limit Exceedance = Go beyond limit Emergency (2 hour) Limit Violation = Exceed limit for a time duration longer than required mitigation time Normal (continuous) 0 MVA December 7, 2012 9 RPG Quick Example on Facility Ratings Load Shed (15 min) Emergency (2 hour) Normal (continuous) Operate in this range all you want. Nothing is being exceeded, nothing is being violated. 0 MVA December 7, 2012 10 RPG Quick Example on Facility Ratings Load Shed (15 min) Operate in this range for no more than 2 hours: Emergency (2 hour) Normal (continuous) 1. 2. You are exceeding the normal rating. You are violating the limit if you operate in this range for longer than 2 hours. 0 MVA December 7, 2012 11 RPG Quick Example on Facility Ratings Load Shed (15 min) Operate in this range for no more than 15 minutes: Emergency (2 hour) 1. Normal (continuous) 2. You are exceeding the emergency rating. You are violating the limit if you operate in this range for longer than 15 minutes. 0 MVA December 7, 2012 12 RPG Quick Example on Facility Ratings You can’t operate over this limit. If you do you may damage equipment, cause safety problems and/or trip the facility Load Shed (15 min) Emergency (2 hour) 1. Normal (continuous) 2. You are exceeding the load shed rating. To exceed the highest time-limit rating established is to violate the limit. 0 MVA December 7, 2012 13 RPG Quick Example on Facility Ratings Normal (continuous) = Emergency (2 hour) = Load Shed (15 min) If all ratings are the same, you can never operate over the normal limit. If you do you may damage equipment, cause safety problems and/or trip the facility 1. 0 MVA 2. December 7, 2012 14 You are exceeding the load shed rating. To exceed the highest time-limit rating established is to violate the limit. RPG