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CSWG/RCWG05/11/2012
Price Validation and Correction
Resmi SurendranManager, Market Analysis
2
Protocol - When Prices Are Final
May 11, 2012 ERCOT CSWG/RCWG Meeting
4.5.3(4) All DAM LMPs, MCPCs, and Settlement Point Prices are final at 1000 of the next Business Day after the Operating Day. After DAM LMPs, MCPCs, and Settlement Point Prices are final, if ERCOT determines that prices are in need of correction, it shall notify Market Participants and describe the need for such correction. DAM LMPs, MCPCs, and Settlement Point Prices cannot be changed unless the ERCOT Board finds that the DAM LMPs, MCPCs, or Settlement Point Prices are significantly affected by a software or data error.
6.3(4) All Real-Time LMPs, SASM MCPCs, and Real-Time Settlement Point Prices are final at 1600 of the next Business Day after the Operating Day. After Real-Time LMPs, SASM MCPCs, and Real-Time Settlement Point Prices are final, if ERCOT determines that prices are in need of correction, it shall notify Market Participants and describe the need for such correction. Real-Time LMPs, SASM MCPCs, and Real-Time Settlement Point Prices cannot be changed unless the ERCOT Board finds that the Real-Time LMPs, SASM MCPCs, or Real-Time Settlement Point Prices are significantly affected by a software or data error.
3
Protocol – How Prices are Corrected
6.3 (3)(a) If it is determined that the Real-Time Settlement Point Prices are erroneous and correcting such prices will not affect the Base Points that were received by Qualified Scheduling Entities (QSEs), then ERCOT shall correct the prices before the prices are considered final in paragraph (4) below.
6.3 (3)(b) If it is determined that correcting the Real-Time Settlement Point Prices will affect the Base Points that were received by QSEs, then ERCOT shall correct the prices before the prices are considered final in paragraph (4) below and settle the Security-Constrained Economic Dispatch (SCED) executions as failed in accordance with Section 6.5.9.2, Failure of the SCED Process. 6.3 (3)(c) If the Base Points received by QSEs are inconsistent with the Real-Time Settlement Point Prices, then ERCOT shall consider those Base Points as due to manual override from the ERCOT Operator and settle the relevant Settlement Interval(s) in accordance with Section 6.6.9, Emergency Operations Settlement.
6.5.9.2 (2) For intervals that the SCED process fails to reach a solution, then the LMPs for the interval for which no solution was reached are equal to the LMPs in the most recently solved interval. For Settlement Intervals that the Real-Time Settlement Point Prices are identified as erroneous and ERCOT sets the SCED intervals as failed in accordance with paragraph (3)(b) of Section 6.3, Adjustment Period and Real-Time Operations Timeline, then the LMPs for the failed SCED intervals are equal to the LMPs in the most recently solved SCED interval that is not set as failed. ERCOT shall notify the market of the failure by posting on the MIS Public Area.
ERCOT Board MeetingApr 19, 2011
4
Price Correction Schemes and Timelines among ISOs
May 11, 2012
Comparison of Pricing Schemes among ISOs
NY ISO Mid West ISO
ERCOT ISO New England
PJM CAISO
Ex-ante Ex-post Ex-ante Ex-post Ex-post Ex-ante
Timeline for Price Corrections
NY ISO Mid West ISO
ERCOT ISO New England
PJM CAISO
One (1) day to reserve prices.
Three (3) calendar days for investigation and correction.
Five (5) business days.
One (1) business day.
Five (5) business days for RT; Three (3) business days for DA.
One (1) business day for normal verification.
Two (2) business days for notification.
Ten (10) calendar days for corrections.
Five (5) calendar days for validation and correction.
Source: http://www.caiso.com/Documents/Agenda_Presentation-MarketPerformance_PlanningForumJan26_2012.pdf
ERCOT CSWG/RCWG Meeting
5
Reasons for Price Corrections
NY ISO
PJM ISO NE CAISO ERCOT
Hardware Outage √ √ √
Software Failure/ Instability/ Upgrade/ Migration
√ √ √ √ √
Software Error/Limitation √ √ √ √
Operator Input Error √ √ √ √
Data Error √ √ √ √ √
Telemetry Error √ √ √ √
Posting Error √ √
Source: http://www.caiso.com/Documents/Agenda_Presentation-MarketPerformance_PlanningForumJan26_2012.pdf
May 11, 2012 ERCOT CSWG/RCWG Meeting
6
Methods to Correct Prices
NY ISO Mid West ISO
ERCOT ISO New England
PJM CAISO
Replace with adjacent intervals;
Replace with advisory intervals;
Substitute with similar node price;
Replace with other markets.
Replace adjacent interval if it is less than 12 intervals;
Replace the full hour if all intervals of the hour are affected.
Recalculate prices;
Replace with last successful interval;
Substitute with similar node price;
Recalculate prices to reasonably reflect the expected results without error.
Recalculate prices;
Replace with last successful interval if less than 6 intervals are affected;
Replace the hour if more than 6 intervals are affected.
Replace with adjacent interval;
Rerun market;
Selective recalculation;
Replace with other market prices.
Source: http://www.caiso.com/Documents/Agenda_Presentation-MarketPerformance_PlanningForumJan26_2012.pdf
May 11, 2012 ERCOT CSWG/RCWG Meeting
7
ERCOT Historic Price Corrections
Before prices became final
Taken to Board for approval
DAM 23(Totally 8,020 SPPs
corrected)
1(Totally 4,579 SPPs corrected)
RTM 39(Totally 36,701 SPPs
corrected)
2(Totally 734 SPPs corrected)
SASM 0 0
May 11, 2012 ERCOT CSWG/RCWG Meeting
8
ERCOT Price Validation Tool (PVT)
Price Validation is done for: DAM
Immediately after each DAM execution. For each hour of the next Operating Day.
SCED Automatically executed at real time. For each SCED Interval and each Settlement
Interval.
SASM Automatically executed after each SASM run. For each hour in the SASM.
May 11, 2012 ERCOT CSWG/RCWG Meeting
9
Core Price Validation Tests
May 11, 2012 ERCOT CSWG/RCWG Meeting
10
Core Price Validation Tests
May 11, 2012 ERCOT CSWG/RCWG Meeting
11
Core Price Validation Tests (cont’d)
May 11, 2012 ERCOT CSWG/RCWG Meeting
12
Core Price Validation Tests (cont’d)
May 11, 2012 ERCOT CSWG/RCWG Meeting
13
Price Validation Statistics
Market Type
# of intervals # of price checks Types# of validation
checks
DAM 24 hours544 Settlement Points3,700+ CRR Options42,000+ PTP OBL
Error 68
Warning 8
Informative 11
SCED
96 Settlement Intervals
544 Settlement Points469 Meter Prices
Error 31
Warning 18
Informative 9
288+ SCED Intervals
10,189 Electrical Buses449 Resources
Error 10
Warning 5
Informative 1
SASM case by case case by case Error 28
Note: the above statistics are based on OD 5/8/12 snapshot.
May 11, 2012 ERCOT CSWG/RCWG Meeting
14
• Price Validation Team performs the following daily checks to identify potential pricing issues:– Error/Warning flags from automated daily Price Validation
Reports– CRR/PTP Payout spike(s)– Price trends, congestion pattern and market convergence– Outages on heuristic table mapping
• If a potential pricing issue identified:– Upper management is notified– A price investigation market notice is sent out through – Price investigation is immediately conducted– A price correction may be proposed by the team
• If a price correction is approved internally by ERCOT managers:– A price correction market notice is sent out through – Price correction data is prepared and posted by deadline– Price corrections that past deadline are brought to Board
Price Validation/Correction Process
May 11, 2012 ERCOT CSWG/RCWG Meeting
15
Types of Errors for Previous Price Corrections
Scenario Data Issues/Examples
Planned Site failover Maintenance
EMS Load Forecast application failed during planned Network Model Database Load. SCED Solutions of few subsequent intervals not sent to MPs (2/8/11)
Planned Site Failover and Software Upgrade. 15 SCED Intervals failed during site failover execution. EBNRT data missing, stale EMS data, solutions of few subsequent intervals not sent to MPs (4/5/11)
Planned Site Failover. 2 SCED intervals failed and solutions of few subsequent intervals not sent to MPs (6/7/11, 11/29/11)
Planned Site Failover. 1 SCED interval failed and solutions of few subsequent intervals not sent to MPs (10/4/11)
Planned Site Failover Maintenance for Software Migration. SCED was down for 55min (5/22/11)
Planned Site Failover Maintenance for Software Migration. 11 SCED intervals were lost. EBP offset deployed (7/24/11)
May 11, 2012 ERCOT CSWG/RCWG Meeting
16
Types of Errors for Previous Price Corrections
Scenario Data Issues/Examples
Hardware failure
Node Eviction on EMS Database. Stale EMS data (5/10/11)
Loss of Heartbeat on MMS Application Server. SCED intervals were lost and the solutions of few subsequent intervals not sent to MPs (7/21/11)
Loss of Heartbeat on MMS Application Server. SCED intervals were lost, EBP offset deployed (7/23/11)
Due to System issues (High RAC Interconnect Traffic & VIO Servers CPU high Utilization), SCED intervals got affected because failure of save case creation caused EMS Data Transfer to SCED to be delayed (8/13/11)
Communication failure caused by following an incorrect process while decommissioning a DNS server. 8 SCED Intervals failed. (2/2/12)
Unstable/crashed database
EBNRT missing – Unable to locate issue. (3/13/11)
May 11, 2012 ERCOT CSWG/RCWG Meeting
17
Types of Errors for Previous Price Corrections
Scenario Data Issues/Examples
Application failure
ETA application failure during planned Network Model load process. EB SF missing (12/15/10)
QSE ICCP process stalled on both TCC and ACC sites. Suspicious telemetry data (4/1/11)
RTCAM savecase issue. Constraint missing (5/25/11)
EMS Applications failed to automatically restart following local failover during database load process (10/26/11)
EMS STLF application did not calculate the short-term load forecast for 50 minutes. GTBD data error (11/6/11, 11/7/11)
ETA application failure during planned Network Model load process (4/11/12)
RLC Application had issue reading updated SCED base points. SCED solution was unavailable to EMS (4/26/12)
May 11, 2012 ERCOT CSWG/RCWG Meeting
18
Types of Errors for Previous Price Corrections
Scenario Data Issues/Examples
Procedure Issue
Incorrect monitor/ secure flag causing invalid constraint (11/7/11)
Data transfer from MIINF staging tables to MFMASTER issue was affected by purging of the MIINF Audit Control Table entries within 7 days (1/7/12)
Telemetry error
SCED intervals failed due to huge telemetered MW value (8/12/11)
Fat finger inputs
Wrong offset (3/25/11)
DAM Operator mistakenly ran phase 2 validation for 3/8/2012 on 3/8/2012 @ 7:30am (3/8/12)
May 11, 2012 ERCOT CSWG/RCWG Meeting
19
Types of Errors for Previous Price Corrections
Scenario Software Issues/Examples
Software error
Incorrect RTRMPR calculation (4/1/11, 4/12/11)
LCCRN Resources with NA status and non-zero BP were treated as offline (4/11/11, 5/10/11)
Software Error in DAM NSM (5/11/11)
Constraint missing in SCED due to an EMS issue which happens when operator activate/deactivate constraints in TCM before RTCA run and then if the RTCA run is aborted by running RT Sequence manually (5/11/11)
SCED failed due to issues in capped and bounded curve logic (5/12/11)
Incorrect EB Shift Factors caused by EMS defect (10/25/11, 10/26/11, 10/27/11, 11/8/11, 11/9/11, 11/11/11)
Incorrect EB Shift Factors caused by EMS defect (11/17/11, 11/18/11)
May 11, 2012 ERCOT CSWG/RCWG Meeting
20
Types of Errors for Previous Price Corrections
Scenario Software Issues/Examples
Software error
GTBD Replication not in place. Wrong GTBD. (7/15/11)
Software Error in DAM DSP (10/17/11-01/21/11, 10/24/11-20/27/12)
Due to MMS defect, DAM LMP was wrongly assigned to the system lambda (12/6/11)
Software Error in DAM NSM post-process (12/4/10, 12/3/10, 4/15/11, 4/8/11, 4/9/11, 4/10/11, 4/12/11, 8/25/11, 9/3/11, 9/5/11, 9/8/11, 2/10/12, 2/11/12, 3/7/12)
May 11, 2012 ERCOT CSWG/RCWG Meeting
21
Why Is Price Correction Needed for Planned Events
• The calculation of Real Time Market Settlement Point Prices (SPPs) was Base Point weighted until the implementation of NPRR 326 & 355 on Feb 24, 2012. Even if everything went perfectly during a planned event, a price correction might still be needed.
• The calculation of Real-Time Price for the Energy Metered for each Resource (RTRMPRs ) remains Base Point weighted. Consequently price corrections may still be needed for future planned events even if they are accomplished perfectly.
• During planned events, SCED inputs may be stale or missing, or Base Points may not be telemetered to Market Participants due to data transfer issues. Consequently SCED LMPs and Base Points can be incorrect or inconsistent with what Market Participants have received. Price corrections are needed for such cases as well.
ERCOT Board MeetingApr 19, 2011
22
Types of Data Errors for Previous Price Corrections
Input data error o Incorrect/incomplete cost data, SF data, EBNRT, SPS,
monitor flago Stale/incorrect GTBD or telemetryo Incomplete list of de-energized buseso Dropping constraints
Output data error o Data transfer issues resulting in Base Points not being
telemetered to Market Participantso Incorrect/incomplete data transfero Price recalculation error
Software erroro MMS defects
System failure infrastructureo Un-planned outages (Systems, Applications, Databases,
ICCP telemetry)o Planned outages (Site failovers, Software releases)
May 11, 2012 ERCOT CSWG/RCWG Meeting
23
FYI
• All market notices on price investigation and corrections can be found at: http://lists.ercot.com/scripts/wa-ercot.exe?A0=NOTICE_SETTLEMENTS
• NPRR456, Posting of Heuristic Table
• Database Load Schedule:http://www.ercot.com/gridinfo/transmission/opsys-change-schedule.html
May 11, 2012 ERCOT CSWG/RCWG Meeting
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