Constraints Competitiveness Tests (CCT) – Annual CCT 2013 Study Result with New Approach

August 2012

Wholesale Market Operations

Constraints Competitiveness Tests (CCT) –Annual CCT 2013 Study Result with New Approach

Market Support and Analysis

2

Changes from Current Approach to New Approach

ERCOT PublicAugust 2012

Current Approach New Approach

Shift factor referenceImport and export

terminalsDistributed load

ECI impactProduct of capacity and

shift factorProduct of capacity and

square of shift factor

ECI significant threshold1/3 of maximum SF as

well as not contributed to worst flow

Minimum of absolute 0.02 value and 1/3 of

maximum SF

Overload-ability (worst flow)

Accumulate generation impact from worst SF until meet system total

load impact +/- line limit, then compare

accumulated generation capacity to system total

load

Accumulate generation capacity from worst SF until meet system total

load, then compare accumulated generation

impact to line limit

Wind capacity available ratio

Expected on-peak output 0% for those with SF<0

3

Implemented CCT Logic for this Study

• A constraint is “Competitive” if– Constraint can not be overloaded under worst case scenario

OR – Combination of

• There are resources with absolute Shift Factor >=2 %• AND positive-SF ECI of squared SF with min(0.02, 1/3)

threshold < 2500• AND negative-SF ECI of squared SF with min(0.02, 1/3)

threshold < 2000• AND no pivotal player exists

• Otherwise, it is “Non-Competitive”• An option up for consideration is ignoring the “overloaded

under worst case scenario” check– May be appropriate because we are only analyzing one month,

which is a peak load month, as oppose to 12 monthly cases


4

Constraint Sets and Models used in Annual CCT Study

• Models– SSWG 2013 Summer case (dated 2/27/2012) with CRR Annual

Auction August 2013 constraint and contingency definitions (dated 9/28/2011)

– CRR Auction August 2013 case (dated 7/23/2012)– Basic picture on both models

• Total generation capacity about 94,000 MW from registration data

• Total load about 74,000 MW from SSWG 2013 Summer case

• Entire topology considered, no outages on lines and transformers

• Constraint Sets– SCED historical constraints since go-live (693 distinct

constraints, all evaluated for both directions)– CSC/CRE (332 distinct constraints, all evaluated for both

directions)


5

Result on SCED Historical Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], OL Flag Check)


Current Approach

New ApproachSSWG Model

CountSSWG Model Percentage

CompetitiveCompetitive 1009 72.80%

Non-competitive 232 16.74%

Non-competitiveCompetitive 14 1.01%


Total 1386 100.00%

Current Approach

New ApproachCRR Auction Model Count

CRR Auction Model

Percentage





Total 1352 100.00%

6

Result on CSC/CRE Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], OL Flag Check)


Current Approach







Total 664 100.00%

Current Approach


CRR Auction Model

Percentage





Total 664 100.00%

7

Result on SCED Historical Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], No OL Flag Check)


Current Approach







Total 1386 100.00%

Current Approach


CRR Auction Model

Percentage





Total 1352 100.00%

8

Result on CSC/CRE Constraints (Zero-out Negative Wind Flow, ECI Threshold [2000,2500], No OL Flag Check)


Current Approach







Total 664 100.00%

Current Approach


CRR Auction Model

Percentage





Total 664 100.00%

9

Summary of Study Results – Number of Competitive Constraints


ECI Threshold Option ECI Threshold [2000,2500] ECI Threshold [2500,3000]

Overload Flag Check Option OL Flag Check No OL Flag OL Flag Check No OL Flag

Constraint Set ModelComp. or Non-

Comp.Count Pctg Count Pctg Count Pctg Count Pctg

SCED Historical

SSWGCompetitive 1023 73.81% 39 2.82% 1037 74.82% 70 5.05%

Non-Competitive 363 26.19% 1347 97.18% 349 25.18% 1316 94.95%

CRR AuctionCompetitive 852 63.02% 38 2.81% 879 65.01% 85 6.29%

Non-Competitive 500 36.99% 1314 97.19% 473 34.98% 1267 93.71%

CSC/CRE

SSWGCompetitive 561 84.49% 211 31.78% 621 93.53% 311 46.84%

Non-Competitive 103 15.51% 453 68.22% 43 6.47% 353 53.16%

CRR AuctionCompetitive 516 77.71% 211 31.77% 608 91.57% 334 50.31%

Non-Competitive 148 22.28% 453 68.22% 56 8.43% 330 49.70%

10

Inconsistent Results Between the 2 Models (Switch between Competitive/Non-existing and Non-competitive)


Dataset Description Count

cscCSC/CRE constraint set existing in both SSWG 2013

model and CRR auction Aug 2013 model45

sced_crraugSCED historical constraint set existing only in CRR

auction Aug 2013 model56

sced_sswgSCED historical constraint set existing only in SSWG

2013 model38

scedhistSCED historical constraint set existing in both SSWG

2013 model and CRR auction Aug 2013 model189

Total 328

(Zero-out Negative Wind Flow, ECI Threshold [2000,2500], OL Flag Check)

11

Causes of Inconsistent Results between the 2 Models

• Actual topology change– Results in shift factor change– Results in ECI change

• Line limit change– Results in overload-ability change– Result in PPI change once compared pivotal flow to line limit


12

Concerns during Annual CCT Study

• DC-Ties (all DC-Ties have been considered in the study with entity as ERCOT)

• Only the decision making entity was considered for this study, not Affiliates

• Impact of peak load in cases that were studied– Significantly reduced the number of overload-able constraints, – A high-ECI constraint can be competitive just because it won’t

be overloaded in the worst case when generators with SF<0 are used to meet peak load

• Should negative WGR shift factors be included in the shift factor cut-off even if the MWs are considered to be 0


13

Additional Material


14

Summary of all New Study Results


ECI Threshold Option ECI Threshold [2000,2500] ECI Threshold [2500,3000]

Overload Flag Check Option OL Flag Check No OL Flag OL Flag Check No OL Flag

Constraint Set Model Pattern Count Pctg Count Pctg Count Pctg Count Pctg

SCED Historical

SSWG

Comp to Comp 1009 72.80% 26 1.88% 1033 74.53% 67 4.83%

Comp to Non-Comp 232 16.74% 1215 87.66% 267 19.26% 1233 88.96%

Non-Comp to Comp 14 1.01% 13 0.94% 4 0.29% 3 0.22%

Non-Comp to Non-Comp 131 9.45% 132 9.52% 82 5.92% 83 5.99%

CRR Auction

Comp to Comp 845 62.50% 33 2.44% 879 65.01% 85 6.29%

Comp to Non-Comp 307 22.71% 1119 82.77% 359 26.55% 1153 85.28%

Non-Comp to Comp 7 0.52% 5 0.37% 0 0.00% 0 0.00%


CSC/CRE

SSWG

Comp to Comp 548 82.53% 199 29.97% 610 91.87% 300 45.18%

Comp to Non-Comp 53 7.98% 402 60.54% 36 5.42% 346 52.11%

Non-Comp to Comp 13 1.96% 12 1.81% 11 1.66% 11 1.66%


CRR Auction

Comp to Comp 503 75.75% 204 30.72% 581 87.50% 309 46.54%

Comp to Non-Comp 90 13.55% 389 58.58% 52 7.83% 324 48.80%

Non-Comp to Comp 13 1.96% 7 1.05% 27 4.07% 25 3.77%


15

Results Presented During 8/6 CMWG Meeting

• For the results presented at the 8/6 CMWG Meetings, the ECI thresholds that were used were 3000 and 2500 (as oppose to 2500 and 2000)

• For the wind capacity ratio– ECI: 0% for the WGRs with shift factors < 0– PPI: 100% for all (impact on constraint considered to be 0)


16


• Results on SCED Historical Constraints – Overload Check


Current Approach New ApproachSSWG Model






Total 1386 100.00%

Current Approach New ApproachCRR Auction Model Count

CRR Auction Model Percentage





Total 1352 100.00%

17


• Results on CSC/CRE Constraints – Overload Check








Total 664 100.00%







Total 664 100.00%

18


• Results on SCED Historical Constraints – No Overload Check








Total 1386 100.00%







Total 1352 100.00%

19


• Results on CSC/CRE Constraints – No Overload Check








Total 664 100.00%







Total 664 100.00%

20

Other Previously Discussed Results

• If at another Load Profile - Compared to Previous Study in May 2012– Out of 542 CSC/CRE constraints, 522 are competitive and 20

are non-competitive with current CCT approach. Note it considers ECI, PPI and worst case flow.

– While with proposed min(0.02, 1/3) squared SF approach, out of 542 CSC/CRE constraints, 290 are competitive and 252 are non-competitive. Note it considers ECI, PPI and worst case flow as well.

– The competitive ratio for CSC set reduces from 96% to 53%.– Note that this version of result is based on DCCT 11/30/2011.


Documents

Constraints Competitiveness Tests (CCT) – Annual CCT 2013 Study Result with New Approach