Gareth Lim Manager, Model Engineering

1. Gareth LimManager, Model Engineering WBRTF Data Processing: WECC RC Observations & Implementation of Changes in the WSM Model May 31st, 2013

2. WBRTF Submittals • Phases: • Phase 0: Mapping Data • Phase 1: Generation & Generator Step-Up (GSU) Transformer Data • Phase 2: System Transformer Data • Phase 3: Transmission Line Data

3. WBRTF Submittal Status • Submittal Status: • APS – GEN, GSU • AVA – GEN, GSU • BC-HYD – GEN, GSU • CFE – GEN, GSU, XF, LINE • IPCO – GEN, GSU • LADWP – GEN, GSU • PACE – GEN, GSU • PGE – GEN, GSU, XF, LINE, MAP • PNM – GEN, GSU • PSE – GEN • SCE – GEN • SCPD – GEN, GSU • SRP – GEN, GSU, LINE • TEP – GEN, GSU • TPWR – MAP

4. WBRTF Implementation Status

5. WBRTF Submittals

6. Observations: Data Discrepancies • Type of Data Provided • Pmax differences (Potentially Gross vs. Net Issue) • Example: SRP Santan Unit 5S WBRTF Pmax submitted = 250 MW, ICCP Maximum measurement = 265.4 MW • Impact: Causes potential MW mismatches in State Estimator solution when compared with MW measurements. Potential conflicting requests from RCs / Shift Engineers to change Pmax values due to MW measurement mismatches • Pmax differences (Incorrect data in WBRTF data) • Example: BC-Hydro Dokiwind Wind Units WBRTF Pmax submitted = 0 MW • Impact: Causes potential MW mismatches inState Estimator solution

7. Observations: Data Discrepancies • Type of Data Provided • Pmin differences • WSM Model is used in real-time operational models, which will have situations where generating units are ramping up and ramping down with generation output below its Operational Pmin (could be for several hours – depending on unit) • Impact: Causes MW mismatches in State Estimator solution when compared with MW measurements. Potential conflicting requests from RCs / Shift Engineers to change Pmin values due to MW measurement mismatches

8. Observations: Data Discrepancies • Type of Data Provided • Qmax / Qmin differences • Example: BC-Hydro Units WBRTF Qmax / Qmin values EMS BC-Hydro Netmom have capability curves • Impact: Qmax / Qmin values not applied, as capability curves will override • MVA Rating differences • Example: PSE Bakersrvu Units WBRTF Pmax > MBase value WSM modeling requires MVA > Pmax • Impact: Violates current WSM modeling practices – Potential issues with DTS application

9. Observations: Data Discrepancies • Mapping Quality • WBRTF Submitter maps 1 winding of a 3 winding transformer data directly to the WSM 2-winding transformer • Impact: Requires additional thorough review by WECC Modeling Engineers to double-check against WECC Basecase • WBRTF Submitter maps series capacitors to lines • Example: SRP Coronado – Silver King 500kV line. Coronado-side series capacitor mapped to WSM Line • WBRTF Submitter maps incorrect equipment • Example: BC-Hydro Bridge1 360/14 kV GSU 1B mapped to 14/14 kV GSU in WECC Basecase • Impact: Requires additional thorough review by WECC Modeling Engineers to ensure mapping correct

10. Observations: Data Discrepancies • Different Modeling Detail – GSU • WECC Basecase includes additional step-up for wind turbines • Example: BC Hydro Bearmtnw 138/35 kV – WECC Basecase also includes step-up 35/0.4 kV • Impact: Requires additional thorough review by WECC Modeling Engineers to proper mapping & exclude these additional modeling • WECC Basecase includes generator bus kV difference • Example: SRP Aguafria Unit 4 – Planning = 13.8 kV, WSM = 13 kV, SRP Operations = 13.2 kV • Impact: Requires additional thorough review by WECC Modeling Engineers to coordinate with various folks (Planning & Operations)

11. Observations: Data Discrepancies • Different Modeling Detail – GSU • WECC Basecase includes multiple step-up for each unit, WSM has only one step-up transformer • Example: PACE Emery (Hunter) Units #1 & 2 GSU 345/24 kV – WECC Basecase has two parallel GSU transformers for each unit, WSM has one GSU for each unit. • Impact: Requires additional thorough review by WECC Modeling Engineers to add the appropriate topological detail • Different Modeling Detail – Transformers • WECC Basecase models 3-winding transformers (with disconnected tertiary), WSM models 2-winding transformers • Example: BC-Hydro Transformers (approximately 100 xfmrs) • Impact: Requires additional thorough review by WECC Modeling Engineers to add the appropriate topological detail

12. Observations: Data Discrepancies • Different Modeling Detail – Transformers • WECC Basecase model lower kV system equivalized in WSM model • Example: BC-Hydro 60kV system • Impact: Requires additional thorough review by WECC Modeling Engineers to add the appropriate topological detail • Different Modeling Detail – Generators • WECC Basecase model units in the lower kV system equivalized in WSM model • Example: BC-Hydro generating units connected to the BC-Hydro 60kV system • Impact: Requires additional thorough review by WECC Modeling Engineers to add the appropriate topological detail

13. Observations: Data Discrepancies • Different Base • WBRTF Submitter provides transformer impedance data in Transformer MVA Base, and compares with WSM 100 MVA Base • Impact: Requires additional thorough review by WECC Modeling Engineers to identify MVA Base differences, and convert data to 100 MVA Base • WBRTF Submitter requests that Transformer MVA Base be changed in WSM model to match WECC Basecase

14. Observations: Data Discrepancies • LTC Tap Changer step sizes • WBRTF Submitter submits LTC Tap Changer step sizes that is combination of transformer off-nominal kV, and tap size • Impact: Lose granularity of modeling off-nominal kV and tap size independently. Conflicts with previously validated tap modeling data. • LTC Tap Changer location • WBRTF Submitter submits LTC Tap Changer on the To Bus side, and request WSM to swap From-To bus • EMS Model requires LTC Tap Changer to be modeled on From side. • Impact: Potential modeling issues with Tap Changer remodeled on To side, hence not providing LTC support in EMS

15. Observations: Data Discrepancies • EMS Mapping limitations • WBRTF Submitter submits WECC Basecase Bus Name > 8 characters (PSLF max = 12 characters). EMS model Translation table TRANSID limited to 8 characters. • Potential issue with Bus Numbers as well – EMS model Translation table TRANSNUM limited to 5 numbers, PSLF max = 6 numbers • Impact: Requires Modeling Engineer to “tweak” Translation IDs to meet EMS character limitation. Mapping discrepancies continue to exist.

16. Observations: Software Limitations • EMS-to-PTI Raw File Conversion Software Bug • Recently identified sofware bug where Exported Bus Name defaults to the EMS Substation ID, instead of the TRANSID mapping provided • WSM model used for comparison is a snapshot of the state of the system, and may have split busses – resulting in busses with duplicate Bus Numbers defaulting to auto-generated unused Bus Number

17. Observations: Data Discrepancies • General comments from EMS Modeling / Operations contacts • “Where are you getting this data?” • “The generator parameters are different because we have been updating the operations (EMS) model parameters based on telemetry observations – so if there are discrepancies, use the operations (EMS) model values” • “Our operations model data does not always agree with the planning model data”

18. Implementation Flowchart

19. WECC RC Resource Concerns • Extensive resources required to perform Data Validation • Example: 1 BA, 1 DeviceType (50-100 equipments) • Basic review (finding EMS Names) + Template creation: 2 hrs • Rio Script creation & Netmom validation: 1 hr • Powerflow Testing: 0.5 hr • E-terrasource Modeling: 3 hrs – 20 hours (depending on equipment) • Thorough review (Mapping verification & Side-by-side data validation using Comparison Tool): 2.5 hours • Excludes Discrepancies requiring additional investigation: 20-30% for Lines & Transformers, 10-20% for GSUs • Additional resource needed to test submitted data changes, and prepare necessary testing documentations

20. WECC RC Resource Concerns • Multiple Testing Iterations require multiple resources • Rio Script Creation  Powerflow Testing  State Estimator Testing  Issues Identified  Rio Script Modification  …. Restart Process….. • Example (DB46) Resource Usage: • 9 Set of Changes: BC-Hydro (Gen, GSU, Transformer), PACE (Gen, GSU), PSE (Gen), SRP (Gen, GSU, Lines) • Modeling Engineer (Thorough Review, Rio & Troubleshooting) – 45 hours • Model Engineering Manager (Discrepancies Discussion, Troubleshooting) – 10 hours • EMS Applications Engineer (Testing, Test Documentation) – 24 hours • Excludes: (1) E-terrasource model update, (2) Model discrepancies requiring additional investigation, (3) Model changes related to different modeling details

21. Recommendations • Operations Agreement & Sign-Off: WBRTF reviewer requests internal review by Operations personnel for verification prior to submitting data to WECC RC for update • Added Benefit: Reconciliation of Entity’s own Operations and Planning Model • Improved Data Quality: WBRTF reviewer reviews data differences, and not just providing differences • Data Source Identification: WBRTF reviewer indicates source of Planning model data – WECC Planning Basecase or Entity’s Internal Planning Model

22. Recommendations • Additional Supporting Data: WBRTF reviewer provides additional supporting operational modeling details (e.g. generating unit capability curves, transformer tap tables - showing ranges) • Data Submittal Template enhancements: • Example: Split Transformer 3-Winding data from Transformer 2-Winding data

23. Bottom Line • Need Better Quality Data • Need Closer Coordination with Entities Internal Operations staff prior to data submittal • Set Expectations that modeling review and changes to the WSM Model is Resource Intensive (equivalent to multiple routine model update requests)

24. Gareth Lim Manager of Model Engineering glim@wecc.biz Questions?