1. SPWG SHORT CIRCUIT CASE BUILDING AND DEVELOPMENT - 2014 July 17, 2014 Qiuli Yu and Jay Teixeira ERCOT

2. 2 Topics Case Building Process for Current Year and Future Year Cases o Current Year Case Process o Future Year Case Process o Software Requirement/Update Case Development and Achievement in 2014 o Generator Synchronization with SSWG o Sequence Impedance o Grounding Impedance o Voltage Profile o Current Limit Wind Farm Modeling—WTG Equivalent Circuit Jul 17, 2014

3. 3 Case Building Process – Current Year Time Span o From Mid-December (Previous Year) to Mid-April (Current Year) o Total 6 Passes – Pass 0, 1-4, and Final Pass o Two Weeks for TSP to Submit Change Files o One Week for ERCOT to Develop Short Circuit Model Base Case o Future Year Final Pass created last year o Example: 2015 CY base case = SPWG_2015_FY_UPDATED_07032014_FINAL July 17, 2014

4. 4 Case Building Process – Future Year Time Span o From Mid-April (Current Year) to Mid-July (Current Year) o Total 6 Passes – Pass 0,1-4, and Final Pass o One Week for TSP to Submit Change Files o One Week for ERCOT to Develop Short Circuit Model Base Case o Current Year Final Pass created in current year o Example: 2016 FY base case = SPWG_2015_CY_UPDATED_04xx2015_FINAL July 17, 2014

5. 5 Summary – Base Cases for CY and FY This Year’s Base Case Base Case to be Used for Creating the New Base Case When the Base Case is Created 2015_CY SPWG_2015_FY_Updated_07032014_Final.DXT Last Year (2014) 2016_FY SPWG_2015_CY_Updated_xxxx2015_Final.DXT This Year (2015) 2017_FY SPWG_2015_CY_Updated_xxxx2015_Final.DXT This Year (2015) 2018_FY SPWG_2015_CY_Updated_xxxx2015_Final.DXT This Year (2015) 2019_FY SPWG_2015_CY_Updated_xxxx2015_Final.DXT This Year (2015) 2020_FYSPWG_2015_CY_Updated_xxxx2015_Final.DXTThis Year (2015) July 17, 2014

6. 6 Summary – Change Files for 2016-2020 FY Cases 2015 FY 2016 FY 2016 CHF 2015 FY 2017 FY 2017 CHF 2015 FY 2018 FY 2018 CHF 2015 FY 2019 FY 2019 CHF 2015 CY 2016 CHF 2016 FY 2015 CY 2017 CHF 2017 FY Cases Built Last Year July 17, 2014

7. 7 Software Requirement and update ERCOT and TSPs: o PSSE v33 o ASPEN OneLiner V12.4 ERCOT: o RARF Database o MODFileBuilder v33 July 17, 2014

8. 8 Case Development and Achievement in 2014 Add generators to synchronize with SSWG cases o Grandview, PH1, PH2, WindThorst, Stephens Ranch, Spinning Spur Wind 3, Long Horn, RenTech Project, Hereford,…… o Most new gens are wind farms o Some gens with incomplete RARF data have not been modeled Sequence Impedance Data (P.U.) o Come from RARF submitted by REs o Some verification rules: X”<X’<X R 0 &X 0 may be 99999 for WTG o Process: Query out from RARF database and manually copy/paste to PSSE file Jul 17, 2014 Direct Axis Subtransient Reactance (Saturated) X" Direct Axis Transient Reactance (Saturated) X' Positive Sequence resistance R 1 Positive Sequence reactance X 1 Negative Sequence resistance R 2 Negative Sequence reactance X 2 Zero Sequence resistance R 0 Zero Sequence reactance X 0

9. 9 Case Development and Achievement in 2014 (continue…) July 17, 2014

10. 10 Case Development and Achievement in 2014 (continue…) Voltage Profile o Voltage profile is the Vsched (pu) in the Machine Tab in PSSE o Come from SSWG base case (PSSE raw file) o Process: Manually copy from SSWG base case and paste into SPWG PSSE file July 17, 2014 Bus NumberBus NameId Area Num Area NameCodeVSched (pu) 1007AAAA11XXXX41 1031BBBB11XXXX41 1035CCCC11XXXX41 1036DDDD11XXXX41 1037EEEE11XXXX41 1038FFFF11XXXX11 1349GGGG1901YYYY21.014 1863HHHH11XXXX41 6034IIIIF6ZZZZ21.025 6103JJJJEQ14QQQQ31.045 7018KKKKN27RRRR21

11. 11 Case Development and Achievement in 2014 (continue…) July 17, 2014

12. 12 Wind Farm Modeling—WTG at Different kV Currently WTG are modeled at different kV levels in SPWG: o 0.575 kV o 0.690 kV o 34.5 kV July 17, 2014

13. 13 Wind Farm Modeling—WTG Equivalent Circuit (Future Work) Equivalent Circuit and Parameters (One Feeder): Individual WTG will be aggregated per feeders Topology and Parameters – RARF Hope to complete December of 2014, depending on RARF data submission July 17, 2014

14. 14 Possible Methods for WTG Equivalent Circuit Development Method 1 – Fault Current Simulation Using PowerWorld July 17, 2014 Fault Current Magnitude: 1.468 p.u. Fault Current Angle:-88.98 degrees

15. 15 Possible Methods for WTG Equivalent Circuit Development Method 2 – Equivalent impedance calculation based on Wind Farm topology and collector system parameters July 17, 2014

16. 16 Possible Methods for WTG Equivalent Circuit Development Method 3 – Use equivalent network function in PSSE/PowerWorld? Any Comments? July 17, 2014

17. 17 Questions July 17, 2014