Tyson Niemann Associate Engineer II Overview Goal Data Used - PowerPoint PPT Presentation

Decreasing Fault Current August 13, 2019 Tyson Niemann Associate Engineer II

Overview • Goal • Data Used • Limitations • Results • Findings • Recommendations and Next Steps 2

Goal • Evaluate the potential fault current in the future based on data received for base case development • To identify potential locations that have dramatically changing in the future 3

Data Used • 2019 Heavy Summer 3 • 2024 Heavy Summer 2 • 2029 Heavy Summer 1 • Location information was extracted from the Geomagnetic Disturbance data collected for TPL-007 • Simulations performed in PowerWorld • 3 Phase balanced bus fault 4

Limitations • Used cases designed for Power Flow to do Short Circuit study • Positive Sequence data only • No Mutual Coupling data • Dynamic data needed for machine impedance • Incomplete location information • Monitored fault current changes of all buses • Results grouped to simplify analysis • Visualization was limited to location information 5

19HS3 -> 24HS3 6

19HS3 -> 29HS1 7

Results • 382 buses had over 1 million amps as their fault current • 1,118 buses had over 100k amps as their fault current • GIS coordinates for 9,285 buses out of 24,548 buses • After filtering all three cases decreasing, <1 mil, with GIS, it leaves 1,147 buses (2,460 if you exclude GIS) 8

Results Continued • 21 buses had 25% difference between 19HS3 and 24HS3 • 35 buses had 10-24% difference between 19HS3 and 24HS3 • 140 buses had 25% difference between 19HS3 and 29HS3 • 90 buses had 10-24% difference between 19HS3 and 24HS3 • 117 buses had 25% difference between 24HS3 and 29HS3 • 46 buses had 10-24% difference between 24HS3 and 24HS3 9

Findings • X” and R” cannot both be 0 • Generally fault current is decreasing in simulations • California was less pronounced than expected • Northwest showed largest changes • Want to understand why • Hypothesis that changes to fault current tied to large generator retirements • Any other ideas? 10

Recommendations/Next Steps • Recommending the System Data Work Group renew efforts to populate X’’ and R’’ accurately • Default X” will be set to 0.12 pu instead of 0/0 and capped at 999 • Further investigation by Planning Coordinators and Transmission Planners in areas with significant >25% • Discussion about best practice for reviewing relay settings when changes are made to system • Same study using short-circuit cases? 11

Contact: Tyson Niemann tniemann@wecc.org 801-819-7687 12

Additional Slides 13