Path Rating Catalog 2013 - Western Electricity Coordinating Council

Revised January 2013
III-17. TOT3 Archer Interconnection
Project
Accepted Rating
Existing Rating
Other
Location:
Definition:
Transfer Limit:
The TOT3 Archer Interconnection Project increases the rating of Path 36, and
TOT 3 on the border between Northeast Colorado and Southeast Wyoming
Sum of the flows on the following transmission lines:
Line
Metered End
Archer-Ault 230 kV
Archer
Laramie River-Ault 345 kV Laramie River
Wayne Child-Story 345 kV Wayne Child
Cheyenne-Owl Creek 115 kV Cheyenne
Sidney-Sterling 115 kV
Sidney
Sidney-Spring Canyon 230 kV Sidney
Cheyenne-Ault 230 kV
Cheyenne
North to South: 1843 MW
South to North: undefined
Critical
Disturbance
that limits the
transfer
capability:
When:
System
Conditions:
Study Criteria:
The critical disturbances and limiting elements vary with the various
generation scenarios. The TOT3 1844 limit is determined with LRS=570
MW, Pawnee=280 MW, and DC Ties=300MW E-W. At this generation point
the critical outage is the Laramie River-Ault 345 kV line, and the voltage in
the Cheyenne 115 kV area is limiting. The Laramie River-Ault 345 kV and
Laramie River-Wayne Child 345 kV lines may require upgrades to
accommodate this TOT3 transfer.
Tri-State anticipates an in service date of June 2016. TSGT plans to increase
the TOT3 transfer capability by an additional 163 MW. The Archer
Interconnection project includes tapping the LRS-Story 345 kV line at
Archer, a new 345/230 kV transformer known as Wayne Child, a Wayne
Child – Archer 230 kV line and Wayne Child-Cheyenne 230 kV line.
The transfer limit is impacted by local area generation, and the direction and
magnitude of DC tie flows. There are 24 points on the TOT3 generation
matrix. As the WECC Path Rating Process proceeds the Maximum TOT3
transfer limit for each of the 24 generation points will be determined.
System intact:
• Per unit voltages between 0.95 and 1.05 p.u.
• All lines and transformers loaded to less than continuous rating.
Single contingency outage conditions:
• Per unit voltages between 0.90 p.u. and 1.10 p.u.
• All lines loaded to less than 15-minute emergency ratings.
• All transformers loaded to less than 30-minute emergency ratings.
• Transient voltage swings down to 0.7 p.u. permitted.
PART VI Item 1-254