Path Rating Catalog 2013 - Western Electricity Coordinating Council

Revised January 2013
III–18. Mountain States Transmission
Intertie
Accepted Rating
Existing Rating
Other
Location:
Definition:
Transfer Limit:
Critical Disturbance
that limits the
transfer capability
When:
System Conditions:
Study Criteria:
Remedial Actions
Required:
Formal Operating
Procedure:
Allocation:
Interaction w/Other
Transfer Paths:
Contact Person:
Between southwest Montana and southern Idaho
500 kV line from Townsend, MT to Midpoint Idaho with a phaseshifting
transformer located near the existing Mill Creek 230 kV
substation. The line will be series compensated at 70%.
North to South: 1,500 MW
South to North: 1100 MW
No limiting contingencies were revealed in the Phase 1 nonsimultaneous
studies. Further study in Phase 2 may or may not alter
the most limiting contingency.
Phase II completed on September 8, 2011 Phase 3 status was
granted by PCC and TSS on September 26, 2011.
The rating was studied under heavy summer and light autumn
conditions with all lines in service.
NERC/WECC Planning standards and criteria
For the loss of MSTI, tripping of the MSTI collector system will be
required. This collector RAS will need to be coordinated with the
Colstrip ATR.
Not Available
NorthWestern Energy
Based on MSTI Phase 2 studies, the following nomogram
relationships have been identified:
MSTI vs. Idaho to Northwest (West to East)
MSTI vs. Borah West
Ryan Munson
NorthWestern Energy
40 E Broadway Street
Butte, MT 59701
Office: (406) 497-3213
Fax: (406) 497-3002
Ryan.Munson@northwestern.com
Eric Bahr
NorthWestern Energy
40 E Broadway Street
Butte, MT 59701
Office: (406) 497-3394
Fax: (406) 497-3002
Eric.Bahr@northwestern.com
PART VI Item 1-256