Path Rating Catalog 2013 - Western Electricity Coordinating Council

Revised January 2013
4. West of Cascades - North
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:
Central Washington
Sum of the flows on the following lines:
Line Owner Metered End
Chief Joseph-Monroe 500 kV BPA Chief Joseph
Schultz-Raver 1, 3, 4 500 kV BPA Schultz
Chief Joe-Snohomish 345 kV lines 3&4 BPA Chief Joseph
Rocky Reach-Maple Valley 345 kV BPA Rocky Reach
Coulee-Olympia 287 kV BPA Coulee
Rocky Reach-Cascade 230 kV PSE Rocky Reach
Bettas Road-Covington No. 1 230 kV BPA Bettas Road
Schultz-Echo Lake 500 kV BPA Schultz
The transfer limit is approximately 10,200 MW and is thermal and voltage
stability limited.
The two critical outages include the single line outage of the Chief Joseph-
Monroe 500 kV line under “extra heavy” winter peak load levels and the
double outage of the Schultz-Raver #1 and Schultz-Echo Lake #1 500 kV
lines under normal winter peak load levels.
BPA completed a path study in 2011 and is currently completing an updated
study in 2013.
Generally, to achieve high West of Cascades - North flows, the Northwest
region must experience an “extra heavy” winter load condition. These
unusual “Arctic storm” conditions have occurred on several occasions in the
past. High flows can also occur during Spring or when renewable generation
in the east is operating when many Westside thermal units are off-line and
the power is coming from east of the Cascades.
All applicable BPA and NERC/WECC Standards.
None. Some Puget Sound Area entities have automatic under-voltage load
tripping in place to trip up to 15% of their loads as a safety net for Extreme
Events.
BPA Dispatch Standing Order 322, “Voltage Collapse Mitigation Procedures
for the Puget Sound Area.”
All of the capacity is allocated to BPA and PSE.
None
PART VI Item 1-13