Path Rating Catalog 2013 - Western Electricity Coordinating Council

82. TotBeast
Revised January 2013
Accepted Rating
Existing Rating
Other
Location:
Definition:
Transfer Limit:
Critical
Disturbance
that limits the
transfer
capability:
When:
System
Conditions:
Study Criteria:
Remedial
Actions
Required:
Southwest Idaho and Eastern Oregon/Washington and Northern Idaho
Sum of the flows on the following lines:
Line
Metered End
Summer Lake - Hemingway 500 kV
Hemingway
Brownlee-Boise Bench #1 230 kV
Brownlee
Brownlee-Boise Bench #2 230 kV
Brownlee
Brownlee-Boise Bench #3 230 kV
Brownlee
Brownlee-Horse Flat #4 230 kV
Brownlee
Brownlee-Ontario 230kV
Brownlee
Oxbow-Starkey 138kV
Oxbow
Quartz-Ontario 138kV
Quartz
West to East: 2465 MW
1915 MW Brownlee East (Path 55)
550 MW Hemingway-Summer Lake 500 kV (Path 75)
Post transient reactive margin at the Boise Bench 230kV following the loss of
the Hemingway-Summer Lake 500kV line, or the loss of two Jim Bridger
lines with tripping of two Jim Bridger Units, or the loss of two Brownlee-
Boise Bench 230kV lines. Thermal limits on the remaining two Brownlee-
Boise Bench 230kV lines for loss of the other two lines.
The thermal overload of the Lolo-Oxbow 230kV line is the limiting condition
for an outage of the Hemingway-Summer Lake 500kV line.
This is an expanded version of the Brownlee East path (#55) that now also
includes the Hemingway-Summer Lake path (#75) in its West to East
direction.
As this is only a combined rating of the other two paths which already have
“accepted” ratings; study results supporting this path’s “other” rating are
based on rating / OTC studies performed on the two component paths.
A description of the rating history of each of the two paths can be found in
the corresponding section for each path in this path catalog.
The 2465 MW west to east transfer rating on TotBeast was studied with high
imports on Idaho-Northwest (Path 14) , Brownlee East (Path 55) flows
(1915MW) simultaneous with -550MW on the Hemingway-Summer Lake
500kV line (Path 75), high T E Roach Complex generation at peak summer
load conditions. This generally coincides with high hydro conditions in the
Northwest with low to moderate eastern thermal resources.
NERC/WECC Reliability Criteria For Transmission System Planning
At high flows east of Brownlee, the loss of two Brownlee-Boise Bench
230kV lines requires overload mitigation measure of bypassing ½ series
compensation in the remaining two Brownlee-Boise Bench 230kV lines.
PART VI Item 1-206