Path Rating Catalog 2013 - Western Electricity Coordinating Council

33. Bonanza West
Revised December 2010
Accepted Rating
Existing Rating
Other
Location:
Definition:
Transfer Limit:
Critical
Disturbance
that limits the
transfer
capability:
When:
System
Conditions:
Northeast Utah to Central Utah
Sum of the flows on the following transmission lines:
Line
Metered End
Bonanza-Mona 345 kV
Mona
Upalco-Carbon 138 kV
Carbon
East to West: 785 MW
West to East: Not defined
Depending on local generation levels and the flows on underlying 138 kV
facilities, the real-time rating can vary up to 785 MW. Typically the realtime
rating is about 735 MW.
Bonanza-Mona 345 kV outage. Based on modeled system conditions,
outage results in post-transient overload on Upalco-Carbon 138 kV and/or
the Flaming Gorge 138/230 kV transformer.
December 1990. The rating was established with the publication of the
“Bears Ears-Bonanza 345 kV Line Operating Study Report,” March 1990,
and with the upgrading of current transformers at Mona. The operating
study was conducted jointly by the following entities:
Western Area Power Administration - Salt Lake City, Golden, Montrose
Tri-State Generation & Transmission Association, Inc.
Utah Associated Municipal Power Systems
Deseret Generation & Transmission Co-operative
Platte River Power Authority
Salt River Project
PacifiCorp
Colorado-Ute Electric Association
The rating is independent of transfer levels between major areas of WECC,
although the actual flow is heavily impacted by inadvertent flows. This
rating is verified each year by Deseret in its TPL Study Program. The
transfer limit is impacted by local area generation and load levels.
Historically, flows have been east to west across the path.
Study Criteria: • Steady-state pre-disturbance voltages between 0.95 p.u. and 1.05 p.u.
• All lines and transformers loaded to less than continuous rating.
• Post-disturbance 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 110% of maximum continuous
ratings.
• Transient voltage swings down to 0.70 p.u. permitted, except for
Utah Power facilities which were limited to 0.80 p.u. and Deseret
G&T’s Rangely bus which is limited to 0.75 p.u.
PART VI Item 1-93