Path Rating Catalog 2013 - Western Electricity Coordinating Council

51. Southern Navajo
Revised December 2011
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:
Northern Arizona
Sum of the flows on the following transmission lines:
Line
Metered End
Moenkopi-Cedar Mt. 500 kV Moenkopi 500 kV
Navajo-Dugas 500 kV
Navajo 500 kV
North to South: 2800 MW
South to North: Undefined
The 2800 MW non-simultaneous rating of Path 51 is due to the emergency
rating of the Yavapai-Willow Lake 230 kV line for N-1 outage of the
Yavapai-Westwing.
The new transfer rating was established in 2009 as described in the report
(Southern Navajo (path 51) Upgrade Project WECC Accepted Rating Report)
performed by APS for the Path 51 Project Rating Review group and the
WATS task force.
Flows on this transfer path have historically been north to south due to the
generation at the Navajo power plant, nearby wind generation and resources
east and west of the plant.
Same as the WECC Reliability Criteria for Transmission System Planning
and NERC/WECC Planning Standards.
None.
None.
The transfer capability is divided amount the following entities:
• Salt River Project 1072 MW
• Arizona Public Service Company 692 MW
• Department of Energy 664 MW
• Tucson Electric Power Company 372 MW
2800 MW
There are no interactions with other WECC paths, however a simultaneous
relationship was identified between Path 51 flows and the Yavapai-Willow
Lake 230 kV line as described by the included nomogram (Fig. 2).
PART VI Item 1-144