Path Rating Catalog 2013 - Western Electricity Coordinating Council

III-9. TOT 4A (Pre-Gateway)
Location:
Definition:
Transfer Limit:
Critical
Disturbance
that limits the
transfer
capability:
Added January 2013
Accepted Rating
Existing Rating
Other
Southwest Wyoming
Sum of the flows on the following transmission lines:
Line
Metered End
Riverton-Wyopo 230 kV
Riverton
Miners-Platte 230 kV
Miners
Spence-Mustang 230 kV
Spence
Northeast to Southwest: 937 MW (Non-simultaneous)
Southwest to Northeast: Not defined
Depending on flows on the adjacent TOT 4B path, the real-time rating can
range between a minimum of 0 MW and a maximum of 937 MW
(Reference attachment). Typically, the real-time rating centers around 650
MW.
The critical disturbances and limiting elements vary with the various
points on the nomogram. Reference attachment for further information.
When: Rating Study Approved on 10/8/2010
System
Conditions:
Study Criteria:
Remedial
Actions
Required:
Formal
Operating
Procedure:
Allocation:
Interaction
w/Other
Transfer Paths:
This rating is independent of transfer levels between major areas of
WECC. Historically, the flows have all been northeast to southwest across
the path.
(Summary)
System intact:
• Per unit voltages between 0.95 p.u. and 1.05 p.u.
• All lines and transformers loaded to less than continuous rating.
Single contingency outage conditions:
• Per unit voltages between 0.90 p.u. and 1.10 p.u.
• All facilities loaded to less than 100% of emergency ratings.
Remedial actions are required to achieve the rated transfer capability.
Following an outage, all overloaded lines and transformers must have their
loading reduced to continuous ratings within 15 minutes. This is
accomplished by reducing schedules and adjusting generation.
There is a formal operating proceduredated 4/12/1991. PAC is the
operating agent and uses real-time flows to monitor the path.
PAC has the entire transfer capability of the path.
See attachment
PART VI Item 1-230