Path Rating Catalog 2013 - Western Electricity Coordinating Council

Revised February 2007
48. Northern New Mexico (NM2)
Accepted Rating
Existing Rating
Other
Location:
Definition:
Transfer Limit:
Northern New Mexico
Sum of flows on the following transmission elements:
Element
Metered End
Four Corners-West Mesa 345 kV line Four Corners
San Juan-BA 345 kV line
San Juan
San Juan-Ojo 345 kV line
San Juan
McKinley/Yah-Ta-Hey 345/115 kV trans Yah-Ta-Hey
Bisti-Ambrosia 230 kV line
Bisti
Walsenburg -Gladstone 230kV line Walsenburg
Less the following flows:
Belen-Bernardo 115 kV line
Belen
West Mesa-Arroyo 345 kV line
West Mesa
Simultaneous firm: 1849 MW Non-simultaneous: 1970 MW
Critical Four Corners-West Mesa or San Juan-BA 345 kV lines.
Disturbance
that limits the
transfer
capability:
When: The rating was approved by letter dated May 5, 2006.
System
Conditions:
Study Criteria:
Remedial
Actions
Required:
Formal
Operating
Procedure:
The operating transfer limit on Path 48 uses independent real-time nomogram
equations that are incorporated in PNM’s Energy Management System. These
nomogram equations utilize metered real-time system conditions (e.g.,
real/reactive power flows, status of shunt capacitors/reactors, etc.) to
determine the Path 48 limits on a one-minute basis. The nomogram equation
variables included in the Path 48 calculations are therefore dependent upon
system conditions and take into account seasonal and time-of-day variations.
Local New Mexico criteria include pre-disturbance voltage levels between
0.95 and 1.05 p.u., post transient voltage deviation no greater than 6% in
northern New Mexico and 7% in southern New Mexico, or not less than a 5%
voltage stability margin. PNM operates Path 48 based on the lower of the
voltage or thermal limits.
Post-PST New Mexico Transmission Operating Procedure, effective June 18,
1999.
PART VI Item 1-134