Path Rating Catalog 2013 - Western Electricity Coordinating Council

81. Centennial
Revised November 2007
Accepted Rating
Existing Rating
Other
Location:
Definition:
Transfer Limit:
Critical
Disturbance
that limits the
transfer
capability:
When:
System
Conditions:
Study Criteria:
Southern Nevada
Sum of flows on the following three 500 kV lines:
Line
Measuring Point
Harry Allen-Crystal 500 kV
Harry Allen
Lenzie-Northwest 500 kV
Northwest
Harry Allen (or future Sunrise tap)-Mead 500 kV Mead
3000 MW (outbound from Harry Allen)
For original definition:
• The Northwest 500/230 kV autotransformer and/or Crystal 500 kV
phase shifters reach their emergency limit during loss of Harry
Allen-Mead 500 kV line
For redefinition:
• Mead-Marketplace 500 kV lines reaches its continuous and
emergency limits during loss of Crystal-McCullough 500 kV line
or Palo Verde-Devers 500 kV line
The path was defined with The Centennial Plan: Western Arizona
Transmission Studies Task Force Report, which was approved by WATS in
April 2004. PCC approved study work in April 2004 and was given a Phase
3 path rating in May 2004.
Redefined in June 2007. Went through the WECC Expedited Review Process
in March through May 2007. Approved by WATS in May 2007. PCC and
TSS approved this redefinition on July 25, 2007. Centennial Project was
completed on April 18, 2007 when KT2A 500/230 kV transformer at
Western’s Mead 500 kV substation was put in service by WALC (Western).
This also signified completion of Phase 3.
The path rating was evaluated during peak summer loading conditions and
light winter loading conditions. In addition, it was also evaluated under
heavy autumn conditions with maximum EOR flows, SCIT imports, and
southern Navajo flows. For rating acceptance, 3000 MW of generation was
modeled at Harry Allen.
Five redefinition sensitivity cases have been considered and compared with
the benchmark cases (based on the approved by WATS for the original
Centennial, EOR and DPV2 Project studies). The cases considered maximum
EOR, WOR and “Mead Hub” (includes Mead-Perkins (Path #63) and Mead –
Marketplace lines) flows.
WECC and Nevada Power Company Reliability Criteria for System Design
Revised November 2007
PART VI Item 1-203