WSP02437

• File Number: 8220.100.50
• Description: CRSP - Power Issues
• Basin: Colorado Mainstem
• Date: 1/1/1982
• Author: West. Sys. Coord. Co
• Title: Western Systems Coordinating Council Ten-Year Coordinated Plan Summary 1982 - 1991
• Water Supply Pro - Doc Type: Publication

The electric utility industry continues to face economic
uncertainties, regulatory delays, environmental challenges, and other
factors which affect system planning and operation, and therefore
coordination and mutual support among the WSCC Member Systems must be
maintained to promote the reliability of the interconnected bulk power
system. Continued delays in obtaining the necessary approvals for
construction of planned transmission facilities will result in the need to
operate the existing transmission system closer to its maximum capability,
thus utilizing the transmission margins that should be available in the
network to provide for contingency conditions. As a result, the region's

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ownership as defined in the legend and anticipated in-service dates of
planned transmission are generally indicated near the facility.

The WSCC network is characterized by a major loop with
transmission ties intersecting the major loop from Sierra Pacific Power
Company to Utah Power and Light Company and to Idaho Power Company. The
map illustrates a 500 kV network overlaying the lower voltage systems in
British Columbia, the Pacific Northwest, California and Arizona.
Development and strengthening of the 500 kV transmission network is
evident within the Pacific Northwest, California, Montana, Idaho and
Arizona. Additional 500 kV development is evident within Alberta, British
Columbia, and New Mexico. Development and strengthening of the 345 kV
transmission network is depicted through Nevada, Utah, Colorado, New
Mexico and Southern Arizona. High voltage DC transmission includes the
existing 800 kV Celilo-Sylmar line (Northwest to California), and the
planned 1000 kV Celilo-Liberty (Northwest to Arizona) and Intermountain-
Adelanto lines (Utah to California). New interconnections between
Southern California and Mexico, between WSCC and Mid-Continent Area Power
Pool (in Montana), and between WSCC and Southwest Power Pool (in New
Mexico and Colorado) are planned during the 1980's.

The WSCC interconnected bulk power transmission system continues
to be characterized by long transmission lines connecting major load and
resource areas. The planned transmission additions in the WSCC region
through 1991 reflect a continuing interest in the development and
strengthening of interconnections to maintain system reliability, increase
the capability for economy transfers and enable diversity exchange of
power between areas with different seasonal peak load requirements.
Examples of this development include the tentative third Northwest-
California 500 kV AC line and Northwest-Arizona 1000 kV DC line. In
effect the WSCC system is being developed to insure the efficient and
economical utilization of resources and at the same time insure adequacy,
reliability and environmental compatibility.

Figures 14 and 15 illustrate WSCC intra and interregional
transfer capabilities for the 1982 and 1987 summer heavy load conditions,
respectively. The transfer capability limits illustrated in Figures 14
and 15 represent the total capability of the various interconnections of
the existing system and the planned 1987 system. It should be recognized
that the transfer capability of an interconnection is not a single value
as it is dependent upon system conditions. Each transfer capability
depicted in Figures 14 and 15 has been determined for a specific system
condition.