The 500-kV Tehachapi Renewable Transmission project in Southern California will deliver renewable energy from Kern County, south through Los Angeles County and then east to the city of Ontario in San Bernardino County, a distance of more than 170 miles. The project, which replaced many of Southern California Edison’s existing 220-kV lines with 500 kV, was all overhead except for 3.7 miles of the line passing through the city of Chino Hills. While that portion represented only 1.5% of the total project, it created unprecedented engineering and construction challenges.
Although this project included just one circuit with two cross-linked polyethylene cables per phase initially, the final build-out can accommodate two circuits with three cables per phase for each circuit, or a total of 18 cables. SCE enlisted Black & Veatch as the engineer of record to handle detailed design, procurement and construction support to resolve the daunting electrical, mechanical and civil engineering challenges this project presented. Throughout the engineering, procurement and construction process, the SCE/Black & Veatch team worked closely and collaboratively with the various stakeholders, including Power Delivery Consultants and MPR Associates, as each new project decision arose.
Following are project photos of the process, originally appearing in "Engineering a 500-kV Underground System" in the May 2017 issue of T&D World.