Installing Transmission Line in Mountainous Terrain

Project Scope:

EPC of a 138/69/12kV substation and 138kV overhead and underground transmission line

Project Type:

Utility Substations

Transmission Lines

Location:
California
Year Completed:
2015

A California utility company needed to replace a 60-year-old substation and install 14 miles of transmission line. This project was crucial to providing the local area with reliable power, increasing renewable energy and meeting anticipated power grid needs. The utility had worked with Beta on previous projects and selected us for this project because of our proven ability to help them meet their goals.

The biggest challenge of the project was the transmission line. We installed seven miles of underground line and seven miles of overhead line. In one environmentally sensitive area, we completed 550 feet of horizontal directional drilling of a 42" diameter sleeve to depths of 40 feet below grade. The project also involved several jack-and-bore drilling operations to take the transmission line beneath multiple environmentally sensitive areas and under a bridge in one location. Each day we had to cover the bore pits after construction so both lanes of traffic could be reopened, and we used engineered shoring to support the traffic plates. Where a portion of the overhead transmission line passed through a mountainous area with limited accessibility, we used a helicopter sky crane to install one of the overhead structures. Many of the locations required special tools and equipment for rock drilling.

This project was vital to the utility and their energy goals. Through collaboration, the utility and Beta were able to overcome many barriers and complete the project on time.

Detailed Scope of Work

• Environmental mitigation work with customer and regulatory agencies

• Approximately 7 miles of underground transmission line

• Jack-and-bore drilling operations

• Helicopter sky crane operations

• Approximately 7 miles of overhead transmission line

• Traffic control

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