Wirtz to Flatrock to Paleface, Transmission Line Upgrades

PEC is upgrading the existing 17.4 mile electric transmission line running from Travis County to Burnet County which connects Wirtz, Flatrock, and Paleface substations. The upgrade began in 2018 when PEC replaced about 50% of the existing wood poles with steel monopole structures. This phase of the project will replace the remaining wood pole structures and install larger conductors which will help meet the area’s growing demand for electrical power, improve system reliability, and reduce maintenance costs.

Engineering is scheduled to be completed in August 2021. Construction is scheduled to start in September 2021 and be complete May 2022.

The transmission line begins at Paleface substation, then heads northwest for approximately 8.1 miles to Flatrock substation. The line then continues northwest for approximately 4.1 miles where it crosses the corner of Starcke substation. The line then continues west for an additional 5.2 miles to Wirtz substation.

The rebuild will take place within an area currently occupied by transmission line to help minimize the impact to landowners adjacent to the existing line. Existing infrastructure including wood pole structures will be replaced with steel monopoles and bundled 795 kcmil ACSR (wire) that can carry more power and be operated at the same voltage. The existing shield wire is also being replaced with an optical ground wire for improved relay coordination and supervisory control of substations.

Questions and Answers

What is PEC doing to the transmission line?

PEC will rebuild and upgrade the existing wood-pole 138 kV transmission line that connects the existing Wirtz, Flatrock, and Paleface substations in Burnet and Travis County areas.

Why is this project needed?

The project is needed to increase the capacity of the transmission system in order to meet the area’s growing demand for electrical power, improve reliability, and reduce operating and maintenance costs.

What will be the impact of the project for landowners along the route and the community?

The primary impact will be during construction where structures are located. PEC crews and contractors will utilize heavy machinery and equipment to dig holes, remove existing wood structures, install new steel pole structures, and replace existing wires. The rebuild will take place within the areas currently occupied by the existing transmission lines to help minimize the impact to adjacent landowners.

How much will you have to be on my property?

In January and February, a geotechnical consultant will send a drill rig to take soil boring at nine points along the line. These soil borings take approximately one half of one day each. Landowners with land being accessed for the soil borings will be notified.

The main construction of the line will begin in August of 2021. The first step of construction prepares the right-of-way so that large equipment can access the transmission structures that need to be replaced. The second step of construction will consist of removing the old structures, setting the new structures, and replacing the wire. The second step of construction will require contractors to be at the structures for three to five days per structure while they are being set and is followed after several weeks by another day to secure the new conductor.

Construction crews use the right-of-way to access structures on your property and to access structures located down the line on neighboring properties.

At the end of construction, PEC will grade areas that have been disturbed by construction activity and plant seed to restore the right of way. Soil erosion devices will be installed and maintained where necessary during construction. After the soil has been re-vegetated sufficiently, the soil erosion devices will be removed.

What will the new structures look like?

The structures are galvanized tubular steel poles that are capable of supporting a single circuit and a shield wire. Each circuit is comprised of three sets of conductors, also referred to as phases. Each phase will contain two conductors. Structures needed at the large angles in transmission line will be placed on concrete foundations. The tangent structures needed to support the wires between the large angle structures will be placed directly in the ground with a concrete back fill or with a gravel/base material

How large will the structures be?

Structures and line are still being designed; however, large angle structures are expected to be between 6 and 8 feet in diameter at the base. Tangent structures are expected to be between 3 and 5 feet in diameter at the base. The height of the structures is expected to be between 75 and 95 feet above ground.