Multiple Transmission Projects

Location: Texas

Client: Lower Colorado River Authority

Zorn to McCarty Lane

Burns & McDonnell designed a 9-mile 138-kV line requiring reconductoring of one circuit to 1033.5 Merrimack ACSS/TW. Burns & McDonnell provided structural analysis of the existing lattice towers, where necessary modified the structures to provide additional capacity and clearance improvements.

McNeil to Round Rock

Burns & McDonnell designed an 8-mile 138-kV line rebuild requiring new monopole construction for bundled, 795 kcmil Drake. Burns & McDonnell designed the line with both steel and concrete poles.

Macedonia to Hockley

Burns & McDonnell designed a new 13.5-mile 138-kV line. The line consists of 3 miles of double circuit line along an existing San Bernard Electric Cooperative right-of-way, 6 miles of single circuit paralleling a CenterPoint Energy 345-kV line, and 4.5 miles of low impact single circuit construction meandering through farmland and tying in to a CenterPoint Energy 138-kV line. All construction utilizes both steel and concrete monopoles.

Bellville South to Peters

A 9-mile existing transmission line circuit from their Bellville South substation to the Peters substation. The circuit was installed initially using 795 kcmil ACSR Condor and 795 ACSR. Burns & McDonnell designed an upgrade to the conductor on the transmission line using 959 ACSS/TW. The rebuild required some structural modifications to existing lattice towers and steel poles.

Kendall to Miller Creek

A 40.4-mile existing 138-kV transmission line that connects the Kendall substation to the Miller Creek substation. The line was single circuit with Linnet 336 kcmil ACSR conductor. The line was being operated at 82 MVA. Burns & McDonnell evaluated and redesigned the line to a re-rated 128 MVA.

Buchanan-Graphite Mine-Lampasas

A 27.5-mile 138-kV transmission line from Buchanan to Graphite Mine to Lampasas. The existing line was single circuit with 336 ACSR conductor and wood H-frame structures. Burns & McDonnell designed an upgrading to the conductor on the transmission line to 795 ACSR Drake. The conductor upgrade increases the power transfer capacity from 128-MVA to 220-MVA.

Hill Country Cut In

A 2.8-4.2 mile 138-kV double-circuit-capable transmission line between the existing Cico-Helotes 138-kV line and a new distribution substation (Hill Country Substation) that will improve the reliability of electric service to customers served by Bandera Electric Cooperative and the City of Boerne. Without this project, load growth and contingencies in this area will continue to threaten the integrity of the electric system and its ability to provide stable and acceptable service to the growing loads in the Kendall County area. Burns & McDonnell evaluated concrete and steel monopoles and steel lattice towers. The amount of right-of-way required varies for each type of structure and depends on structure width, phase spacing, span length and wind-induced conductor movement.

Kendall to Cagnon

Rebuilding 25 miles of existing, double-circuit 138 kV transmission line for operation as a double-circuit 345/138 kilovolt (kV) transmission line from LCRA’s Kendall Substation to the Bexar County line to interconnect with a 345 kV transmission line being constructed by San Antonio’s City Public Service Board (CPSB). The finished circuit will be approximately 45 miles in length and extend from LCRA’s Kendall Substation to CPSB’s Cagnon Road Substation. CPS will permit, design, and construct the line from the Kendall/Bexar County line to the CPS Cagnon Road substation. The line will be operated as a double-circuit, 345/138 kV electric transmission line capable of being upgraded to a double-circuit, 345-kV transmission line supporting 6x2-1590 kcmil 54/19 ACSR Falcon conductors with one 3/8-inch 7-strand extra high-strength steel shield wire and one Optical overhead ground wire. The 345-kV circuit will be rated for operation at 2,690 amperes, yielding a nominal 1,600 megavolt-amperes (MVA). The 138-kV transmission line will be rated for operation at 920 amperes, yielding a nominal 220 mega-Volt-amperes (MVA) capacity.

Comfort to Raymond Barker

Upgrade and reconductoring from 69-kV to 138-kV. The upgrade will utilize 795 ACSR Drake conductor and OPGW fiber optic shield wire. This line is located in Kendall and Kerr County. With the exception of the tangent structures between Cypress Creek and Raymond Barker substations, all structures will be replaced. The circuit will be rerouted into the Comfort Substation. This 10-mile circuit will be operated as a single circuit, 138-kV electric transmission line utilizing 3x1-795 ACSR Drake conductors with one OPGW fiber optic shield wire, and will be rated for operations at 920 amperes, yielding a nominal 220 mega-Volt- amperes (MVA) capacity. Burns & McDonnell provided the following services:

  • Finalizing plan and profile sheets in accordance with LCRA standards
  • Hardware and assembly drawings
  • Sag and tension charts
  • Finalizing PLS-CADD model of transmission line
  • Developing construction bid specification and construction support

Clear Springs

Transmission facilities for the T119 Comal to Freiheit and the T264 Freiheit to Seguin transmission lines required rebuild to support the Clear Springs 138/345 auto-transformer upgrade project. Burns & McDonnell designed the 138kV transmission line from Freiheit to Seguin for the Clear Springs project. All structures were replaced except for the double-circuit located outside the Geronimo substation. This structure was previously modeled in PLS-Tower and will be evaluated for capacity by the Lower Colorado River Authority. The project proceeded with the existing transmission line alignment and with a new 180-foot right-of-way acquired for the tap into Clear Springs Substation (0.4-miles).