115-kV Underground Transmission

Location: Puerto Rico

Client: Ray Engineers & Associates

Completion Date: 2006

To increase system reliability, PREPA put its 25.4 mile 115-kV overhead transmission loop around San Juan underground.  Project design included 28,700 feet of 2750 kcmil solid dielectric cable, concrete encased ductbank and six trenches crossings totaling 2,800 feet. The project was divided into five phases, Burns & McDonnell assisted in the engineering of Phase I and Phase IV.

Phase I of this project spanned 5.4 miles from Monacillos Substation to Hato Rey Substation. Phase IV spanned 5.9 miles from Bayamon Substation to Monacillos Substation. The system includes a new 115-kV circuit, a future 115-kV tie-in, and a future 38-kV circuit.

Burns & McDonnell worked in conjunction with the turnkey team to provide a seamless and cost effective design through weekly conference calls and periodic design conferences. Engineering services included providing: final routing of ductbank, a complete set of plan and profiles, pulling tension calculations, cross bonding calculations, ductbank design, ampacity calculations and construction support.

  • Technical routing and layout
  • Detailed engineering, including:
    • Pulling calculations
    • Trenchless crossing layout
    • Construction drawings and specifications
  • Construction support