115-kV Underground Transmission

To increase system reliability, PREPA is putting 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, six trenches crossings totaling 2800 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 spans 5.4 miles from Monacillos Substation to Hato Rey Substation and Phase IV spans 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 & Layout
• Detailed Engineering, including providing the following:
  • Pulling Calculations
  • Trenchless Crossing Layout
  • Construction Drawings and Specifications
• Construction Support