Other Services
Underground Transmission
A leader in the underground transmission industry as well, Wilson’s underground transmission group has installed over 2,100,000 feet of XLPE cable through 345kV, including 756 terminations and 767 splices nationwide. With more underground cable installation experience than virtually any other contractor in the nation, our expertise assures our clients of a superior product installation and quality, on-time performance.
Additionally, our unique cable pulling equipment, specifically fabricated for our purposes, allows us the flexibility and resources to provide the most reliable installation in the field.
In 2000, Wilson's underground transmission group completed one of the largest 230kV XLPE projects in the U.S. at the Los Medanos Energy Center and the Delta Energy Center in Pittsburg, California. From solid dielectric to high pressure, fluid-filled, we have the transmission expertise to tackle even the most complex projects with success. Staying ahead of the competition through safety conscious operations and quality design/build construction services, we have earned our client’s trust, confidence, and repeat business time and time again.
Proven Expertise – From Planning Through Performance
Projects Examples
Sinatra 230kV Loop In Underground Project, NV
Wilson Construction Co. had a little lady luck on its side last summer when Nevada Energy awarded the Sinatra 230kV Loop-In Project located in Las Vegas, NV to Wilson Construction Co. The project consisted of one (1) mile of two (2) double circuit duct banks, eight (8) transmission vaults, 12 each open air and GIS terminations and 36 splices all to be completed under a tight performance schedule. The Sinatra project embodied all of Wilson’s underground transmission capabilities in that it combined not only cable installation and civil construction but splicing of open air terminations on steel poles as well as GIS terminations in a substation.
To meet the project completion dates, the 48 cable pulls were performed non-sequentially, typically in sets of six (6). Among the highlights of the civil work was a 26ft deep excavation to tie the duct banks into existing bore casings under Interstate I-15 and two separate crossings under an 84” transmission water line at a depth of 23ft deep.
South Bay Power Station (OMPPA) Underground Transmission Line Project, CA
This project consisted of the installation of double circuit 230kV transmission line. The project encompasses two segments of the Otay-Mesa Power Loop which is over 10 miles of duct bank equating to over 320,000 lf of cable installation, 210 splices, and 24 terminations. Wilson’s scope included the cable pulling as well as supporting the cable manufacturer’s jointing teams. The cable was manufactured by Silec Cable of France.
Segment five of the project originates in the active SDG&E Old Town Substation and meanders along the famous Pacific Coast Highway through Downtown San Diego where it transitions to overhead south of downtown in the shipyards. Segment 3 originates at a transition structure in National City where it is goes underground through a 3500’ directional drill under the environmentally sensitive Sweetwater Marsh continuing through heavy industrial facilities located in Chula Vista where it finally transitions back to overhead at the South Bay Power Plant.
Kendall Yards 115kV Underground Transmission Line Project, WA
Wilson Construction Company recently installed a 115kV underground transmission cable connecting the College/Walnut Substation to the Post Street Substation for Avista Utilities. The project included installation of the cable, grounding, racking and support structures as well as support of the cable manufacturers jointing teams to install six 115kV splices and six terminations. The new underground line consisted of three underground segments totaling ¾ of a mile.
This project proved to have many challenges unlike the typical underground project. Challenges included installing cable into a substation where the cable terminated on the first floor of an indoor substation where the duct bank ended at the basement wall of the building, one level below the station bays and without cable trays, cable supports or any pre-arranged pulling eye locations to rig to. Wilson Construction crews also faced heavy snow fall and cold temperatures as work begun in early February, 2008 and was completed in March, 2008.
Home Payne Substation to Cathedral Square -- BC Hydro 230kV SCFF Transmission Line, British Columbia
This project involved the installation of nearly six miles of underground 230kV PPLP cable. It was Wilson Construction's first truly international project.
For this project BC Hydro elected to contract directly with the cable manufacturer for both supply and installation of the cable system. Fujikura America, Inc. in turn contracted the cable installation to Wilson Construction. This line was for a major trunk line going from BC Hydro's famous Cathedral Substation east to the Horn Payne Substation. The entire project was located in busy city and residential streets. The project was completed without incident and the owner and Fujikura were both extremely satisfied with the project.
Mississippi River Crossing, 230kV Transmission Line, LA
This extraordinary project consisted of the installation of a 230kV transmission line underneath the Mississippi River. To accomplish the work, Entergy negotiated the bore under separate contract and issued a single RFP to the cable manufacturers for supply and installation of two circuits of 230kV XLPE cable. The RFP also required the supply and installation of a spare cable for each circuit as well.
Wilson Construction was awarded the contract by J-Power Corp./Sumitomo Electric for the installation and termination of eight 230kV cables. The cables were a 2500mm2 segmental CU conductor and utilized individually insulated strands to eliminate the skin effect. The total length of the run was approximately 3,300 feet.
Center Substation 345kV Solid Dielectric Interconnects, TX
This project included the design, procurement, and construction of the underground duct bank, cable system and GIS pits for five each 345kV solid dielectric cable interconnects from the Independent Power Producer plant to the GIS equipment in Deer Park, Texas.
The project consisted of approximately 8000 ft. of 630mm2 345kV XLPE copper cable, 15 GIS terminators and 15 open-air terminators. Project requirements included designing a GIS pit to incorporate five circuits, with cables to be installed at different times over a two-year period. The cables installed first were to be energized before the next cables would be pulled, creating significant safety issues for the field installation. We designed the GIS cable pit so that the cable would be installed in conduits all the way to the GIS terminator. In this way the GIS pit was dug open one time, conduits were installed and the pit closed. With the conduits already installed for all five circuits, pulling the remaining cables became a much easier and safer job.
First 345kV XLPE underground transmission contract in the U.S. Mystic Station 345kV & 115kV and Fore River Station 115kV Projects, MA
This project involved the high voltage interconnect for two power plants in the
The Fore River Station is a 800MW plant and included three circuits of 1400mm2 CU 115kV cable with two conductors per phase. The plant end of these cables terminated into GIS equipment while the three utility termination points were open air.
Los Medanos Energy Center/Delta Energy Center OSBL Electrical Underground & Overhead Transmission Lines, CA
One of the largest 230kV projects in the U.S., this fast-track EPC contract included the 115kV and 230kV transmission lines interconnect for the Los Medanos Energy Center (LMEC) and Delta Energy Center (DEC). Both the LMEC (500 MW) and the DEC (880MW) plants are combined cycle cogeneration plants. The LMEC interconnect involved approximately 5000 feet of overhead and 5000 feet of underground 115kV transmission line. This two-circuit line included overhead bundled 2300kCMIL and underground 3000kCMIL with two conductors per phase. The underground portion was completed with two splice points in the circuit and approximately 60,000 feet of solid dielectric cable. The base contract included only the underground portion of the DEC 230kV interconnect and utilized 2500kCMIL conductor with two circuits and two conductors per phase. The DEC line required five splice points and involved approximately 120,000 feet of solid dielectric cable.
