Thermal Grout, HDD Make 6,200-Foot Electrical Transmission Installation Possible

By Jeff Griffin, Senior Editor | December 2012, Vol. 67 No. 12

“HDPE fusion occurred in one location with the conduits extended in length until complete,” Olson said. “Each HDPE conduit was initially pulled along rollers until the fusion process was complete. Once all conduits had been fused to the overall length, the conduits were removed from the rollers and placed on the ground for the preliminary hydro test. Once the test was performed with successful results, the water from each conduit was purged by propelling a foam pig through each conduit with air pressure.”

Once all conduits were dry, they were placed back onto the rollers and bundled for pulling into the 36-inch steel casing. Bundling of the conduits with 2-inch wide, 0.44-inch thick stainless steel banding spaced at eight foot intervals was applied while the pipe was on rollers immediately prior to pullback.

FOR MORE INFO:
Southeast Directional Drilling, (877) 300-2440, www.southeastdrilling.com
Constellation Group LLC, (410) 484 0672; www.cgllc.us
Waldemar S. Nelson & Company, (281) 999-1989, www.wsnelson.com
M&M Pipeline Services/Energy Services South, (662) 258-7101, www.mmpipeline.com
American Augers, (800) 324-4930, www.americanaugers.com


Thermal Grout Key Element In Project

Most power transmission lines are overhead because the heat they generate can cause multiple problems if they are placed underground.

However, advances in cable design and manufacturing, the use of plastics for insulation, and other factors have made underground placement of high-voltage transmission lines a viable option in many situations.

Thermal grout is used to transmit heat from underground electrical cables into the surrounding soil or rock, said Guy Dickes, president, Constellation Group LLC, who over the past five years has been responsible for planning and executing grouting for major underground power transmission projects, including the Wolf Bay underwater crossing.

The right thermal grout mix correctly applied is a critical element in constructing segments of underground power transmission lines.