Grand Isle gets 13 km underground transmission line
USA, Louisiana, Grand Isle: Entergy Louisiana recently completed the longest underground project in company history, increasing the resilience of the electric system.
The project is aimed to improve day-to-day reliability and help the company and our communities recover more quickly following major storms.
Crews undergrounded approximately 13 km (8 mi) of distribution powerlines along Louisiana Highway 1 from Leeville to Grand Isle. This is one of two main lines serving the area, with the other being a hardened overhead line that boasts Class 1 poles placed into steel caissons (metal pipes) and backfilled with rock to create a stronger foundation to offset challenging soil conditions.
While the underground line brings significant benefits in terms of combatting high winds, the overhead line, also along LA 1, was built to withstand winds of up to 150 mph and provides the company an option for quickly repairing equipment and bringing power back to the area if both feeds were to be affected.
“The work we have done throughout our coastal communities is the very definition of adding resilience to the electric system,” said John Hawkins, vice president of reliability for Entergy in Louisiana. “It is not necessarily a matter of whether the lights go out, but a matter of how quickly we can get them back on, and that is what ongoing grid resilience.
The company also relocated some portions of the electric system that had to be rebuilt following Hurricane Ida from hard-to-access areas in the marsh to more accessible areas, another tactic aimed at reducing the time it takes to perform work and safely restore power.