Transmission Line Structures

Shield Wire:
Protects the line from lightning strike to prevent power outages.
Prevents the electricity from short-circuiting from wire to structure.
Carries electricity
Dedicated Metallic Return:
Overhead conductors that ensure any imbalance or return current flow on the HVDC system is not flowing through the earth.

There are many different types of transmission structures used to deliver power.  Clean Line Energy is evaluating the use of steel lattice and steel monopole DC transmission structures to move large amounts of renewable power over long distances to market.

A typical steel monopole transmission structure requires around 35,000 – 40,000 pounds of steel per structure and a typical steel lattice transmission structure requires an average of 32,000 pounds of steel per structure.

The images below show average specifications for a typical steel monopole, typical steel lattice mast, and a typical steel lattice transmission structure.