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
Guy Wire:
Supports the structure.

There are many different types of transmission structures used to deliver power. Clean Line Energy is evaluating the use of steel H-frame, monopole, and guyed 3-pole alternating current (AC) transmission structures for its Western Spirit transmission line. The majority of the line will use H-frame structures; monopole structures will be used near river crossings, and guyed three-pole structures may be used when the transmission line changes direction. Whether a “running angle” or “dead end” guyed 3-pole structure is used will depend on the curvature of the turn.

The images below show average specifications for typical steel H-frame, monopole and guyed 3-pole structures.


Typical H-Frame Structure


Typical Monopole Structure