Transmission structures are generally broken down

into three types; Tangent, Angle and Dead-End.

Tangent

• More

economical due to

lighter loads

• Generally no

longitudinal loads

on the structure

Angle

•Used when

transmission route

changes direction

•Used from anywhere

less than a 5 degree

angle to a 90 degree

angle

•Experience greater

transverse loads

caused by the

transverse component

of the wire tension

Dead-End

• As name applies, dead-

ends are designed to

take the full component

of every wires’ tension

•Does not necessarily

mean end of

transmission line

There are different configurations whether tangent,

angle or dead-end structures are used, and may

have phases in:

•Horizontal configurations- provides the lowest

profile

•Vertical configurations- requires the minimum

width right-of-way

•Delta configurations- can reduce electrical line

losses by using horizontal and vertical distances to

maintain phase clearances

Self-supporting structures do not

use guys. They are not tied to the

ground or any other structure in a

way that offers additional support.

They are better for restrictions to

right-of-ways and tend to have

loads small enough to not warrant

guys.

Guying of structures is used to support the structure to allow for a

more economical design in both the steel structure and the

foundation. Guying of a structure will reduce bending and

deflection. The downside of guying, is that it requires more

right-of-way.

Guyed

Considerations for guyed

structures:

•Line voltage

•Electric air gap clearance

requirements

•Ground clearance requirements

•Insulation requirements

•Structural loading

•Right-of-way requirements

•Aesthetic design criteria

•Number of circuits to be

supported

•Electric & magnetic field limits Two Single-Circuit Guyed

Angle Structures

Angle (All 3 can be guyed)

H-Frame Mono Pole 3-Pole

Dead-End

H-Frame Mono Pole 3-Pole A-Frame

Tangent (Generally not guyed)

Mono Pole H-Frame

Arms No Arms

•Either base-plated with

anchor bolts or directly

embedded

•Easy installation

•Can be used as tangent,

angle pole or dead-end

structure

•Can be used for small

right-of-ways

Tangent, mono pole with arms, delta

configuration, non-guyed structure

Self-Supporting Mono Pole

•Made up of at least two

poles

•Connected with one or

more crossarms

•Sometimes guyed when

used as an angle structure

to lessen uplift, bending,

deflection

•Sometimes guyed

longitudinally when used

as dead-end structures

•Use more space in right-

of-way Tangent H-Frame, Weathering Steel

H-Frame

•Made up of three poles

•Each pole carries one

phase

•Used for large divergent

angles or as dead-ends

•Requires more right-of-

way space

•Can be self-supporting,

but are usually guyed to

lessen bending and

deflection

Double-Circuit, 3-Pole

Angle Structure

3-Pole Structure

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Call (318) 448-0274

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