Types of Electric Transmission Tower

Tower Types Power Transmission

Transmission towers and their overhead power lines are often considered a form of visual pollution. An Electrical Transmission tower is a tall structure, usually, a steel lattice tower used to support an overhead power line.

There are four major categories of transmission towers:

• suspension tower, 
• terminal tower, 
• tension tower, and 
• transposition tower. 

Some transmission towers combine these essential functions. They are used in high-voltage AC and DC systems and come in a wide variety of shapes and sizes.

Towe Types based on Tower materials

1. WOODEN POLES

2. RCC POLES

3. STEEL TUBULAR POLES

4. STEEL TOWERS

Towe Types based on line diversion

Type A Tower 

(Tangent Tower with suspension string)

Used on straight runs and up to 2° line diversion.

Type B Tower 

(Small Angle Tower with tension string)

Used for line deviation from 2° to 15°.

Type C Tower 

(Medium Angle Tower with tension string ).

Used for line deviation from 15° to 30°.

Type D Tower 

(Large angle tower with tension string)

Used for line deviation from 30° to 60°.

Type E Tower 

(Dead End Tower with tension string)

Used for line termination & starting.

Special tower-

Suspension Tower (Span ≈ 1000 m) 

Used for River crossing, Mountain crossing, etc.

Transposition Tower

Used for transposition of tower

Towe Types based on line current

1. HVDC Tower
2. HVAC Tower

Towers carrying AC circuits and DC electrode lines exist in a section of the powerline between Adolph Static Inverter Plant and Brookston the pylons have the electrode line of HVDC Square Butte.

The overhead section of the electrode line of Pacific DC  Intertie from Sylmar Converter Station to the grounding electrode in the Pacific Ocean near Will Rogers State  Beach is also installed on AC pylons.