Dampers in transmission lines prevent oscillations in overhead transmission lines. As a result of laminar wind, overhead transmission lines will experience vibrations and oscillations. Then they can cause damage to the conductor, single parts, or the pole. Damping systems in overhead transmission lines will be required to reduce these vibrations and oscillations to an uncritical dimension.
The Cause of Wire Viberation
When the lightning protection wire of the wire is subjected to a uniform and low wind speed. That is to say, a wind speed of 0.4-8m/s. An eddy current will be generated on the leeward side of the wire. Under the action of the force, the wire periodically oscillates in the vertical direction in the entire span. We call this the vibration of the wire.
Harzard of Wire Viberation
Long-term vibration of the wire will cause additional mechanical stress to the wire material. It may cause the wire fatigue and break for a long time.
The vibration of the wire is a great threat to the safe operation of the line. The viberation can cause the wire to break. It also can make the steel feet of the insulator to loosen and fall off. Finally, damage the tower.
The structure of the anti-viberation Damper
It is made of two cast iron hammer heads. It consists of a short steel strand and a clamping plate fixed on the steel strand.
Some Types of Anti-Viberation Dampers
Type FD Anti-Viberation Damper
Type FDZ Anti-Viberation Damper
The Principles of Anti-Viberation Damper
When the overhead line vibrates, the anti-vibration hammer installed on the overhead line moves up and down accordingly. The inertia of the hammer head makes the steel strand connecting the hammer head bend up and down continuously. Therefore, friction between strands and molecules within the material consumes energy.
As the bending of the steel strand increases up and down, the vibereation consume more energy. Then the energy consumption of the vibration transmitted by the wind to the overhead line becomes large. Thus, the large-scale vibration cannot be generated.
Since the residual vibration energy is reduced, the amplitude of the overhead line also become smaller.
The anti-vibration hammer protects the overhead line by consuming the ability of the overhead line to vibrate to control the amplitude.
The Installation Distance and Number
Installation Distance
The installation distance of the anti-viberation damper is very important. It is usually proposed by design. They can calculate the installation distance according to the maximum half-wave length and the minimum half-wave length.
How Many will be Installed
The selection of the number of anti-vibration hammers is related to the diameter of the overhead line, the span and the energy of the wind acting on the overhead line. It is usually proposed by design.
| Numbers of viberation damper | 1 | 2 | 3 |
| Diameter of overhead lines(mm) | Range of distance (m) | ||
| d<12 | ≤300 | >300～600 | >600～900 |
| 12<d≤ 22 | ≤350 | >350～700 | >700～1000 |
| 22<d≤ 37.1 | ≤450 | >450～800 | > 800～1200 |
Prepare Before Installation
Five steps to do before installation
- Wear uniform
- Tool preparation
- Material check
- Staff team
- “Triple check” before start
Operation Stage
Before climbing the pole, you shoud
- Check the rod root cable
- Check pole climbing tools, seat belts and fall arrest gear
- Check the sturdy of the cross-arm connection and if it is corroded before placing the cross-arm
- Proficient and accurate in climbing action
Procedure of installion
How to climb
- Use ladders
- Ride on the overhead line
How to mark?
According to the installation distance provided by the design, measure it out with a steel tape measure and mark it with a marker.
There are two ways to mark.
From the center of the clip hanging point to the center of the anti-vibration hammer hanging point, marked as h.
From the cable outlet of the cable clamp to the center of the anti-vibration hammer hanging point, marked as h1.
Three Points Wrapping Aluminum Tape
The winding direction is the same as the wire winding direction
The aluminum-clad tape at both ends should be turned back
The aluminum wrapping tape at both ends should not exceed 10mm
Four Points for Install Anti-Viberation Damper
Same bolt through
Bolts should be tightened
Damper naturally perpendicular to the ground
Damper parallel to the wire
After installation
Check the safety distance
Check if there are belongings on the tower
Lifting tools
Climbing down the pole correctly and safely
