In power systems, overhead transmission lines are highly vulnerable to natural forces—particularly strong winds, which are considered a major “natural enemy.” To mitigate wind-related risks, designers incorporate comprehensive wind-resistant features into transmission line structures.
What Threats Do Strong Winds Pose to Transmission Lines?
Wind Deflection Tripping
This is the most common form of wind-induced failure. When wind causes conductors to sway, the reduced electrical clearance may lead to flashover and line tripping.
Fitting Damage and Mechanical Overload
Under light wind (breeze), long-term oscillations can cause wear and tear on fittings. Under strong winds, insulator strings and hardware may be subjected to forces beyond their design limits, potentially resulting in breakage or the dropping of components.
Ground Wire Fatigue and Breakage
Both breeze vibration and high winds can cause fatigue damage to ground wires. Excessive tension may lead to strand breakage or flashover events that burn or damage the wire.
Structural Failure of Towers
When wind loads exceed the structural design capacity of transmission towers, it may cause deformation or even complete collapse. This is the most severe and catastrophic consequence of wind-related threats.
How to Prevent Wind-Related Damage?
Determine Design Wind Speed Reasonably
This is the foundation of wind-resilient design. Accurate meteorological data should be collected along the planned transmission route. Based on regional wind maps and historical operation data, a reasonable design wind speed should be selected according to a defined recurrence period.
Use V-Shaped Insulator Strings on Suspension Towers
On straight-line towers, V-shaped insulator strings form a triangular structure with the crossarm, which stabilizes the conductors. This design helps prevent flashover and tripping caused by wind-induced conductor swing, which is common with I-type strings.
Install Reinforced Windproof Composite Insulators on Tension Towers
Unlike traditional “hinged” installation methods, windproof composite insulators use a “cantilever” or rigid support approach. This converts the jumper from a dynamic element into a static one, significantly reducing swinging and ensuring electrical clearance is maintained from the jumper to the tower body.
Adopt Low Wind-Pressure Conductors
Low drag conductors can reduce wind pressure and drag coefficients by up to 30% compared to conventional wires when wind speeds are between 30–60 m/s. This not only lessens the wind-induced deflection angle but also decreases the load on transmission towers.
Install Anti-Vibration Dampers
Breeze vibration occurs when steady, low-speed winds (0.5–10 m/s) generate alternating vortices behind the conductor, producing oscillations. If the frequency of these pulses matches the natural frequency of the conductor, sustained up-and-down vibrations can lead to fatigue failure. Anti-vibration dampers absorb this mechanical energy and reduce vibration amplitude, protecting ground wires and attached hardware.