Main stresses on ADSS optical cables

ADSS optical cables are primarily subjected to tensile stress, environmental loads (wind and ice), and electrical field-induced stress, all of which influence their design and long-term performance.

Tensile Stress

Ultimate Tensile Strength (UTS/RTS) is the maximum load the cable can withstand before breaking, determined by the strength of the load-bearing elements such as aramid yarns or spun fibers. The Maximum Allowable Tension (MAT) is typically around 40% of RTS and is used for sag-tension-span calculations, ensuring the cable operates safely under normal conditions without damaging the fibers. Ultimate Operating Tension (UES) allows short-term overloads, generally exceeding 60% of RTS, where fiber strain remains within safe limits to prevent permanent attenuation.

Environmental StressesADSS cables experience wind pressure and ice loading, which add to the mechanical tension along the span. The sag of the cable is influenced by these loads, and proper sag-tension design ensures the cable maintains safe clearance from the ground, conductors, and towers. Long spans, sometimes exceeding 700 meters, require careful consideration of these stresses to prevent fatigue and vibration damage.

Electrical Field-

Induced Stress

Although ADSS cables are all-dielectric and contain no metal, high-voltage electric fields can induce stress through corona effects or electrical corrosion. Cable hanging points are selected to minimize field strength exposure, typically below 25 kV/m for AT-sheathed cables and below 12 kV/m for PE-sheathed cables. This reduces the risk of degradation and mechanical weakening over time.

Fatigue and Long-

Term Stress

Annual average stress (EDS) represents the long-term average tension under normal conditions (no wind, ice, or extreme temperatures), usually 16–25% of RTS. This parameter is critical for evaluating fatigue aging and designing anti-vibration measures to maintain optical performance over the cable's lifetime.

Summary

In practice, ADSS cables are designed to withstand a combination of: Tensile stress from their own weight and installation tensionEnvironmental loads including wind, ice, and temperature variationsElectrical field effects from nearby high-voltage linesFatigue stress over long-term operation Proper selection of cable type, sag-tension design, and installation hardware ensures reliable performance and minimal optical attenuation throughout the cable's service life.