Preventing damage to the sensitive optical fibers within OPGW during stringing is paramount. Unlike conventional conductors, OPGW's primary vulnerability is its optical core. The most critical factors to control are:

• 1. Pulling Tension (Tensile Stress):

  • Control: The pulling tension applied to the OPGW must never exceed its Maximum Allowable Pulling Tension (MAPT). Exceeding MAPT can stretch the metallic strands, which in turn can induce micro-bends or macro-bends in the optical fibers, leading to increased optical attenuation (signal loss) or even fiber breakage.

  • Solution: Our hydraulic pullers and tensioners are equipped with precision digital dynamometers (load cells) and automatic tension control systems. These systems provide real-time tension readouts and can be pre-set to automatically slow down or stop the operation if tension approaches or exceeds the OPGW's MAPT. This ensures the fibers remain unstressed.

• 2. Minimum Bending Radius (Bending Stress):

  • Control: OPGW cables have a strict minimum bending radius (MBR) for both static (installed) and dynamic (during stringing) conditions. Bending the cable too sharply will cause severe macro-bending losses or permanent damage to the fibers. Dynamic MBR during stringing is typically much larger than the static MBR.

  • Solution: We provide large-diameter OPGW-specific stringing blocks (pulleys) and sheaves that ensure the OPGW is never bent beyond its dynamic MBR. These blocks feature wide, smooth grooves lined with protective materials (e.g., neoprene, polyurethane) to distribute pressure evenly and prevent kinking or crushing.

• 3. Torsional Forces (Twisting):

  • Control: Twisting the OPGW cable during stringing can cause the optical fibers inside to twist or even buckle, leading to significant signal loss or fiber damage. This is especially critical for OPGW with a central optical tube design.

  • Solution: The use of high-quality, non-rotating pulling ropes (e.g., braided steel or synthetic ropes) and robust anti-twisting swivels between the pulling grip and the pulling rope is essential. These devices prevent torque from being transferred from the pulling system to the OPGW itself.

• 4. Abrasion and Crushing (External Mechanical Damage):

  • Control: Any rubbing, scuffing, or crushing of the OPGW's outer metallic layers can compromise its structural integrity and potentially damage the internal optical unit. This includes contact with tower steel, ground, or other obstacles.

  • Solution: Beyond the specialized stringing blocks, proper site preparation, ensuring clear pathways, using line guards on cross-arms, and meticulous handling are crucial. Our equipment is designed to facilitate smooth, contact-free stringing.

• 5. Stringing Speed:

  • Control: While efficiency is important, excessively high stringing speeds can lead to dynamic over-tensioning, increased friction, and greater risk of accidental damage.

  • Solution: Our tensioners and pullers allow for precise control over stringing speed, enabling operators to maintain a slow, steady pace, especially around critical points like angle towers or mid-span obstructions.

• 6. Communication and Supervision:

  • Control: Clear, continuous communication between the puller operator, tensioner operator, and ground/tower crews is vital to respond immediately to any issues (e.g., snagging, abnormal tension spikes).

  • Solution: Implementing robust two-way radio or headset communication systems across the entire stringing span. Continuous supervision by experienced personnel.

By utilizing our precisely engineered OPGW stringing equipment and adhering to these critical control factors, our clients can ensure successful, damage-free, and high-performance OPGW installations.