Loose Tube Layer Stranded Non-metallic Reinforced Core Non-armored Optical Cable

With its excellent comprehensive performance, GYHTY optical cable has become a core infrastructure for modern communication network construction. With continuous innovations in materials science and communication technology, GYHTY optical cable will play a more critical role in smart grids, rail transit, industrial Internet and other fields, driving the development of communication networks towards high-speed, intelligent and ubiquitous directions.

Product Description

Colored optical fibers are placed into a loose tube made of high modulus material, which is then filled with thixotropic water-blocking gel. The center of the cable core contains a glass fiber reinforced plastic(FRP). The loose tube(and filling rope)is twisted around the central reinforcing core to form a circular cable core. Gaps in the cable core are filled with water-blocking gel, and then extruded with a polyethylene inner sheath. This is followed by an outer sheath made of aramid yarn, extruded with polyethylene to complete the cable.

Product Features

The material of the loose tube itself has good resistance to hydrolysis and high strength.

◆Possesses good mechanical performance and temperature characteristics.

◆Aramid reinforcing elements enhance the cable's tensile strength.

◆Filled with thixotropic gel inside the tube, providing crucial sealing protection to the optical fibers.

◆PE sheath has excellent resistance to ultraviolet radiation.

◆Single non-metallic central reinforcing core.

Application: Ducts, Aerial, Direct Burial

1. Overview

2. Core Structural Design and Material Characteristics

2.1 Central Strength Member System

• Material Selection: Glass Fiber Reinforced Plastic (FRP) is used as the central strength member, with an elastic modulus of over 100 GPa. It combines the rigidity of metallic materials with the insulation properties of non-metallic materials.

• Mechanical Properties: The tensile strength of a single FRP rod is ≥1200 MPa, providing basic tensile resistance for the cable while avoiding the risk of induced current in high-electricity environments.

• Structural Optimization: The surface of the FRP rod is specially treated to form a tight stranded structure with surrounding loose tubes, ensuring uniform stress distribution and reducing micro-bending losses in the optical fibers.

2.2 Loose Tube and Fiber Protection System

• Loose Tube Material: Polybutylene Terephthalate (PBT) is used, with a glass transition temperature of ≥220°C, maintaining stable mechanical properties in the temperature range of -40°C to +70°C.

• Fiber Protection Mechanism:

• Special ointment (dropping point ≥120°C) is filled inside the tube, with a dynamic viscosity of 5000-8000 mPa·s at 25°C, effectively buffering external mechanical shocks.

• The fiber excess length is controlled at 0.5%-0.8%, achieved through precise stranding processes, ensuring that the fiber strain ≤0.05% under temperature changes.

2.3 Cable Core and Sheath Reinforcement System

• Cable Core Structure:

• Loose tubes and filling ropes are stranded around the central strength member in an SZ stranding manner, with a stranding pitch of 20-30 times the cable diameter, forming a compact circular structure.

• The gaps in the cable core are filled with water-blocking yarn (water absorption capacity ≥20 times its own weight), with a longitudinal water-blocking rate ≤0.1 mL/m, meeting the requirements of IEC 60794-1 standard.

• Sheath Design:

• The inner sheath is made of High-Density Polyethylene (HDPE) with a thickness of ≥1.5 mm and an environmental stress cracking resistance time (ESCR) of ≥1000 hours.

• An aramid yarn layer is added to the outer sheath. The aramid has a density of 1.44 g/cm³ and a breaking strength of ≥2800 MPa, increasing the short-term tensile capacity of the cable to over 1500 N.

3. Key Performance Parameters Analysis

3.1 Optical Transmission Performance

• Attenuation Characteristics:

• Single-mode fiber (G.652D): Attenuation ≤0.36 dB/km at 1310 nm wavelength and ≤0.22 dB/km at 1550 nm wavelength.

• Multi-mode fiber (50/125 μm): Attenuation ≤3.0 dB/km at 850 nm wavelength and ≤1.0 dB/km at 1300 nm wavelength.

• Dispersion Characteristics:

• The dispersion coefficient of single-mode fiber at 1550 nm wavelength is ≤18 ps/(nm·km), meeting the requirement of 50 km transmission without electrical relay in 10 Gbps systems.

• Cut-off Wavelength: ≤1260 nm for single-mode fiber and ≤1480 nm for multi-mode fiber, ensuring pure mode within the working wavelength range.

3.2 Mechanical and Mechanical Properties

• Tensile Performance:

• Long-term allowable tensile force: 600 N (for 8-12 core cables), short-term allowable tensile force: 1500 N, meeting the requirements of YD/T 901 standard.

• The aramid yarn layer extends the dynamic tensile fatigue life of the cable to ≥100,000 cycles (load ±20% of the rated tensile force).

• Compressive Performance:

• Long-term lateral pressure ≥300 N/100 mm, short-term lateral pressure ≥1000 N/100 mm. It can be increased to 2000 N/100 mm through steel tape armored structure optimization.

• Bending Performance:

• Static bending radius: 10 times the cable diameter, dynamic bending radius: 20 times the cable diameter. The bending loss at 1550 nm wavelength is ≤0.1 dB (curvature radius 30 mm).

3.3 Environmental Adaptability Performance

• Temperature Characteristics:

• Operating temperature range: -40°C to +70°C. The sheath hardness (Shore D) ≤75 at -40°C and the elongation rate ≥300% at +70°C.

• After temperature cycling test (-40°C to +70°C, 5 cycles), the fiber attenuation change is ≤0.05 dB/km.

• Waterproof Performance:

• Adopting full-section water-blocking design, no water seepage under 1 m water column pressure for 8 hours, meeting IEC 60794-1-F5B standard.

• The water absorption rate of the sheath material is ≤0.01% (23°C, 24 hours), effectively preventing water penetration.

• Anti-aging Performance:

• The polyethylene sheath passes the 1000-hour ultraviolet aging test (xenon lamp irradiation, 55°C) with a tensile strength retention rate of ≥80%.

4. Application Scenarios and Engineering Advantages

4.1 Typical Application Fields

• Power Communication Systems:

• In communication between 110 kV and above substations, the non-metallic structure avoids electromagnetic interference, and the cable grounding resistance is ≤10 Ω.

• When used in conjunction with OPGW (Optical Fiber Composite Overhead Ground Wire), it can 实现 dual-path transmission of power data and communication signals.

• Rail Transit Systems:

• When laid in subway tunnels, the cable outer diameter is ≤12 mm and the weight is ≤150 kg/km, facilitating installation along cable brackets.

• In high-speed rail communication, it supports stable transmission in low-temperature environments of -40°C with a bit error rate of ≤1×10⁻¹².

• Smart Grid Construction:

• In distributed energy access scenarios, the cable's lightning resistance passes the 10/350 μs waveform 80 kA impulse test (residual voltage ≤2 kV).

• In distribution network automation, it supports non-self-supporting overhead laying under 10 kV overhead lines with a span of ≤50 m.

4.2 Engineering Implementation Advantages

• Construction Convenience:

• The outer diameter of the cable is 15% smaller than that of GYTS cables with the same number of cores, increasing pipeline utilization by 20%. The air-blown laying speed can reach 80 m/min.

• The aramid sheath reduces the friction coefficient of the cable to ≤0.25, lowering the pipe-penetrating resistance by 40% compared to steel tape armored cables.

• Maintenance Economy:

• Using modular splice closures, the splicing time is ≤30 minutes/core, reducing maintenance costs by 30% compared to traditional metal armored cables.

• Over a 30-year design life cycle, the life cycle cost (LCC) is 25% lower than that of metal cables.

4.3 Special Scenario Adaptation

• Strong Electromagnetic Environments:

• The insulation resistance of the cable to ground is ≥10⁴ MΩ·km, and the induced voltage is ≤10 V under a 50 Hz, 10 kV electric field.

• The metal component content is ≤0.1%, meeting the requirements of GB/T 18015.1-2017 for non-flammable materials.

• Lightning-Prone Areas:

• When used in conjunction with lightning arresters, the cable grounding system can control the lightning current discharge time to ≤5 μs.

• The non-metallic structure reduces the probability of the cable attracting lightning by 90%, making it suitable for mountainous and open areas prone to lightning strikes.

5. Industry Standards and Certifications

• Domestic Standards:

• Complies with YD/T 901-2018 "Stranded Layer Type Outdoor Optical Cables for Communication" and has passed the Telcordia Certification (TLC).

• The flame retardancy meets the B1 level requirements of GB/T 19666-2019, with a smoke density rating (SDR) ≤15.

• International Certifications:

• Obtained UL 1581 certification with a combustion rating of VW-1, complying with IEC 60794-1-2003 standard.

• Environmentally friendly, passing the RoHS 2.0 certification with the content of harmful substances such as lead and mercury ≤0.1%.

6. Development Trends and Technological Innovations

1. Material Innovation:

• Using basalt fiber to replace part of FRP, raising the temperature resistance limit of the cable to +120°C, suitable for high-temperature industrial scenarios.

• Developing nano-composite sheath materials with an ultraviolet absorption rate increased to 98%, extending the anti-aging life to 50 years.

2. Structural Innovation:

• Integrating fiber optic sensors to 实现 distributed temperature monitoring (DTS) with a temperature measurement accuracy of ±1°C and a positioning accuracy of ±1 m.

• Adopting a micro-loose tube design (inner diameter 2.5 mm), increasing the core density to 288 cores/12 mm outer diameter to meet the requirements of 5G fronthaul.

3. Process Innovation:

• Applying laser welding technology to increase the bonding strength between FRP and the sheath to 50 N/cm, reducing the risk of interface peeling.

• Introducing an AI vision inspection system to improve the control accuracy of fiber excess length to ±0.05%, with an attenuation fluctuation of ≤0.02 dB/km.

7. Typical Engineering Cases

1. Interconnection Project of 110 kV Substations in Southern Power Grid:

• 30 km of GYHTY-48B1 optical cable was laid using a hybrid pipeline-overhead laying method. The bit error rate is ≤1×10⁻¹², meeting the real-time transmission requirements of relay protection signals.

2. Communication System of Beijing-Shanghai High-Speed Railway:

• 200 km of GYHTY-24B1 optical cable was laid along the railway, supporting 10 Gbps transmission in a low-temperature environment of -40°C with a jitter of ≤0.1 UI.

3. Smart Grid Demonstration Project in Xiongan New Area:

• GYHTY-96B6a optical cable was used, integrating DTS function to 实现 real-time temperature monitoring of cable joints with an early warning response time of ≤5 seconds.

8. Operation and Maintenance and Fault Handling

1. Daily Maintenance Points:

• Test the cable grounding resistance (≤10 Ω) and insulation resistance (≥10⁴ MΩ·km) quarterly.

• Conduct OTDR tests annually with an attenuation change threshold of 0.1 dB/km and a positioning accuracy of ±5 m.

2. Common Fault Handling:

• Fiber Breakage: Repair using a fusion splicer (fusion loss ≤0.05 dB) in conjunction with heat-shrinkable sleeves, taking ≤30 minutes per point.

• Sheath Damage: Repair using special repair patches (tensile strength ≥20 MPa), restoring the pressure resistance to 90% of the original sheath.

9. Selection and Configuration Recommendations

1. Core Number Selection:

• Access Network: 2-12 cores to meet the connection requirements of FTTH terminals.

• Backbone Network: 48-288 cores to support DWDM system expansion.

2. Environmental Adaptation:

• Strong Electricity Areas: Prioritize aramid-reinforced GYHTY with a metal component content of ≤0.1%.

• Humid Areas: Adopt a fully water-blocking structure with water-blocking yarn water absorption capacity ≥20 times its own weight.

3. Economic Analysis:

• Short-Term Projects: Select economical GYHTY (unit price approximately 8 yuan/meter) to meet basic communication needs.

• Long-Term Projects: Use high-reliability GYHTY (unit price approximately 12 yuan/meter) to reduce maintenance costs.

10. Future Outlook

1. Technological Evolution Direction:

• Develop Space Division Multiplexing (SDM) technology to 突破 the single-cable capacity of 1 Pb/s, supporting ultra-high-speed transmission in 6G networks.

• Integrate terahertz communication modules to 实现 optical cable-wireless fusion transmission with a coverage radius of ≤100 m.

2. Application Expansion Areas:

• Deep-Sea Communication: Through armor optimization (double-layer stainless steel tape), withstand a pressure depth of 3000 meters, supporting the construction of undersea observation networks.

• Space Communication: Use high-temperature-resistant sheaths (temperature resistance +200°C) to meet the interconnection requirements of near-Earth orbit satellite ground stations.

Note:

a.The suffix Xn in the model indicates the selected fiber type, see Yangtze Fiber Model Explanation for details.

b.The color arrangement of the loose tube and fibers can be found in the chromatogram.

c.The minimum thickness of the polyethylene sheath is 1.5mm.

d.The cable should not be stored in open-air environ- ments for more than 6 months, otherwise the spool may

   be damaged.

e.This document is for reference only and cannot be used as an attachment to the contract. For detailed product

   information, please contact our sales staff.