During offshore wind farm construction, cables are subjected to bending stresses caused by complex sea conditions, particularly at fixed ports, j-tube outlets, and dynamic cable connections. Without additional protection, excessive bending can easily damage the cable sheath or even break the core. The vertebra bend restrictor, with its unique structural design, has become a crucial device for ensuring safe cable operation.
Structural features of the vertebra bend restrictor
• Vertebra-like segmented structure: The vertebra bend restrictor draws inspiration from the structural principles of the biological spine and is constructed from multiple modular ring-shaped components.
• Combination of flexibility and rigidity: Each segmented unit interlocks to form a flexible yet robust protection system that moves with cable bending. Once bent to a set angle, it forms a "hard stop" to prevent further excessive bending.
• High-strength polyurethane material: The segments are often poured in one piece of polyurethane, offering excellent wear resistance, impact resistance, and seawater corrosion resistance, enabling stable operation in long-term underwater environments. Polyurethane's 1.17 density makes it lighter than typical metal bend limiters, making it easier to transport and install.
• Modular customization: Lengths can be increased or decreased to meet the needs of the application environment, offering enhanced processing and customization. Customization based on cable diameter, minimum bend radius, and operating depth facilitates installation, replacement, and maintenance.
Application scenarios in offshore wind farms
• J-tube and i-tube outlets: Cables are susceptible to bending damage due to currents and structural movement as they transition from the duct outlet to the free-hanging area. Spinal limiters effectively control the bend radius.
• Wind turbine tower cable entry: As cables enter the wind turbine foundation or booster station interface, limiters provide additional protection at the connection point, preventing damage from tension and angular fluctuations.
• Dynamic cable area: In floating wind farms, dynamic cables constantly sway with the floating structure. Spinal limiters, used in conjunction with buoyancy modules, significantly reduce fatigue and localized damage.
• Landing points and transition zones: Where submarine cables land on shore or in transition zones laid on complex seabeds, spine-shaped limiters are also suitable for installation to ensure uniform cable stress.
Application value
Prevents excessive cable bending and localized failures
Extends cable service life and reduces maintenance costs
Improves power transmission reliability in offshore wind farms
