Bend Stiffener Cooling for Higher-Current Dynamic Submarine Cables
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Solution Overview
Problem
Dynamic submarine power cables connected to floating offshore structures experience hot spots due to low thermal conductivity in bend stiffeners, limiting the maximum current capacity.
Innovation Solution
Incorporating a fluid flow device within the bend stiffener to generate forced cooling, reducing the temperature of the cable and allowing higher current transmission by creating a longitudinal channel for airflow or fluid flow along the cable route.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bend stiffener is used to control the bending radius and reduce fatigue loads of the cable, then the cable's mechanical reliability is improved, but the low thermal conductivity of the bend stiffener causes a hot spot that limits the maximum current capacity
Solution Approach 1:
A cooling fluid (air or liquid) is introduced as an intermediary substance between the heat source (cable conductor) and the environment. The fluid flows through the longitudinal channel in the bend stiffener, absorbing heat from the cable and transporting it away, thus mediating the thermal management without compromising the mechanical protection provided by the bend stiffener
Solution Approach 2:
The patent applies pneumatic or hydraulic cooling by forcing a fluid through a channel within the bend stiffener structure. The fluid flow (driven by pressure differential created by fans or pumps) removes heat from the cable conductor through convection, enabling higher current capacity while maintaining the bend stiffener's mechanical function
2Reliability
If the maximum current in the dynamic submarine power cable is determined by the temperature in the power cable through the bend stiffener, then the cable operating safety is ensured, but the current capacity is limited by the hot spot region
Solution Approach 1:
The cooling fluid acts as a thermal intermediary that selectively removes heat from the cable conductor in the bend stiffener region without interfering with the electrical current transmission. This allows the cable to operate at higher currents while the fluid maintains the temperature within safe limits through continuous heat extraction
Solution Approach 2:
The patent changes the thermal parameters of the cable system by introducing forced convection cooling. This alters the temperature distribution and maximum operating temperature of the cable, enabling higher current capacity while maintaining safety margins through active thermal management
3Ease of manufacture
If the cross-section of the conductor is reduced to lower costs, then the manufacturing cost is decreased, but the current capacity and power transmission capability are reduced
Solution Approach 1:
The cooling fluid continuously removes heat from the conductor along its length within the bend stiffener, maintaining a lower temperature throughout the cable run. This continuous cooling allows the use of smaller conductor cross-sections that would otherwise overheat, thereby reducing material costs while maintaining adequate current capacity for power transmission
Solution Approach 2:
By changing the thermal environment of the conductor through forced cooling, the patent enables the use of conductors with smaller cross-sectional areas. The altered thermal parameters (lower operating temperature, improved heat dissipation) allow cost-effective conductor designs to achieve the required power transmission capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The forced cooling effectively reduces the maximum conductor temperature, enabling higher current transmission without exceeding the allowed temperature, potentially reducing the conductor cross-section size and enhancing system efficiency.
Implementation Method 1
a fluid flow device configured to generate a fluid flow inside the longitudinal channel... the hot spot region of the dynamic submarine power cable is cooled by forced cooling by means of the fluid flow device
Data Source
Figure 1~2
AI summary
An offshore system (1) comprising: a dynamic submarine power cable (11), a bend stiffener (9) having a lower end (9b) and a top end (9a), the bend stiffener (9) having a central channel extending from the lower end (9b) to the top end (9a), the central channel receiving the dynamic submarine power cable (11) with a radial spacing between an inner surface of the central channel and an outer surface of the dynamic submarine power cable (11) along the length of the dynamic submarine power cable (11) arranged in the bend stiffener (9), the radial spacing forming a longitudinal channel between the bend stiffener (9) and the dynamic submarine power cable (11), and a fluid flow device (13) configured to generate a fluid flow inside the longitudinal channel.