Subsea Cable Hang-Off Device Armour Wire Assembly
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Solution Overview
Problem
Existing hang-off devices for subsea cables, which use a compound to mould the cable into the device for secure attachment, do not provide the highest level of safety and mechanical strength for attaching armoured power cables to offshore platforms.
Innovation Solution
A method and device that involves peeling, cutting, and bending armour wires radially outwardly, followed by assembling parts of the hang-off device around the cable, injecting a compound to fixate the wires, and electrically connecting them using an electrically conducting ring or compound to ensure uniform electric potential along the cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compound is injected into the hang-off body to mould the subsea cable into the hang-off device, then mechanical strength and security of attachment is improved, but the solution still does not provide the highest level of safety and the armour wires may have different electric potentials
Solution Approach 1:
An electrically conducting ring is introduced as an intermediary component between the armour wires to ensure electrical continuity. This ring serves as a mediator that connects all armour wires electrically, resolving the issue of different electric potentials while maintaining the compound-moulding method for mechanical strength.
Solution Approach 2:
The patent applies the equipotentiality principle by ensuring all armour wires are electrically connected through the conducting ring or compound, making them all at the same electric potential. This eliminates electrical hazards while maintaining the mechanical bonding provided by the compound.
2Ease of operation
If the armour is cut and bent radially outwardly for clamping, then ease of attachment is improved, but mechanical strength is reduced compared to compound moulding methods
Solution Approach 1:
The patent merges two attachment methods: the mechanical bending and clamping of armour wires for ease of operation, and the compound injection for high mechanical strength. The compound is injected after bending to mould and bond the bent armour wires, combining the advantages of both methods.
3Reliability
If an electrically conducting ring is provided between the armour wires to ensure electrical connection, then reliability is improved, but device complexity and assembly steps increase
Solution Approach 1:
The patent extracts the electrical connection function from the mechanical attachment process. The electrically conducting ring is a separate, dedicated component that solely provides electrical continuity, while the compound handles mechanical bonding. This separation of functions improves reliability of electrical connection.
4Device complexity
If the armour wires are not electrically connected, then assembly simplicity is maintained, but harmful electrical effects occur due to different electric potentials along the cable
Solution Approach 1:
The patent converts the potentially harmful effect of exposed armour wires with different electric potentials into a beneficial situation by providing electrical continuity through the conducting ring or conductive compound. This eliminates electrical hazards while the same structural arrangement provides mechanical strength.
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 solution provides a more secure and safe attachment of subsea cables to offshore platforms by enhancing mechanical strength and ensuring uniform electric potential across the cable, both above and below the hang-off device when mounted.
Implementation Method 1
a compound which is injected into the hang-off body and which solidifies therein to thereby mould the subsea cable into the hang-off device
Implementation Method 2
electrically connecting the first set of cut armour wires to the second set of cut armour wires after step c), wherein the step of electrically connecting is obtained by providing an electrically conducting ring between the first set of cut armour wires and the second set of cut armour wires
Data Source
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AI summary
The present disclosure relates to a method method of assembling hang-off device with an armoured power cable. The hang-off device is of the type which utilises a compound to mould an armoured wire into the hang-off device. The method comprises b) cutting the armour wires along the periphery of the armoured power cable thus obtaining a first set of cut armour wires and a second set of armour wires, d) bringing together and assembling a first part and a second part of the hang-off device, and e) injecting a compound into a mould chamber formed by the first part and the second part to fixate the first set of cut armour wires and the second set of armour wires within the hang-off device. During the assembly procedure, the first set of cut armour wires and the second set of cut armour wires are electrically connected. A hang-off device and a hang-off arrangement are also disclosed herein.