Cable Installation Through Variable-Diameter Ducts Using Hydraulic Pigs
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Solution Overview
Problem
Existing methods for laying power cables into ducts, especially over long distances and between windmills offshore, are inefficient due to differences in duct diameters and require complex processes that are not well-suited for long-distance installations.
Innovation Solution
A method involving the use of pigs attached to the cable, with liquid pressure adjustments to facilitate smooth cable transfer between ducts of different sizes, allowing for efficient and automated cable laying by compensating for flow and volume differences, enabling simultaneous installation of multiple cables and reducing installation time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single fluid pressure system is used to transport cable through ducts of different diameters, then the process is simple, but the cable cannot be efficiently transported through ducts with different sizes
Solution Approach 1:
The fluid pressure system is segmented into multiple independent pressure zones, each controlling a specific duct section. This allows each duct (regardless of diameter) to have optimized pressure and flow parameters, enabling efficient cable transport through varying duct sizes while maintaining overall process control.
Solution Approach 2:
The system dynamically adjusts fluid pressure and flow rates for each duct section based on real-time cable position and duct characteristics. This dynamic control enables the system to adapt to different duct diameters and lengths, optimizing transport efficiency without requiring a completely different system for each duct.
2Speed
If cable is continuously propelled through multiple ducts, then installation speed is high, but flow and volume differences between ducts cause instability and potential cable damage
Solution Approach 1:
The system pre-calculates and pre-adjusts fluid pressure and flow parameters for each duct section before cable arrival. This preliminary configuration ensures smooth transitions between ducts of different sizes, preventing cable instability and damage while maintaining high installation speeds.
Solution Approach 2:
The system incorporates feedback mechanisms that continuously monitor cable position, speed, and duct conditions. This real-time feedback allows the control system to adjust fluid pressure and flow rates dynamically, ensuring stable cable transport through ducts of varying diameters while maintaining high installation velocity.
3Ease of manufacture
If pigs are removed and replaced at duct transitions, then the process is simple, but installation time increases significantly
Solution Approach 1:
The system maintains continuous cable propulsion through multiple ducts without stopping to remove or replace pigs. The fluid pressure system is configured to automatically adapt to different duct sections, allowing the cable to flow continuously from one duct to another, thereby eliminating time-consuming intervention operations.
Solution Approach 2:
The pig design is universalized to function across multiple duct types and sizes. The pig can traverse duct transitions and adapt to different diameters without requiring removal or replacement, making the same pig multi-functional for the entire duct network and significantly reducing installation time.
4Adaptability or versatility
If offshore cable laying operations are extended, then more windmills can be connected, but operation costs and complexity increase
Solution Approach 1:
The offshore duct network is segmented into modular sections that can be independently configured and activated. This segmentation allows the system to connect additional windmills by simply activating new duct segments rather than reconfiguring the entire system, thereby reducing operational complexity while increasing adaptability.
Solution Approach 2:
The fluid pressure system is designed to dynamically allocate pressure and flow resources to different duct sections based on operational requirements. This dynamic resource allocation enables the system to efficiently manage cable laying to multiple windmills without proportionally increasing operational complexity, as the system automatically optimizes resource distribution.
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
This method enables efficient and smooth laying of power cables across ducts of varying diameters, optimizing cable speed and reducing installation time and costs by allowing simultaneous cable laying and minimizing the need for offshore operations.
Implementation Method 1
introducing a liquid at first pressure and first flow into the first duct, for transporting the cable equipped with the first pig through the first duct
Implementation Method 2
compensating, until the first pig reaches the exit of the first duct, at a location between the first duct and second duct, for a difference in flow or volume of liquid
Data Source
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AI summary
Method for installing a cable comprising: • a first phase with at least the steps of: - introducing the cable into a first duct, - attaching at least a first pig to the cable, - introducing a liquid at first pressure and first flow into the first duct, - stopping the cable when, or after, its foremost end has reached an exit of the first duct, • a second phase with at least the steps of: - attaching at least a second pig to the cable, - introducing again a liquid at first pressure and first flow into the first duct, - introducing the liquid at second pressure and second flow, - compensating, at a location between the first duct and second duct, for a difference in flow or volume of liquid.