Pressurized Cable System for Underwater Turbine Nacelle Sealing
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Solution Overview
Problem
Kinetic Hydro Power (KHP) system turbines face challenges in maintaining a watertight seal due to rotating shaft seals, leading to water leakage into the nacelle, and require a solution to prevent water ingress while allowing for power and data transmission and pressurization of the nacelle.
Innovation Solution
A novel pressurized cable system with sealed ends and an open passageway along the length of power and data cables to maintain a positive pressure within the nacelle, using existing or purpose-built cables that allow for access to electrical connections while preventing air venting and water ingress, even when bent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If rotating shaft seals are used to allow rotor rotation, then mechanical power transmission is enabled, but water leakage into the nacelle occurs
Solution Approach 1:
A gas barrier (nitrogen or air) is introduced as an intermediary substance between the external water environment and the internal nacelle atmosphere. This gas barrier prevents water from penetrating through the rotating shaft seal by creating a pressure differential and physical barrier, while still allowing mechanical power transmission to occur.
Solution Approach 2:
An inert gas atmosphere (nitrogen or pressurized air) is maintained within the cable pathway and nacelle interior. This inert atmosphere prevents water ingress by creating a positive pressure environment that counteracts the external water pressure, allowing the rotating shaft seal to function without compromising watertight integrity.
2Object-affected harmful factors
If cable ends are sealed to prevent water ingress, then watertight integrity is improved, but pressurization capability is reduced
Solution Approach 1:
The cable system is segmented into multiple functional zones: a sealed outer jacket for watertight integrity, an internal gas pathway for pressurization, and electrical conductor pathways for power transmission. This segmentation allows each function to be optimized independently - the outer jacket prevents water ingress while internal channels enable pressurization.
Solution Approach 2:
The cable structure employs a nested configuration where the gas barrier and electrical conductors are contained within the sealed cable jacket. The gas pathway is nested within the cable structure, allowing pressurization to occur without compromising the external watertight seal. This nested design enables multiple functions within a single integrated component.
3Device complexity
If a single cable provides power, data, and pressurization, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
A single cable assembly is designed to perform multiple functions simultaneously: transmitting electrical power, carrying data signals, and providing pressurized gas barrier. The cable structure integrates separate pathways for each function within a unified sealed construction, eliminating the need for multiple separate cables and reducing overall system complexity.
Solution Approach 2:
The cable employs a composite structure combining multiple materials and functional layers: conductive materials for electrical pathways, barrier materials for gas sealing, and structural materials for mechanical strength. This composite construction allows the single cable to achieve multiple functions while maintaining manufacturability through standardized material combinations.
4Object-affected harmful factors
If positive pressure is maintained in the nacelle, then water ingress is prevented, but energy consumption increases
Solution Approach 1:
The cable is pre-charged with pressurized gas during installation, establishing the positive pressure barrier before the turbine begins operation. This preliminary pressurization creates an immediate water barrier, and the sealed cable construction maintains this pressure without requiring continuous energy input, reducing ongoing energy consumption.
Solution Approach 2:
The pressurized gas within the cable serves a dual function: it maintains the watertight barrier and simultaneously provides structural support to the cable jacket. The internal pressure prevents external water pressure from deforming or damaging the cable, allowing the cable to protect itself without additional energy input or external support structures.
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 solution effectively prevents water ingress into the nacelle, maintains a positive pressure environment, and allows for monitoring of pressure changes, minimizing the impact of cable punctures and ensuring reliable operation of the turbine.
Implementation Method 1
use is made of the cable's ability of conducting gases, either through the spaces between wires within the cable, or via a separate gas channel, to link a pressure source to the interior of the nacelle to thereby maintain a positive pressure in the nacelle in order to counteract the inward pressure of the surrounding water
Implementation Method 2
sealing the cable ends to prevent air from venting through cables connecting under water power turbine to onshore control facility
Implementation Method 3
cable connections are needed so that the generated power can be transmitted from the turbine onto the power grid or other load and the electrical signals can be sent to or received from the turbine at an onshore control facility
Data Source
AI summary
An underwater power generating system includes an underwater power generating device, a closed nacelle and a connecting cable system that is provided with an open passage way extending there along that is sealed at one end to the interior of the closed nacelle. The cable system can be used in a number of ways, such as by having the second end being sealed, to prevent air from escaping the closed nacelle, or by having the second end connected to a source of positive pressure thereby permitting the cable to be sufficiently pressurized to provide a positive pressure internally within the closed nacelle that is at least slightly greater than the nacelle at depth pressure, and thus greater than water pressure acting on the exterior of the closed nacelle, to prevent water ingress within the nacelle, as well as to transmit power and/or other data between the nacelle and shore monitoring and control facilities.