Subsea Electrical Feedthrough Assembly With Piston Pressure Compensation
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Solution Overview
Problem
Deploying reliable and efficient power systems for subsea oil and gas operations is challenging due to high pressures and corrosive seawater, which complicates maintenance and requires equipment to withstand extreme conditions for extended periods without surface access.
Innovation Solution
An electrical feedthrough assembly comprising a lower and upper assembly with conductors enclosed in insulators, a piston for pressure compensation, and dielectric fluid to maintain isolation and balance pressure, allowing for conductive connection and power transmission to subsea devices without the need for complex bladder systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cable terminators and connectors are used to penetrate through subsea trees, then power can be provided to subsea devices, but the system becomes complex and requires multiple fluid profiles and elastomer seals
Solution Approach 1:
The patent extracts and eliminates the complex bladder system with multiple fluid profiles and elastomer seals from the conventional cable terminator design. By removing these unnecessary components and replacing them with a simplified feedthrough assembly that uses a single dielectric fluid, the system complexity is reduced while maintaining power transmission reliability through the subsea tree.
Solution Approach 2:
The patent merges the electrical connection and pressure compensation functions into a single integrated feedthrough assembly. The upper and lower feedthroughs are coupled together to form a unified structure that provides both electrical conductivity and pressure balance, eliminating the need for separate complex systems and reducing overall device complexity.
2Reliability
If equipment is designed to withstand 300 bar pressure at 3000m depth, then reliability in subsea environment is improved, but manufacturing and installation costs increase
Solution Approach 1:
The feedthrough assembly incorporates a piston that automatically responds to pressure differentials between the dielectric fluid and the external environment. This self-adjusting mechanism maintains pressure balance without requiring complex external control systems or expensive specialized components, thereby achieving pressure resistance at reduced manufacturing cost.
Solution Approach 2:
The patent uses a dielectric fluid with specific pressure-compensating properties that allows the system to adapt to deep-sea pressure conditions. By selecting appropriate fluid parameters and designing the piston to respond to pressure changes, the system achieves 300 bar pressure resistance through material and design parameter optimization rather than through costly over-engineering.
3Ease of operation
If long tieback power transmission systems are used for onshore generating stations, then power can be transmitted to remote subsea devices, but power losses and reactive power increase
Solution Approach 1:
The feedthrough assembly acts as an intermediary component that enables efficient power transmission from onshore generating stations to remote subsea devices. By providing a reliable, low-loss electrical connection through the subsea tree with proper dielectric isolation and pressure compensation, the system minimizes power losses and reactive power in the long tieback transmission system.
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 cost-effective, reliable, and safe means of powering subsea equipment by eliminating the need for multiple fluid profiles and elastomer seals, enhancing operational safety and longevity while minimizing manufacturing and installation costs.
Implementation Method 1
a dielectric fluid provided within the chamber. The piston may be movable within the channel in response to a pressure differential between the dielectric fluid and the outside of the outer body
Implementation Method 2
The piston may be movable within the channel in response to a pressure differential between the dielectric fluid and the outside of the outer body
Implementation Method 3
a piston disposed within the channel and configured to fluidly isolate the chamber from the outside of the outer body, and a dielectric fluid provided within the chamber
Implementation Method 4
a first conductor extending from the lower housing to the upper housing, wherein at least one portion of the first conductor is enclosed in a first insulator
Data Source
AI summary
An electrical feedthrough assembly may include a lower assembly and an upper assembly coupled together. The lower assembly may include an outer body with a lower housing and an upper housing disposed within a bore of the outer body, and a first conductor extending from the lower housing to the upper housing. Additionally, the upper assembly may include an outer body with a pin end, the pin end is inserted into an opening of the lower assembly, a main body connected to the outer body, a second conductor disposed within the main body, a channel in the outer body open to an outside of the outer body and a chamber within the outer body, a piston disposed within the channel and configured to fluidly isolate the chamber from the outside of the outer body, and a dielectric fluid provided within the chamber.