Cryogenic High Voltage Bushing Thermal Stress Management
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Solution Overview
Problem
Conventional high voltage bushings fail due to thermal stress caused by large temperature differences between ambient and cryogenic environments in superconducting devices, necessitating a reliable connection structure that minimizes thermal losses.
Innovation Solution
A high voltage bushing with a first portion for ambient temperature and a second portion for cryogenic temperature, featuring a base insulator and an environmental protection layer on the ambient portion, along with a sealing mechanism to accommodate temperature transitions and withstand environmental hazards, while ensuring minimal thermal conduction losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional high voltage bushing is used to connect ambient temperature equipment to cryogenic superconducting elements, then electrical connection is achieved, but thermal stress causes failure due to large temperature differences
Solution Approach 1:
The bushing is divided into multiple sections with different materials optimized for different temperature zones. The ambient temperature portion uses standard insulating materials, while the cryogenic portion uses materials specifically selected for low-temperature performance, allowing each section to withstand its local thermal conditions without causing failure at the interface.
Solution Approach 2:
Different portions of the bushing are constructed with different material properties tailored to their specific thermal environments. The transition zone between ambient and cryogenic sections uses graduated material properties to manage thermal stress distribution, ensuring that no single point experiences excessive stress that would lead to failure.
2Loss of energy
If thermal insulation is increased to reduce thermal losses, then energy efficiency improves, but thermal stress management becomes more difficult
Solution Approach 1:
A transition section acts as an intermediary between the thermally insulated cryogenic portion and the ambient environment. This intermediate zone gradually transitions thermal properties, allowing heat insulation to be effective in the cryogenic section while distributing thermal stress across the transition zone rather than concentrating it at a single interface.
3Ease of manufacture
If the bushing structure is simplified for ease of manufacture, then manufacturing cost decreases, but ability to accommodate temperature transitions and environmental hazards is reduced
Solution Approach 1:
The bushing employs composite construction combining multiple materials in a structured assembly. While the overall structure remains relatively simple for manufacturing, the composite nature allows different sections to be optimized for their specific functions - electrical insulation, thermal management, and environmental protection - without requiring complex integrated designs.
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 bushing effectively manages thermal stresses and maintains reliability across temperature extremes, preventing failure and ensuring efficient operation in cryogenic applications by reducing thermal conduction losses and protecting against environmental factors.
Implementation Method 1
The first bushing portion may further comprise an environmental protection layer disposed over the base insulator portion
Implementation Method 2
a sealing mechanism to accommodate temperature transitions
Implementation Method 3
ensuring minimal thermal conduction losses
Data Source
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AI summary
An electrical bushing is disclosed for use in high voltage cryogenic applications. The bushing including first and second bushing portions and an electrical conductor disposed longitudinally within the portions. The electrical conductor has a first terminal extending from the first bushing portion and a second terminal extending from the second bushing portion. The first terminal is configured to couple to a first electrical element at ambient temperature, and the second terminal is configured to couple to a second electrical element at cryogenic temperature. The first and second bushing portions comprise a base insulator material, while the first bushing portion further comprises an environmental protection layer disposed over the base insulator portion.