Cold-Shrink Cover Assembly for Electrical Cable Insulation
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Solution Overview
Problem
Electrical connections in harsh environments, such as water-filled ducts or buried under rocks, face integrity issues due to exposure of bare metal surfaces, leading to potential failures and safety risks. Additionally, splice connections can experience high electric potential differences and voltage stresses due to magnetic induction, necessitating effective shielding and insulation solutions.
Innovation Solution
A cold-shrink cover assembly comprising an integral inner sleeve, Faraday cage layer, stress cone layers, semiconductor layer, and outer sleeve, which can be pre-expanded and installed over electrical connections to provide insulation and shielding, reducing voltage stress and preventing environmental ingress, while allowing for a controlled shield break to prevent lossy circulating currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cold-shrink cover assembly with multiple layers is used to provide comprehensive insulation and shielding, then the protection against environmental factors and voltage stress is improved, but the device complexity and installation difficulty increase
Solution Approach 1:
The patent combines multiple protective functions (insulation, shielding, environmental protection) into a single integrated cold-shrink cover assembly that contracts as one unit, merging what would traditionally be separate protective layers into a unified structure that simplifies installation while maintaining comprehensive protection
Solution Approach 2:
The cover assembly employs a nested structure with an inner sleeve containing the Faraday cage layer, which is itself contained within the outer sleeve. These nested layers collectively contract onto the cable connection, providing multiple levels of protection while maintaining a compact, integrated form factor
2Ease of operation
If the cover assembly is pre-expanded for easier installation, then the ease of operation is improved, but the volume and storage requirements increase
Solution Approach 1:
The cover assembly is pre-expanded at the factory to a larger diameter that facilitates easy installation over the cable connection. After installation, the assembly automatically contracts to its final compact size through the cold-shrink mechanism, combining ease of installation with space-efficient storage
3Loss of energy
If a controlled shield break is implemented to prevent circulating currents, then the energy loss is reduced, but the voltage stress on the connection increases
Solution Approach 1:
The Faraday cage layer acts as an intermediary between the cable shields, providing a controlled break point that interrupts circulating currents while the insulating layers and stress cone structures mediate the voltage distribution, preventing excessive voltage stress at the break point
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 effectively insulates and shields electrical connections, reducing the risk of failure and ensuring safety by maintaining cable integrity and withstanding high voltages, while simplifying installation and reducing costs through lower craft sensitivity and ease of use.
Implementation Method 1
a pre-expanded unit including a holdout device, wherein the cover assembly is in an expanded state
Implementation Method 2
Faraday cage layer
Implementation Method 3
stress cone layers, semiconductor layer
Data Source
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AI summary
A cover assembly for covering and electrically insulating an electrical connection includes a joint body including a tubular inner sleeve and an integral semiconductor layer. The inner sleeve is formed of an elastically expandable, electrically insulating material and having an outer surface and opposed first and second terminal ends. The inner sleeve defines a through passage extending axially from a first end opening at the first terminal end of the inner sleeve to a second terminal end opening at the second end of the inner sleeve. The semiconductor layer is disposed on the outer surface of the inner sleeve and is formed of an electrically semiconductive material. The semiconductor layer extends axially from a first terminal end of the semiconductor layer to an opposing second terminal end of the semiconductor layer. The first terminal end of the semiconductor layer is spaced apart from the first terminal end of the inner sleeve a prescribed semiconductor truncation distance to define a tubular band of the outer surface that is not covered by the semiconductor layer.