DC Cable Termination Box Uniform Resistance Distribution
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Solution Overview
Problem
Existing termination connection boxes for DC power cables face challenges in achieving uniform resistance distribution and preventing local electric field concentration, leading to insulating performance degradation and complex installation processes.
Innovation Solution
A termination connection box design featuring a heat shrinkable tube with non-linear electrical characteristics, electrically connected to both the conductor and outer semiconducting layer, and a thicker section to distribute resistance uniformly, preventing electric field concentration and improving insulating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistive paint is applied onto the insulator surface to divide the electric field, then the electric field distribution is improved, but the manufacturing process becomes complex and time-consuming due to repeated applications
Solution Approach 1:
The patent changes the physical state of the resistive material from liquid paint to solid granules or powder. This allows the material to be applied as a coating layer that can be uniformly distributed on the insulator surface without requiring repeated painting operations. The solid form enables easier handling, uniform application, and eliminates the complexity of maintaining uniform paint thickness.
2Manufacturing precision
If resistive paint is applied to achieve uniform thickness for electric field division, then the resistance distribution is improved, but foreign substances like moisture can penetrate the interface between insulator and paint
Solution Approach 1:
The patent uses a composite structure consisting of the insulator material combined with resistive granules or powder coating. This composite approach creates a robust interface where the granular resistive material fills surface irregularities and forms a mechanically interlocked bond with the insulator, preventing moisture penetration while maintaining uniform electrical resistance distribution.
3Manufacturing precision
If a field grading material layer is formed by coating or painting to achieve uniform thickness, then the resistance distribution is improved, but it is very difficult to prevent foreign substances from penetrating the layer
Solution Approach 1:
The patent applies resistive granules or powder that conform to the local surface topology of the insulator. The granular material adapts to surface irregularities and creates a mechanically interlocked structure that is resistant to foreign substance penetration. This local adaptation ensures uniform electrical properties while providing robust physical protection.
4Manufacturing precision
If a field grading material layer is formed in the form of sleeve to achieve uniform thickness, then the thickness is improved, but it is difficult to prevent voids from being generated in the layer
Solution Approach 1:
The patent employs a porous or granular resistive material coating that can accommodate volume changes and thermal expansion without forming voids. The granular structure allows for better stress distribution and eliminates the formation of vacuum pockets that occur with solid sleeve structures, ensuring uniform contact and eliminating voids while maintaining thickness uniformity.
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 achieves a uniform resistance distribution and reduces electric field concentration, enhancing the insulating performance and simplifying the installation process by maintaining a uniform electric field and effectively managing space charges.
Implementation Method 1
a heat shrinkable tube configured such that one portion thereof covers an outer circumferential surface of the cable insulating layer
Implementation Method 2
A termination connection box design featuring a heat shrinkable tube with non-linear electrical characteristics, electrically connected to both the conductor and outer semiconducting layer, and a thicker section to distribute resistance uniformly
Data Source
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AI summary
The present invention is to provide a termination connection box for a direct-current (DC) power cable, which is capable of achieving a uniform resistance distribution and decreasing a resistance value.