Power Cable Inner Semi-Conductive Layer Design
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Solution Overview
Problem
Power cables face deterioration of dielectric strength due to copper powder penetration from the conductor into the insulating layer, leading to reduced lifespan and damage to insulating and semi-conductive papers, especially when bent or unfolded, which affects bendability, flexibility, and installability.
Innovation Solution
A power cable design featuring an inner semi-conductive layer formed by overlap-winding semi-conductive paper with an overlap ratio of 20-80% and a structure including multiple layers of insulating paper impregnated with oil, where the inner and outer insulating layers have lower resistivity and the intermediate layer has higher resistivity, preventing copper powder movement and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gap winding is used to form insulating layer and inner semi-conductive layer, then moving path of insulating oil is secured, but copper powder penetrates into insulating layer causing dielectric strength deterioration
Solution Approach 1:
The patent applies different winding methods to different layers: gap winding for the insulating layer to maintain oil circulation paths, and overlap winding for the inner semi-conductive layer to prevent copper powder penetration. This local differentiation resolves the contradiction by optimizing each layer's structure for its specific function.
Solution Approach 2:
The patent segments the winding structure into distinct functional zones: the insulating layer with gap winding for oil flow, and the inner semi-conductive layer with overlap winding as a barrier against copper powder. This segmentation allows each segment to address specific requirements without compromising the other.
2Ease of operation
If insulating paper is wound in multiple layers with gaps, then insulating oil can circulate, but copper powder disperses in insulating oil and penetrates insulating layer
Solution Approach 1:
The inner semi-conductive layer formed by overlap winding acts as an intermediary barrier between the conductor and the insulating layer. It prevents copper powder from reaching the insulating layer while allowing the insulating oil to circulate through the gap-wound insulating layer above it.
Solution Approach 2:
The patent creates a localized barrier structure in the inner semi-conductive layer using overlap winding, while maintaining gap winding in the insulating layer for oil circulation. This local quality differentiation addresses both requirements simultaneously.
3Adaptability or versatility
If insulating paper is repeatedly bent and unfolded, then cable installation is flexible, but insulating paper and semi-conductive paper are damaged
Solution Approach 1:
The overlap-wound inner semi-conductive layer acts as a cushioning structure that absorbs and distributes mechanical stress during bending and unfolding operations. This prevents direct stress transmission to the insulating paper layers, protecting them from damage while maintaining cable flexibility.
Solution Approach 2:
The patent uses composite paper structures with specific material compositions that combine flexibility with structural integrity. The layered composite structure of insulating paper and semi-conductive paper, combined with the overlap winding technique, creates a resilient interlayer structure that withstands repeated bending.
Data Source
AI summary
Provided is a power cable, and more particularly, to an ultra-high-voltage underground or submarine cable. In detail, the present invention relates to a power cable which is capable of effectively preventing a decrease in dielectric strength due to penetration of copper powder from a copper conductor into an insulating layer, thereby increasing the lifespan thereof, is capable of preventing damage to insulating paper, semiconductor paper, etc. even when repeatedly bent and unfolded, thereby maintaining an interlayer structure formed by winding the insulating paper, the semiconductor paper, etc., and is capable of improving bendability, flexibility, installability, workability, etc.