High Voltage Cable with Rounded Conductor Corners
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Solution Overview
Problem
High voltage transformers face significant challenges in reducing eddy current losses, which are prevalent in the corners of conductors, leading to increased power losses and material costs due to existing solutions like multi-strand continuously transposed cables, which are expensive to manufacture and require substantial copper usage.
Innovation Solution
A cable design featuring conductors with rounded corners and a magnetic shield, where the corners have a radius between w/5 and w/3, with the space outside the corners filled with a magnetic material to minimize eddy current losses while maintaining DC loss efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multi-strand continuously transposed cables (CTC) are used to reduce eddy current losses, then eddy current losses are reduced, but manufacturing cost and material cost increase tremendously
Solution Approach 1:
The patent applies curvature by rounding the corners of the conductor cross-section. This geometric modification eliminates the sharp corners that generate high eddy current losses while maintaining a simple single-strand construction. The rounded corners reduce the concentration of magnetic flux and associated eddy currents without requiring complex multi-strand transposition structures, thereby achieving loss reduction with simpler and less expensive manufacturing.
Solution Approach 2:
The patent applies local quality by selectively modifying only the corner regions of the conductor cross-section. Instead of changing the entire conductor structure to multi-strand CTC, the invention locally rounds the corners where eddy current losses are most severe. This localized modification targets the specific problem area while maintaining the simplicity and cost-effectiveness of the overall single-strand conductor design.
2Loss of energy
If multi-strand continuously transposed cables (CTC) are used to reduce eddy current losses, then eddy current losses are reduced, but copper usage and material cost increase
Solution Approach 1:
The rounded corner geometry reduces eddy current paths and their intensity without requiring additional copper strands or transposition structures. The single rounded-corner strand uses less copper than an equivalent multi-strand CTC while achieving comparable or better eddy current loss reduction, directly addressing the material quantity concern.
Solution Approach 2:
The invention extracts and eliminates the need for complex multi-strand transposed structures by using a simple rounded-corner single strand. This extraction of the essential function (reducing eddy currents) from the complex CTC structure achieves the same or better performance with significantly reduced copper usage.
3Loss of energy
If conductor corners are rounded to reduce eddy current losses, then eddy current losses are reduced, but conductor cross-sectional area decreases
Solution Approach 1:
The patent optimizes the corner radius parameter to achieve the best compromise between eddy current loss reduction and cross-sectional area maintenance. By carefully selecting the rounding radius (not too small to be ineffective, not too large to excessively reduce area), the invention achieves significant eddy current loss reduction while minimizing the impact on conductor area and current-carrying capacity.
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 cable design effectively reduces eddy current losses by up to 50% compared to existing solutions, while maintaining DC loss efficiency, and can be used in high, medium, or low voltage applications, offering a cost-effective solution for high voltage applications.
Implementation Method 1
a layer comprising a magnetic material having a relative magnetic permeability in the range 2 to 100000, wherein the layer at least party surrounds the conductor
Implementation Method 2
Eddy current losses may thereby be reduced
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~4c
AI summary
The present disclosure relates to a cable (1) for a high voltage winding of an electromagnetic induction device. The cable (1) comprises a conductor (5) having a width w, and a shield (3) arranged around at least a portion of the conductor (5), wherein in any cross-section of the conductor (5) the conductor has rounded corners (5a) with a radius r in the range w/8<r≤w/2. A high voltage electromagnetic induction device comprising a cable forming a high voltage winding is also disclosed herein.