Magnetic Layer Cable Reduces Eddy Current Losses
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Solution Overview
Problem
Large transformers face significant challenges in reducing power losses due to eddy current losses, which are exacerbated by high voltage and current handling, leading to increased material costs and operational inefficiencies.
Innovation Solution
A cable for electromagnetic device windings is proposed, featuring a conductor surrounded by a layer of magnetic material with high relative permeability, which redistributes leakage flux and reduces eddy current losses, allowing for a more efficient operation and potentially lower manufacturing costs by using fewer and thicker strands.
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 the cost of copper material and manufacturing increases tremendously
Solution Approach 1:
A magnetic layer with high relative permeability (μr > 100) is introduced as an intermediary between the conductor and the surrounding environment. This magnetic layer redirects leakage flux away from the conductor, reducing eddy current losses without requiring complex multi-strand transposed cable structures. The magnetic layer acts as a flux shunt, providing a preferred path for leakage flux and thereby protecting the conductor from excessive eddy current heating.
Solution Approach 2:
The cable structure combines conventional conductor material with a magnetic material layer having high relative permeability. This composite structure leverages the magnetic properties of the magnetic layer to control flux distribution and reduce eddy current losses in the conductor, achieving loss reduction without the need for expensive multi-strand transposed configurations.
2Ease of manufacture
If thicker and fewer strands are used in the cable, then manufacturing cost is reduced, but eddy current losses increase
Solution Approach 1:
The magnetic layer serves as a protective intermediary that enables the use of thicker, fewer strands by compensating for the increased eddy current losses that would otherwise result from such a configuration. The magnetic layer redirects leakage flux before it can induce excessive eddy currents in the thicker conductor strands.
3Strength
If stronger copper material with higher yield strength is used, then the cable can withstand short circuit forces better, but material cost increases
Solution Approach 1:
The magnetic layer acts as a protective intermediary that reduces the mechanical stress and thermal loading on the conductor during short circuit conditions by redirecting leakage flux. This allows the use of conventional strength copper materials rather than requiring expensive high-strength copper alloys, as the magnetic layer absorbs part of the electromagnetic stress.
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 5-10% reduction in eddy current losses, enhances the ability to withstand short circuit currents, and reduces the need for expensive copper materials, thereby improving efficiency and cost-effectiveness for high voltage applications.
Implementation Method 1
a layer comprising a magnetic material having a relative permeability in the range 2 to 100000, wherein the layer at least party surrounds the conductor
Implementation Method 2
the leakage flux will redistribute to be partially confined to the layer and thereby substantially reduce the eddy current losses in the conductor
Implementation Method 3
due to the magnetic material, more magnetic energy can be stored in the cable and thus the winding, whereby the ability of large electromagnetic devices to withstand the occurring force due to short circuit current is improved
Data Source
AI summary
A cable for winding of an electromagnetic device. The cable includes a conductor, and a layer including a magnetic material having a relative permeability in the range 2 to 100000, wherein the layer at least partly surrounds the conductor.