Selective Tertiary Winding Layout for Lower-Cost Transformers
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Solution Overview
Problem
Transformers with tertiary windings face high costs and risks of high short-circuit currents due to excessive winding sizes and power requirements, especially in systems with multiple wound limbs.
Innovation Solution
Designing a transformer with a single-phase core that includes primary and secondary windings on all limbs, but only one or more limbs with a tertiary winding, reducing the number of tertiary windings to minimize short-circuit currents and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a tertiary winding is added to all limbs of a transformer with multiple wound limbs, then the transformer can provide tertiary voltage system functions (fault current redistribution, neutral point voltage stabilization, zero sequence impedance reduction), but the manufacturing costs and short-circuit current risks increase significantly
Solution Approach 1:
The patent extracts the tertiary winding from only one specific limb (typically the middle limb in a three-limb core) rather than placing it on all limbs. This selective extraction maintains the essential function of providing a tertiary voltage system while significantly reducing the number of tertiary windings required, thereby lowering manufacturing costs and short-circuit current risks.
Solution Approach 2:
The patent applies local quality by making the tertiary winding configuration non-uniform across different limbs. Specifically, the middle limb is equipped with a tertiary winding while the outer limbs are not, creating a localized tertiary voltage system that is sufficient for fault current redistribution and neutral point stabilization without the excessive complexity of universal tertiary winding installation.
2Power
If multiple wound limbs are used in a high power transformer, then the transformer can meet power rating requirements, but the costs and short-circuit current risks are exacerbated when tertiary windings are added
Solution Approach 1:
The patent extracts the tertiary winding function to a single middle limb in multi-limb high power transformers, rather than distributing tertiary windings across all limbs. This approach maintains the ability to handle high power ratings through multiple limbs while concentrating the tertiary function in one location, thereby reducing overall short-circuit current exposure and manufacturing costs.
Solution Approach 2:
The patent implements local quality by equipping only the middle limb with a tertiary winding in high power transformers with multiple wound limbs. This localized configuration provides sufficient fault current redistribution capability and neutral point stabilization for the entire transformer system without requiring tertiary windings on all high-power limbs, thus reducing short-circuit current risks and costs.
3Reliability
If a tertiary winding is added to a transformer, then fault current redistribution and neutral point voltage stabilization are achieved, but manufacturing and maintenance costs increase due to larger minimum winding sizes
Solution Approach 1:
The patent extracts the tertiary winding from only one limb rather than all limbs, maintaining the essential fault current redistribution and neutral point voltage stabilization functions while significantly reducing the total amount of winding material required. This extraction approach lowers manufacturing and maintenance costs while preserving the core benefits of the tertiary voltage system.
Solution Approach 2:
The patent applies local quality by concentrating the tertiary winding function in a single middle limb, which provides sufficient fault current redistribution capability for the entire transformer system. This localized approach avoids the excessive manufacturing costs associated with installing tertiary windings on all limbs, making the solution economically viable while maintaining reliability.
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
Reduces short-circuit currents and manufacturing costs by half, allowing for more efficient use of resources and improved system operation.
Implementation Method 1
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit
Implementation Method 2
A transformer may have, in addition to primary and secondary windings, a tertiary winding
Data Source
AI summary
A transformer including a core, such as, for example, a single-phase core, that includes a plurality of wound limbs, primary and secondary concentric windings formed on each limb of the plurality of wound limbs, and at least one tertiary concentric winding formed on fewer than all limbs of the plurality of wound limbs.