Parallel Star-Delta Transformer Layout With Fewer Busbar Crossovers

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Solution Overview

Problem

Connecting transformers in parallel in power transmission networks results in a large footprint, increased material costs, and complex maintenance due to overlapping bus works and height separation requirements, especially in high voltage applications, while using non-identical transformers increases design and testing costs.

Innovation Solution

An electrical arrangement using two star-delta transformers with the same phase relationship between their primary and secondary winding sides, optimizing the connection to minimize crossovers and reduce the need for additional height and material, while maintaining the same phase relationship for AC input and output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two identical star-delta transformers are connected in parallel with conventional wiring arrangements, then the phase relationship is maintained and redundancy is provided, but the number of electrical crossovers increases requiring height separation and increasing footprint

Engineering Contradiction:
ImproveredundancyVSAvoidfootprint
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent reconfigures the spatial arrangement of electrical connections by changing the dimensional layout of busbars and connection points. Instead of conventional wiring that requires vertical height separation, the invention arranges connections in a planar configuration where busbars are positioned at different horizontal locations, eliminating the need for height separation while maintaining electrical isolation through proper spatial positioning.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If two identical star-delta transformers are connected in parallel, then the same phase relationship is maintained, but overlapping bus works require complex insulation and height separation

Engineering Contradiction:
Improvephase relationship consistencyVSAvoidinsulation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention eliminates the need for complex insulation by transitioning from a vertical stacking arrangement to a horizontal planar arrangement. Busbars that would otherwise overlap in the vertical dimension are redistributed across different horizontal positions, allowing electrical connections to be made without requiring insulation between overlapping conductors.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent extracts the insulation requirement from the connection design by removing the need for vertical separation. Through clever routing of busbars and positioning of connection points, the design achieves electrical isolation through spatial separation in the horizontal plane rather than relying on insulation materials and vertical clearance.

Inventive Principle:
Principle #2Taking out (Extraction)

3Area of stationary object

If non-identical transformers are used to reduce crossovers, then design footprint is reduced, but design and testing costs increase

Engineering Contradiction:
ImprovefootprintVSAvoiddesign cost
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent introduces asymmetry in the connection arrangement rather than in the transformer units themselves. While the transformers remain identical (maintaining manufacturing simplicity), the busbar routing and connection point positioning are arranged asymmetrically to minimize crossovers and eliminate the need for height separation, achieving compact footprint without increasing design complexity.

Inventive Principle:
Principle #4Asymmetry

4Ease of operation

If conventional parallel connection arrangements are used, then transformers are easily connected, but additional height separation increases material costs

Engineering Contradiction:
Improveconnection simplicityVSAvoidmaterial cost
Core Design Contradiction:
Ease of operationVSWeight of stationary object

Solution Approach 1:

The invention reduces material costs by eliminating the need for vertical height separation structures. By redistributing electrical connections in the horizontal plane with optimized busbar routing and strategically positioned connection points, the design achieves the same electrical isolation function without requiring additional insulators, support structures, or vertical clearance space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4645627A1Improvements relating to connecting transformers in parallel in power transmission networks
Publication Date: 2025.11.05 GENERAL ELECTRIC TECH GMBH
  • EP4645627A1 patent drawingFigure 1
  • EP4645627A1 patent drawingFigure 2
  • EP4645627A1 patent drawingFigure 3

AI summary

There is provided an electrical arrangement (400) for a power transmission network, comprising first and second transformers (410, 420) of the star-delta type, each having respective primary (412, 422) and secondary (414, 424) winding sides. The primary winding side (412, 422) of each transformer (410, 420) comprises three AC electrical connections (Y1, Y2, Y3, Y1', Y2', Y3'). The secondary winding side (414, 424) of each transformer (410, 420) comprises three AC electrical connections (d1, d2, d3, d1', d2', d3'). The transformers (410, 420) are arranged such that AC electrical connections (Y3, d3) of the first transformer (410) that are spatially adjacent AC electrical connections (Y1', d1') of the second transformer (420) are connected together. Remaining AC electrical connections (Y1, Y2, Y2', Y3', d1, d2, d2', d3') are connected so as to allow the first transformer (410) and second transformer (420) to have the same phase relationship.