Segmented Transformer Windings for Dielectric Test Maintenance

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Solution Overview

Problem

Existing single-phase transformers for dielectric tests are bulky and require replacement of entire windings upon damage, leading to increased intervention times and costs, especially for high insulation classes like 400/500 kV, which complicates maintenance and is economically disadvantageous.

Innovation Solution

The transformer features 'cigar' windings composed of independent elementary coils with electrical connections that allow for smaller coil sizes, enabling the replacement of only the damaged coil instead of the entire winding, simplifying maintenance and assembly while maintaining equivalent electrical performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional single-stage cigar windings are used in transformers for dielectric tests, then the transformer can achieve the required electrical performance and insulation class (e.g., 400/500 kV), but the windings become huge in size and complicate fitting operations, making maintenance and repair difficult and expensive

Engineering Contradiction:
Improveelectrical performance and insulation classVSAvoidwinding size and fitting complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the traditional single-stage winding into multiple independent elementary coils (first elementary coil, second elementary coil, etc.) that can be separately manufactured, assembled, and replaced. Each elementary coil is wound on a separate former and then assembled together to form the complete winding structure, thereby reducing the complexity of fitting operations while maintaining the required electrical performance and insulation class.

Inventive Principle:
Principle #1Segmentation

2Power

If traditional single-stage cigar windings are used, then the transformer achieves required power output, but any damage to the winding requires replacement of the entire winding, increasing intervention times and costs

Engineering Contradiction:
Improvepower outputVSAvoidwinding replacement complexity
Core Design Contradiction:
PowerVSEase of repair

Solution Approach 1:

The winding is segmented into multiple independent elementary coils that are electrically connected in series or parallel. If one elementary coil becomes damaged, only that specific coil needs to be replaced rather than the entire winding, significantly reducing intervention time and costs while maintaining the required power output through the remaining functional coils.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The modular elementary coil design allows for selective replacement of only the damaged component (individual coil) while retaining and reusing the undamaged elementary coils. This approach recovers the functional value of intact components and avoids the waste and cost associated with replacing the entire winding assembly.

Inventive Principle:
Principle #34Discarding and recovering

3Reliability

If traditional continuous windings are used, then the transformer achieves required insulation levels, but the overall size of the containment case increases

Engineering Contradiction:
Improveinsulation levelVSAvoidcontainment case size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

By dividing the winding into multiple compact elementary coils with independent formers, the overall volume required for the containment case is reduced compared to a single continuous winding structure. The segmented design allows for more efficient space utilization while maintaining the required insulation levels through proper spacing and insulation materials between the elementary coils.

Inventive Principle:
Principle #1Segmentation

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

This design reduces maintenance and repair costs, allows for quicker interventions, and maintains competitive pricing by enabling the use of current technologies, addressing the bulkiness and high replacement costs of traditional transformers.

Implementation Method 1

a transformer is a static machine operating in alternating current suitable to convert the parameters of output voltage and electric current with reference to those input ones

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

two or more inductor circuits, called primary windings and secondary winding, mutually coupled each other through a common magnetic flux

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 3

dispose the power dissipated both in the ferromagnetic core, due to hysteresis and parasitic currents

Methodology Applied
Scientific EffectHysteresis: Magnetic Hysteresis

Implementation Method 4

power dissipated both in the ferromagnetic core, due to hysteresis and parasitic currents, and in the windings due to Joule effect

Methodology Applied
Scientific EffectJoule effect: Joule Heating

Data Source

PatentEP2272073B1Optimized transformer, in particular for carrying ou dielectric tests
Publication Date: 2015.04.29 S E A SOC ELETTROMECCANICA ARZIGNANESE
  • EP2272073B1 patent drawingFigure 1
  • EP2272073B1 patent drawingFigure 2
  • EP2272073B1 patent drawingFigure 3

AI summary

An optimized transformer (1), in particular for carrying out dielectric tests, comprising a containment case (2) which is placed on a support structure, a magnetic core (3) placed inside the containment case (2), a primary winding (4), coupled with the magnetic core (3) and a secondary winding (6), magnetically coupled with the primary winding (4) through the magnetic core (3). At least one between the primary winding (4) and the secondary winding (6) comprises a plurality of layers (8) facing one another, defining linear directions (Y) substantially parallel each other, each layer (8) including a plurality of elementary coils independent one from another, electrically connected each other.