Transformer Cooling Duct Layout for Uniform Oil Flow

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Solution Overview

Problem

Existing static electric induction devices face inefficiencies in cooling, particularly in power transformers, leading to increased size and energy losses due to uneven oil distribution and limited pump flow rates, which can result in excessive temperatures and reduced energy efficiency.

Innovation Solution

The introduction of a duct system with a controlled bypass mechanism in the oil guiding ring allows a controlled amount of oil to bypass the obstruction, increasing oil flow in radial ducts and reducing recirculating flows, enabling higher pump flow rates and improved cooling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If pump flow rate is increased to improve cooling, then cooling efficiency improves, but uneven oil distribution and recirculating flows worsen

Engineering Contradiction:
Improvecooling efficiencyVSAvoidoil distribution uniformity
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The oil guiding ring is segmented with multiple radial ducts that divide and redirect the oil flow into different axial ducts. This segmentation prevents recirculating flows by distributing oil evenly across multiple paths, allowing higher pump flow rates without creating uneven distribution patterns.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of allowing oil to flow directly upward in a single path, the oil guiding ring inverts the flow direction by redirecting it radially outward through multiple ducts. This inversion breaks up recirculating flow patterns and ensures uniform distribution even at high pump flow rates.

Inventive Principle:
Principle #13The other way round (Inversion)

2Volume of moving object

If transformer size is reduced, then compactness improves, but cooling performance worsens

Engineering Contradiction:
Improvetransformer sizeVSAvoidcooling performance
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The invention changes the flow distribution parameters by using an oil guiding ring with specifically designed radial and axial ducts. This parameter optimization allows compact transformer design while maintaining effective cooling through improved oil flow distribution and eliminated recirculating flows.

Inventive Principle:
Principle #35Parameter changes

3Speed

If oil velocity is increased to improve cooling, then cooling performance improves, but fluid dynamic effects causing uneven distribution amplify

Engineering Contradiction:
Improveoil velocityVSAvoidflow distribution stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The oil guiding ring segments the high-velocity oil flow into multiple radial ducts, distributing the kinetic energy across several paths. This prevents the amplification of fluid dynamic effects that would cause uneven distribution, allowing high oil velocities to be maintained while preserving flow stability.

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 solution enhances cooling efficiency, allowing for a more compact transformer design or reduced temperatures, thereby improving energy efficiency and robustness against manufacturing deviations, while preventing excessive temperatures.

Implementation Method 1

a pump configured to generate a flow of dielectric liquid through the cooling ducts

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

a cooler configured to cool the dielectric liquid

Methodology Applied
Scientific EffectHeat Exchanger: Heat Exchanger

Implementation Method 3

the heat generated by the heat-generating component during the intended operation may result from reversal of magnetism and/or from an electric resistivity of the heat-generating component

Methodology Applied
Scientific EffectThermal Conduction: Conduction (thermal)

Implementation Method 4

the flow obstruction is configured to allow a controlled amount of oil flow to bypass the flow obstruction

Methodology Applied
Scientific EffectPressure Gradient: Pressure Gradient

Data Source

PatentEP4413600B1Static electric induction device and operating method
Publication Date: 2025.01.01 HITACHI ENERGY LTD
  • EP4413600B1 patent drawingFigure 1~3
  • EP4413600B1 patent drawingFigure 4~9

AI summary

In one embodiment, the static electric induction device (1) comprises: - a heat-generating component (4) which is subject to electric induction, and - a duct system (5) configured to lead a coolant (4) along the heat-generating component (4), wherein - the duct system (5) includes a plurality of cross channels (51) and at least two longitudinal channels (52), each one of the longitudinal channels (52) is assigned to at least some of the cross channels (51) and the assigned cross channels (51) connect the respective longitudinal channels (52) with each other, and - the duct system (5) further includes at least one flow obstruction (53) located in at least one of the longitudinal channels (52), the flow obstruction (53) is configured to allow flow of the coolant through it and locally narrows a cross-section of the respective longitudinal channel (52) by at least 75%.