Dry Transformer Cooling Channels for Direct Airflow Routing

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Solution Overview

Problem

Conventional transformer cooling systems face inefficiencies due to air flowing around the outside of coils rather than through the cooling channels, requiring complex air guide plates that increase turbulence and reduce overall efficiency.

Innovation Solution

A transformer cooling system with a flow generating device connected to a heat exchanger, directing cooled air directly into the cooling channels within the winding body, eliminating the need for air guidance plates and reducing complexity and turbulence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If air guide plates are positioned in the immediate vicinity of the coils to improve flow resistance, then the flow resistance of the area outside the coils increases, but the system complexity and manufacturing work increase considerably

Engineering Contradiction:
Improveflow resistanceVSAvoidsystem complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the air guide plates from the system by redesigning the cooling channel geometry. The cooling channels are configured with optimized cross-sectional areas and positions that inherently guide the airflow through the coils without requiring additional air guide plates, thus reducing system complexity while maintaining the necessary flow resistance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies local quality by varying the cross-sectional area of cooling channels at different locations. The cooling channels have larger cross-sectional areas in regions where airflow guidance is needed and smaller areas where flow resistance should be maintained, allowing the system to achieve both airflow control and resistance management without additional components.

Inventive Principle:
Principle #3Local quality

2Stress or pressure

If air guide plates are used to improve cooling flow distribution, then the flow resistance increases, but the ventilation system operates with lower overall efficiency due to additional flow turbulence

Engineering Contradiction:
Improveflow resistanceVSAvoidventilation efficiency
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The invention removes air guide plates from the system and replaces them with optimized cooling channel geometry. The cooling channels are designed with smooth transitions and appropriate cross-sectional areas that maintain flow resistance while minimizing flow turbulence, thereby improving ventilation efficiency without requiring additional flow control components.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of adding air guide plates to control airflow, the invention inverts the approach by designing the cooling channels themselves to perform the guidance function. The cooling channel geometry is optimized to naturally direct airflow through the coils, eliminating the need for separate air guide plates and reducing flow turbulence.

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

3Productivity

If the cross-sectional area of cooling channels is increased to match the area between housing wall and coils, then more air flows through the cooling channels, but the cooling system becomes larger and less compact

Engineering Contradiction:
Improvecooling effectivenessVSAvoidhousing volume
Core Design Contradiction:
ProductivityVSVolume of stationary object

Solution Approach 1:

The invention applies local quality by varying the cross-sectional area of cooling channels at different locations along their length. The channels have larger cross-sectional areas in regions where airflow guidance is needed and smaller areas where flow resistance should be maintained, allowing the system to achieve both airflow control and compact dimensions without requiring uniformly large channels throughout.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention optimizes the three-dimensional geometry of cooling channels by considering their cross-sectional area variation along the longitudinal axis. The channels are designed with optimized dimensions in multiple directions, allowing efficient airflow guidance through the coils while maintaining a compact overall housing volume.

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

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 enhances cooling efficiency by ensuring most airflow goes through the cooling channels, reducing unnecessary heat exchange and complexity, leading to a more compact and cost-effective cooling system.

Implementation Method 1

heat exchanger adapted to dissipate heat from the housing

Methodology Applied
Scientific EffectHeat dissipation: Thermal Radiation

Implementation Method 2

flow generating device arranged in the housing for providing a cooling flow in the cooling channel

Methodology Applied
Scientific EffectForced convection: Forced Convection

Data Source

PatentEP3888105B1Transformer cooling system and transformer installation
Publication Date: 2024.06.12 HITACHI ENERGY LTD
  • EP3888105B1 patent drawingFigure 1
  • EP3888105B1 patent drawingFigure 2a~2b
  • EP3888105B1 patent drawingFigure 3~4

AI summary

A transformer cooling system (100) is described. The transformer cooling system (100) includes a dry transformer (1) and a housing (50) for the dry transformer. The dry transformer includes a core (10) including a leg (11). Additionally, the dry transformer includes a winding body (14) arranged around the leg (11). Further, a cooling channel (25) extending in a direction of a longitudinal axis of the winding body (14) is provided. Additionally, the transformer cooling system (100) includes a heat exchanger (60) adapted to dissipate heat from the housing (50). Further, the transformer cooling system (100) includes a flow generating device (30) arranged in the housing (50) for providing a cooling flow in the cooling channel (25). The flow generating device (30) is connected to the heat exchanger (60).