Transformer Accessory Tank Layout to Block Hot Dielectric Fluid

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Solution Overview

Problem

Static electric induction devices, such as transformers, experience overheating issues due to heat generation, which can degrade insulation materials and reduce the lifespan of accessories, and existing solutions do not effectively address the challenge of using temperature-sensitive accessories in high-temperature environments while minimizing weight and volume.

Innovation Solution

A static electric induction arrangement with a separate accessory tank connected via a fluid connection to the main tank, featuring a heat exchanger with an inlet located at or above the fluid connection's upper portion, preventing hot dielectric fluid from entering the accessory tank, and utilizing high-temperature dielectric fluids for passive convection cooling, along with additional heat barriers and fins for enhanced cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If accessories are placed directly in the main tank with hot dielectric fluid, then the cooling effect is maximized, but the accessories overheat and their insulation material degrades

Engineering Contradiction:
Improvetemperature of dielectric fluidVSAvoidreliability of accessory
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent divides the system into two separate tanks: a main tank for the static electric induction device and an accessory tank for temperature-sensitive accessories. This segmentation allows different temperature conditions in each tank, enabling the main tank to operate at higher temperatures while the accessory tank maintains lower temperatures suitable for sensitive components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a heat exchanger as an intermediary between the main tank and accessory tank. The heat exchanger transfers heat from the dielectric fluid in the main tank to cool the dielectric fluid in the accessory tank, enabling thermal coupling without direct fluid mixing. This allows temperature-sensitive accessories to be cooled indirectly while the main tank operates at higher temperatures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If a separate accessory tank is introduced with heat exchanger and fluid connection, then temperature-sensitive accessories are protected, but the device complexity increases

Engineering Contradiction:
Improvereliability of accessoryVSAvoidcomplexity of cooling system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs natural convection for dielectric fluid circulation within both tanks. The fluid circulates automatically based on temperature-driven density differences, eliminating the need for external pumps or complex active cooling control systems. This self-service approach reduces device complexity while maintaining effective cooling.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the cooling function with the dielectric fluid system itself. The same dielectric fluid serves both as the insulation medium and the cooling medium in both tanks, eliminating the need for separate cooling circuits. The heat exchanger integrates thermal management into the existing fluid system, reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If the inlet of heat exchanger is located below the fluid connection, then hot dielectric fluid can flow freely, but hot fluid enters the accessory tank causing overheating

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidtemperature in accessory tank
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent positions the heat exchanger inlet at a higher vertical level than the fluid connection between tanks. This vertical arrangement exploits gravitational and buoyancy effects: cooler, denser fluid from the accessory tank flows down to the heat exchanger inlet, while heated fluid rises naturally. This dimensional positioning prevents hot fluid from entering the accessory tank while maintaining effective heat exchange.

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

Solution Approach 2:

The patent replaces active pumping mechanisms with passive thermal convection and buoyancy-driven flow. The inlet positioning leverages natural fluid dynamics where heated fluid rises and cooler fluid sinks, creating automatic circulation without mechanical intervention. This substitution simplifies the system while achieving the desired temperature control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 allows the use of temperature-sensitive accessories in high-temperature environments, reduces the risk of accessory failure, and achieves a more compact, lighter-weight static electric induction device by maintaining accessories at lower temperatures, thus extending their lifespan and improving the arrangement's reliability.

Implementation Method 1

utilizing high-temperature dielectric fluids for passive convection cooling

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

heat exchanger connected to the static electric induction device tank

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

utilizing high-temperature dielectric fluids for passive convection cooling

Methodology Applied
Scientific EffectPassive convection: Free Convection

Data Source

PatentEP3940727B1A static electric induction arrangement
Publication Date: 2024.09.04 HITACHI ENERGY LTD
  • EP3940727B1 patent drawingFigure 1
  • EP3940727B1 patent drawingFigure 2
  • EP3940727B1 patent drawingFigure 3

AI summary

The present disclosure relates to a static electric induction arrangement (1) comprising: a static electric induction device (2) arranged in a static electric induction device tank (3); an accessory tank comprising at least one opening (26) configured to receive an accessory (15) therein; the static electric induction device tank (3) and the accessory tank (5) are intended to be filled with dielectric fluid and are connected via a fluid connection (7), an upper portion (71) of a cross section of the fluid connection (7), is located at a first height (H), the arrangement comprises a heat exchanger (12) connected to the device tank (3), the device tank (3) comprises an outlet (13) that is arranged to lead the dielectric fluid (4) to the heat exchanger (12) and an inlet (14) that is arranged to return the dielectric fluid (4) from the heat exchanger (12) to the static electric induction device tank (3), the inlet (14) is located at the same height or vertically above the first height (H).