High Pressure Bushing Dual-Surface Cooling for Rotating Electrical Machines

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Solution Overview

Problem

Current high pressure bushings in rotating electrical machines, such as turbine generators, suffer from inadequate cooling efficiency due to the limited use of the inner circumferential surface of the hollow connecting conductor, leading to heat generation issues and potential gas leakage, as they rely mainly on the inner surface for cooling and require either reduced current flow or increased conductor size to enhance cooling.

Innovation Solution

The design incorporates a hollow connecting conductor with communicating holes on both inner and outer sides, combined with a gas circulation pipe and insulating cylinder, allowing cooling gas to flow through both surfaces, including the outer circumference, and utilizing baffle plates and reflux holes to optimize gas distribution and reduce pressure loss, thereby enhancing cooling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If cooling is performed using only the inner circumferential surface of the hollow connecting conductor, then the structure is simple, but the cooling efficiency is insufficient

Engineering Contradiction:
Improvestructural simplicityVSAvoidcooling efficiency
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The invention transitions from single-surface cooling (inner circumferential surface only) to dual-surface cooling by adding the outer circumferential surface as an additional cooling dimension. This is achieved by providing cooling passages on both the inner and outer surfaces of the hollow connecting conductor, allowing cooling gas to flow through both surfaces simultaneously, thereby significantly improving cooling efficiency without complicating the overall structure

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

2Temperature

If the current value is reduced to improve cooling, then heat generation decreases, but the electric output capability is reduced

Engineering Contradiction:
Improveheat generationVSAvoidelectric output capability
Core Design Contradiction:
TemperatureVSPower

Solution Approach 1:

The invention extracts the heat dissipation function from the limited inner surface cooling and adds a separate outer surface cooling system. By providing cooling passages on the outer circumferential surface of the hollow connecting conductor, the system can dissipate heat more effectively, allowing higher current values to be sustained without excessive heat generation, thereby maintaining electric output capability while improving cooling

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If the hollow connecting conductor is enlarged to improve cooling, then cooling surface area increases, but the device size increases

Engineering Contradiction:
Improvecooling surface areaVSAvoiddevice size
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The invention segments the cooling function into two independent cooling systems: inner circumferential surface cooling and outer circumferential surface cooling. By dividing the cooling task across two surfaces, the system achieves increased total cooling surface area without needing to enlarge the hollow connecting conductor's overall dimensions, thus maintaining compact device size while improving cooling efficiency

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 configuration effectively cools both surfaces of the high pressure bushing and its components, improving overall cooling efficiency without the need for reduced current flow or enlarged conductor sizes, while minimizing heat generation and gas leakage risks.

Implementation Method 1

the cooling gas introduced from inside the device is used for cooling

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

the high pressure bushing generates heat by a large current flowing in the hollow connecting conductor

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP2621063B1High pressure bushing of rotating electrical machine and rotating electrical machine
Publication Date: 2019.04.03 KK TOSHIBA
  • EP2621063B1 patent drawingFigure 1
  • EP2621063B1 patent drawingFigure 2~3
  • EP2621063B1 patent drawingFigure 4~5

AI summary

According to one embodiment, there is provided a high pressure bushing arranged through by penetrating a stator frame (7) of a rotating electrical machine in which a cooling gas is sealed. The high pressure bushing includes a hollow connecting conductor (11) that has a machine outer side end portion (11B) sealed, and introduces the cooling gas within the machine from a machine inner side end portion (11A), a gas circulation pipe (12) that is arranged in an inner circumference side of the hollow connecting conductor (11) with a first gap (G1), and discharges the cooling gas toward a machine inner side, and an insulating cylinder (13) that is arranged in an outer circumference side of the hollow connecting conductor (11) with a second gap (G2), and electrically insulates the hollow connecting conductor (11) and the stator frame (7), wherein at least a communicating hole (11a, 11b, or 11c) is provided in the hollow connecting conductor (11) and at least a reflux hole (12a, 12b, or 12c) is provided in the gas circulation pipe (12), such that the cooling gas flows in both of the first gap (G1) and the second gap (G2), passes through an inner side of the gas circulation pipe (12), and is discharged to the machine inner side.