Barrier Arrangement Radial Oil Path High Voltage Insulation

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Solution Overview

Problem

High-voltage transformers and choke coils face challenges in achieving sufficient dielectric strength, particularly in high-voltage direct current applications, due to increasing voltage levels, which require more precise electrical insulation and reduced oil gaps between the cable bushing and barrier systems.

Innovation Solution

The introduction of an additional radial oil path formed by at least one almost rotationally symmetrical barrier element between the line bushing and the barrier arrangement, allowing for radial and axial oil circulation, increases the permissible electric field strengths without altering the existing design of current ducts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the voltage level is increased to meet high-voltage network requirements, then the power transmission capability is improved, but the dielectric strength requirement becomes more difficult to achieve

Engineering Contradiction:
Improvepower transmission capabilityVSAvoiddielectric strength
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The barrier system is divided into multiple individual barriers (15-25 barriers) arranged in sequence, with each barrier creating a separate oil gap. This segmentation allows the total insulation path to be distributed across multiple controlled intervals, maintaining dielectric strength at higher voltage levels without requiring a single large oil gap that would be impractical.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a single-dimensional insulation approach to a multi-dimensional barrier arrangement. Barriers are positioned at different radial distances (15-25 barriers at definable distances) from the cable bushing, creating a three-dimensional insulation structure that effectively manages electric field distribution at high voltages up to 800kV.

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

2Reliability

If the oil gap between the cable bushing and barrier arrangement is reduced to increase dielectric strength, then the electrical insulation is improved, but the cooling efficiency deteriorates

Engineering Contradiction:
Improveelectrical insulationVSAvoidcooling efficiency
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The insulation system is segmented into multiple barriers with oil gaps between them, rather than using a single large oil gap. This allows the total insulation distance to be maintained while distributing the space across multiple intervals, preserving cooling pathways while achieving the required dielectric strength for high-voltage applications.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The barrier elements act as intermediaries between the cable bushing and the outer barrier arrangement. These barriers create controlled oil gaps that maintain electrical insulation while allowing transformer oil to circulate through the defined channels, thus preserving cooling efficiency even as insulation requirements increase with higher voltages.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the number of barriers is increased to meet insulation requirements, then the dielectric strength is improved, but the device complexity increases

Engineering Contradiction:
Improvedielectric strengthVSAvoidbarrier system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each barrier element serves multiple functions: it provides electrical insulation, defines oil circulation channels for cooling, and contributes to the mechanical structure of the barrier system. This multi-functionality allows 15-25 barriers to be arranged systematically without proportionally increasing overall system complexity, as each component performs several critical roles simultaneously.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention manages complexity by standardizing barrier parameters (thickness 3-5mm, diameters up to 1,500mm, lengths up to 3,000mm) and arranging them in a systematic pattern at definable distances from the cable bushing. This parameter standardization allows for scalable deployment of 15-25 barriers to meet different voltage requirements while maintaining manageable system complexity through consistent design rules.

Inventive Principle:
Principle #35Parameter changes

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 the dielectric strength between the line bushing and the barrier arrangement, enabling operation at higher voltages, such as over 500kV, by subdividing oil gaps and optimizing the arrangement of barrier elements, thus supporting reliable electrical insulation and cooling.

Implementation Method 1

with a cooling medium, in particular transformer oil, circulating within the barrier system for electrical insulation and cooling

Methodology Applied
Scientific EffectOil circulation: Convection

Implementation Method 2

electrical shielding between the electrical line of the high-voltage network and the components of the electrical system is only possible using a multi-part barrier system

Methodology Applied
Scientific EffectElectrical shielding: Electric Field

Implementation Method 3

the shielding electrode has paper insulation, which ensures appropriate electrical shielding

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Data Source

PatentEP2351056B1Barrier arrangement for a cable duct
Publication Date: 2019.12.25 SIEMENS AG
  • EP2351056B1 patent drawingFigure 1
  • EP2351056B1 patent drawingFigure 2
  • EP2351056B1 patent drawingFigure 3

AI summary

The invention relates to a barrier arrangement (2) for a cable duct (3) having barriers (7a, 7b, 7c) arranged next to each other and disposed at prescribed distances from each other. By introducing an additional barrier element (4a) between the cable duct and the barrier arrangement, an additional radial oil segment is created, so that the permissible field strengths within the oil can be thereby increased. This is advantageous, particularly when using the barrier arrangement for high voltages above 500 kV. Simultaneously, nearly identical barrier arrangements can be used for very different operating voltages, and need to be adjusted only with regard to the barrier elements and the constant spacing to the cable duct.