Field Control Element Layout for High-Voltage Triple-Point Stress

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Solution Overview

Problem

Medium voltage and high voltage equipment face increased dielectric stress at triple points, where conducting materials meet insulating materials with higher dielectric constants, necessitating dedicated electric shields for mechanical and electrical fixation.

Innovation Solution

A field control element, typically a spiral wire or spiral spring made of conducting material, is placed adjacent to the junction between conducting and insulating parts, encircling the conducting part to reduce dielectric stress without contacting the insulating material, and is encapsulated with an insulating medium for mechanical fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated electric shields are added to mitigate dielectric stress at triple points, then dielectric stress is reduced, but device complexity increases due to additional mechanical fixation and electrical contacting requirements

Engineering Contradiction:
Improvedielectric stress mitigationVSAvoidmechanical fixation and electrical contacting
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The field control element utilizes the existing outer surface of the first part as its mounting surface, eliminating the need for separate mechanical fixation structures. The element contacts the conducting material directly to establish electrical connection, using the device's own structure to provide both mechanical support and electrical connectivity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The outer surface of the first part serves multiple functions: it provides the structural boundary of the conducting component and simultaneously acts as the mounting surface for the field control element. This multi-functionality eliminates the need for dedicated fixation structures while maintaining both mechanical integrity and electrical connectivity.

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

2Ease of manufacture

If field control element is designed to contact insulating material for fixation, then mechanical fixation is achieved, but dielectric stress increases at the new triple point created

Engineering Contradiction:
Improvemechanical fixationVSAvoiddielectric stress
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The field control element acts as an intermediary that bridges the gap between mechanical fixation requirements and dielectric stress reduction. By contacting only the conducting material and positioning itself adjacent to (but not on) the insulating material, it provides mechanical support through the conducting surface while maintaining the electrical field control needed to reduce dielectric stress at the triple point.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The field control element is positioned with specific local precision: it contacts the outer surface of the first part (conducting material) at locations where it can provide fixation, while maintaining adjacency to the junction without contacting the second part (insulating material). This localized positioning achieves both mechanical fixation and dielectric stress mitigation simultaneously.

Inventive Principle:
Principle #3Local quality

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

The solution effectively reduces dielectric stress at triple points, preventing partial discharges and ensuring operational voltage can be maintained, while allowing for easy retrofitting and integration into existing equipment.

Implementation Method 1

The field control element is formed from a conducting material. The field control element is located in contact with an outer surface of the first part, and the field control element is located adjacent to the junction.

Methodology Applied
Scientific EffectElectric field distribution: Electric Field

Implementation Method 2

Locations where three different materials come together, so-called triple points, can show strongly increased dielectric stress, for example a connection of a conductor to a solid insulator that is surrounded by air, when the dielectric constant of the solid insulator is higher than the dielectric constant of the surrounding air.

Methodology Applied
Scientific EffectDielectric stress reduction: Dielectric Permittivity

Data Source

PatentEP4293696A1Medium voltage or high voltage equipment
Publication Date: 2023.12.20 ABB (SCHWEIZ) AG
  • EP4293696A1 patent drawingFigure 1
  • EP4293696A1 patent drawingFigure 2
  • EP4293696A1 patent drawingFigure 3~4

AI summary

The present invention relates to a medium voltage or high voltage equipment, comprising: - a first part (20); - a second part (10); - a field control element (100); wherein the first part is formed from a conducting material; wherein the second part is formed from an insulating material; wherein the first part is connected to the second part at a junction; wherein the medium voltage or high voltage equipment is configured such that the first part can be held at an operational voltage; wherein the field control element is formed from a conducting material; and wherein the field control element is located in contact with an outer surface of the first part, and wherein the field control element is located adjacent to the junction.