Three-Position Vacuum Interrupter Disconnect Switch

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Solution Overview

Problem

Vacuum circuit interrupters face challenges in reliable dielectric coordination and increased breakdown risks during disconnect functions, leading to potential safety hazards and higher manufacturing complexity and costs.

Innovation Solution

A vacuum circuit interrupter design that incorporates a movable contact assembly and an operating mechanism to provide multiple positional functions, including switching, disconnection, and grounding, utilizing an insulating medium like air or SF6 to enhance dielectric performance and minimize breakdown risks, while maintaining a conventional two-position vacuum interrupter structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a three-position switching and isolating apparatus with blade contacts in SF6 gas is used to provide disconnect and grounding functions, then the disconnection and grounding capabilities are improved, but the current interruption capability deteriorates due to arcing considerations limiting it to very modest levels

Engineering Contradiction:
Improvedisconnect and grounding capabilitiesVSAvoidcurrent interruption capability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The apparatus is divided into two functional segments: a vacuum interrupter for current interruption and an isolating apparatus for disconnect and grounding. This segmentation allows each component to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vacuum interrupter and isolating apparatus are combined into a single integrated device, sharing common structural elements such as the cylindrical housing and operating mechanism, while maintaining distinct functional zones for switching and isolation.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a series combination of vacuum interrupter and disconnect switch is used to achieve reliable current interruption, then the switching function is improved, but the device complexity increases requiring separate components for each function

Engineering Contradiction:
Improvecurrent interruptionVSAvoidnumber of separate components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The vacuum interrupter and disconnect switch are merged into a single integrated device, sharing common structural elements such as the cylindrical housing, operating mechanism, and mounting structure, thereby reducing overall system complexity while maintaining reliable current interruption capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated device performs multiple functions (current interruption, disconnect, and grounding) within a single apparatus, eliminating the need for separate components and reducing system complexity.

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

3Device complexity

If prior proposals incorporate switching, disconnection, and grounding functions all in one vacuum envelope, then the device complexity is reduced, but the dielectric coordination reliability deteriorates due to finite probability of breakdown under high voltage pulses

Engineering Contradiction:
Improvesingle vacuum envelope designVSAvoiddielectric coordination
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The device separates the vacuum envelope (for current interruption) from the isolating apparatus (for disconnect and grounding), allowing each component to operate within its optimal dielectric environment and eliminating breakdown risks associated with high voltage pulses in the vacuum gap.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The isolating apparatus acts as an intermediary between the vacuum interrupter and the external circuit, providing a physical and electrical barrier that enhances dielectric coordination and prevents breakdown propagation.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Object-affected harmful factors

If arc suppression measures are implemented in three-position switching apparatus, then the safety is improved, but the manufacturing complexity and costs increase

Engineering Contradiction:
Improvearc suppressionVSAvoidmanufacturing complexity and cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The apparatus separates arc-generating functions (vacuum interrupter) from arc-sensitive functions (isolating apparatus with blade contacts), eliminating the need for complex arc suppression measures in the isolating section and simplifying manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vacuum environment, which naturally suppresses arcs during current interruption, is utilized to eliminate the need for additional arc suppression measures, thereby reducing manufacturing complexity and cost.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design improves dielectric coordination, reduces the likelihood of breakdowns, and simplifies manufacturing, providing reliable and cost-effective vacuum circuit interrupters with enhanced safety and operational efficiency.

Implementation Method 1

a vacuum envelope containing a fixed contact assembly and a movable contact assembly movable between a closed circuit position in electrical connection with the fixed contact assembly and an open circuit position spaced apart from the fixed contact assembly

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 2

utilizing an insulating medium like air or SF6 to enhance dielectric performance and minimize breakdown risks

Methodology Applied
Scientific EffectDielectric: Dielectric

Data Source

PatentEP1826791B1Three-position vacuum interrupter disconnect switch providing current interruption, disconnection and grounding
Publication Date: 2020.04.01 EATON INTELLIGENT POWER LTD
  • EP1826791B1 patent drawingFigure 1A~1E
  • EP1826791B1 patent drawingFigure 2
  • EP1826791B1 patent drawingFigure 3A~3C

AI summary

A vacuum circuit interrupter includes a line conductor, a vacuum interrupter, a load conductor, a ground conductor and an operating mechanism. The vacuum interrupter includes a fixed conductor and a vacuum envelope containing a fixed contact and a movable contact movable between a closed circuit position in electrical connection with the fixed contact and an open circuit position spaced apart from the fixed contact. The fixed conductor is outside of the vacuum envelope and is electrically connected to the fixed contact. The load conductor is electrically connected to the movable contact. The operating mechanism is structured to: open and close the fixed and movable contacts, and move the vacuum interrupter and the fixed conductor thereof between a first position wherein the fixed conductor is electrically connected to the line conductor, and a second position wherein the fixed conductor is electrically connected to the ground conductor.