High Voltage Disconnector Switch Diode Arcing Contact

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Solution Overview

Problem

High voltage disconnector switches face challenges in reducing arcing time and contact erosion during increased bus transfer current and voltage ratings, especially in air-insulated applications, where existing solutions do not adequately address the need for faster switching and higher ratings.

Innovation Solution

A high voltage disconnector switch design incorporating a power diode in the arcing current path, which clips one polarity of the current flow during opening, and a spring mechanism to push the movable arcing contact onto the fixed arcing contact, allowing the insulation gas to recover from arc plasma, thereby reducing arcing time and contact erosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If the opening speed of arcing contacts is increased to reduce arcing time, then contact erosion is reduced, but device complexity increases due to the need for snapping contact systems

Engineering Contradiction:
Improvearcing timeVSAvoidcontact system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The harmful arc phenomenon is extracted and redirected to dedicated arcing contacts that are spatially separated from the main current-carrying contacts. The arc is confined to a specific region between arcing contacts, preventing damage to main contacts while maintaining simple contact geometry without complex snapping mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Dedicated arcing contacts act as intermediary elements that absorb the harmful arc effects. These intermediate contacts are specifically designed to handle the arc discharge, protecting the main current-carrying contacts from erosion while maintaining a simple mechanical structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If bus transfer current and voltage ratings are increased to meet higher energy demands, then switching capability is improved, but arcing time increases due to slower opening speed

Engineering Contradiction:
Improvebus transfer current ratingVSAvoidarcing time
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

The contact system is segmented into functionally distinct components: main current-carrying contacts for power transmission and dedicated arcing contacts for arc management. This segmentation allows the system to handle high power ratings while the arcing contacts specifically address the arc duration issue through their geometric design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different parts of the contact system have optimized local geometries for their specific functions. The arcing contacts feature specific geometric configurations that promote rapid arc extinction, while the main contacts are optimized for high current carrying capacity. This local optimization allows high power ratings without proportionally increased arcing time.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If moving contact speed is increased to reduce arcing time, then contact erosion decreases, but manufacturing precision requirements increase

Engineering Contradiction:
Improvecontact erosionVSAvoidcontact alignment precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The arc phenomenon is extracted and isolated to dedicated arcing contacts with specific geometric designs that inherently promote rapid arc extinction. This extraction eliminates the need for high-speed moving contacts, as the arc is naturally confined and extinguished quickly by the arcing contact geometry, reducing manufacturing precision requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If simple contact geometry is used to reduce manufacturing complexity, then device complexity is reduced, but arc extinction capability deteriorates

Engineering Contradiction:
Improvecontact system complexityVSAvoidarc extinction time
Core Design Contradiction:
Device complexityVSDuration of action of moving object

Solution Approach 1:

The contact system is divided into main contacts with simple geometry for easy manufacturing and dedicated arcing contacts with specialized geometries for arc extinction. This segmentation allows simple overall structure while the arcing contacts specifically address arc extinction through their geometric design, achieving both simplicity and effectiveness.

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

The solution enables operation with higher current and voltage ratings by minimizing arcing time to a single current loop and reducing contact erosion, enhancing the switch's performance and reliability.

Implementation Method 1

a power diode arranged between the fixed first main contact and the fixed arcing contact and/or between the fixed arcing contact and the movable arcing contact

Methodology Applied
Scientific EffectPower diode current clipping: Diode

Implementation Method 2

comprising a spring arranged within the opening of the movable main contact and configured for pushing, in the closed position, the movable arcing contact onto and thereby electrically contacting the fixed arcing contact

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

In a current free period a dielectric strength of an insulation gas, for example SF6 or an alternative, can recover from the arc plasma

Methodology Applied
Scientific EffectArc plasma: Plasma

Implementation Method 4

During the opening and closing of an electric switch, an arc can be generated, i.e. a self-sustained gas discharge which has a sufficiently high electrical potential difference for the maintenance, by impulse ionization, of the requisite high current density

Methodology Applied
Scientific EffectElectric arc: Electric Arc

Data Source

PatentEP4227971A1High voltage disconnector switch
Publication Date: 2023.08.16 HITACHI ENERGY LTD
  • EP4227971A1 patent drawingFigure 1a~1c
  • EP4227971A1 patent drawingFigure 2a~2c
  • EP4227971A1 patent drawingFigure 3a~3c

AI summary

The invention relates to a high voltage disconnector switch comprising a fixed first main contact (1) comprising at least one first contact element (4a), a fixed second main contact (2) comprising at least one second contact element (4b) and axially extending in extension of the fixed first main contact (1), a movable main contact (3) comprising an axially extending opening, arranged movably between an open position and a closed position and axially in parallel to the fixed first main contact (1) and the second main contact (2), whereby the movable main contact (3) is electrically connected in both positions via the at least one second contact element (4b) with the fixed second main contact (2) and only in the closed position via the at least one first contact element (4a) with the fixed first main contact (1), a fixed arcing contact (5) connected with a first end to the fixed first main contact (1), extending axially parallel to the movable main contact (3) and arranged for being encompassed on a second opposite end by the opening of the movable main contact (3), a movable arcing contact (6) movably arranged within the opening of the movable main contact (3), electrically connected via at least one third contact element (4c) to the movable main contact (3) and comprising a spring (8) arranged within the opening of the movable main contact (3) and configured for pushing, in the closed position, the movable arcing contact (6) onto and thereby electrically contacting the fixed arcing contact (5), and a power diode (7) arranged between the fixed first main contact (1) and the fixed arcing contact (5) and/or between the fixed arcing contact (5) and the movable arcing contact (6).