High-Voltage Switch Snap-Action Mechanism Arc Control

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Solution Overview

Problem

High-voltage electrical switches face challenges in safely disconnecting and reconnecting without causing arcing damage to commutation contact elements and housings, as existing solutions do not effectively manage the high current densities and potential for self-sustaining arcs during opening and closing operations.

Innovation Solution

A switch design featuring a snap connection mechanism between commutation contact elements, where an elastic element and stop mechanisms work together to control the movement, allowing for a controlled arc formation between primary contacts to protect secondary contacts from wear and damage, while ensuring rapid disconnection and reduced arc occurrence.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the opening speed of commutation contact elements is increased, then the risk of arcing is reduced, but the complexity of the switching mechanism increases

Engineering Contradiction:
Improvearc riskVSAvoidswitching mechanism complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent employs a dynamic snap-fit connection mechanism that transitions from a stable closed position to a rapid open position. The commutation contact elements utilize an elastic element that stores energy during closing and releases it during opening, creating a dynamic two-speed motion profile that increases opening speed while managing mechanical complexity through controlled energy release

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The switching mechanism is divided into distinct functional components: the snap-fit connection system with elastic elements, the stop mechanisms defining travel limits, and the commutation contact elements. This segmentation allows each component to be optimized independently for its specific function while contributing to the overall rapid opening capability

Inventive Principle:
Principle #1Segmentation

2Productivity

If the snap connection is used to increase opening speed, then arc formation is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveopening speedVSAvoidsnap connection precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent utilizes parameter changes in the elastic element's mechanical properties to achieve rapid opening. By carefully selecting the elastic element's stiffness, pre-compression force, and engagement geometry, the system achieves high opening speed without requiring extremely tight manufacturing tolerances on the snap-fit connection features themselves

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The elastic element acts as a cushioning mechanism that pre-stores energy during the closing operation. This beforehand energy storage allows the commutation contact elements to be held firmly in the closed position while preparing the system for rapid release, reducing the need for high-precision control during the actual opening transition

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Loss of time

If the first contact is moved rapidly to open position, then the switch operation time is reduced, but the force required to overcome the snap connection increases

Engineering Contradiction:
Improveswitch operation timeVSAvoidopening force
Core Design Contradiction:
Loss of timeVSForce

Solution Approach 1:

The opening operation utilizes a periodic action pattern through the elastic element's energy release cycle. The snap-fit connection creates a natural two-phase motion: a slow approach phase where force builds up, followed by a rapid release phase where stored elastic energy drives the commutation contact elements open. This periodic action reduces peak force requirements compared to continuous high-force actuation

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The elastic element provides self-service by automatically converting stored potential energy into kinetic energy during the opening operation. Once triggered, the snap-fit mechanism uses its own stored energy to drive the rapid opening motion, reducing the external force needed from the actuating mechanism and minimizing overall switch operation time

Inventive Principle:
Principle #25Self-service

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 enhances the speed of opening commutation contact elements, reduces the risk of arc formation during both opening and closing, thereby minimizing damage to the switch components and enabling more compact high-voltage switchgear designs.

Implementation Method 1

the elastic element biases the first commutation contact element towards the open commutation contact element position

Methodology Applied
Scientific EffectElastic element biasing: Elasticity

Implementation Method 2

The first and second commutation contact elements are designed to form a snap-fit connection with each other in the closed position

Methodology Applied
Scientific EffectSnap-fit connection: Mechanical Fastener

Implementation Method 3

During the opening and closing of an electrical switch, an arc, i.e., a self-sustaining gas discharge with a sufficiently high electrical potential difference to maintain the required high current density through impact ionization, can occur between commutation contact elements

Methodology Applied
Scientific EffectArc formation: Electric Arc

Data Source

PatentEP3504726B1Switch and method for disconnecting a switch
Publication Date: 2020.12.02 ABB POWER GRIDS SWITZERLAND AG
  • EP3504726B1 patent drawingFigure 1
  • EP3504726B1 patent drawingFigure 2
  • EP3504726B1 patent drawingFigure 3

AI summary

The switch (100) comprises a housing (105), a first contact arrangement (110) having a first commutation contact element (112) and a first contact (114), a second contact arrangement (120) having a second commutation contact element (122) and a second contact (124), and also a nominal contact arrangement (117, 115, 124). The first commutation contact element (112) and the second commutation contact element (122) form a snap-action connection with one another in the closed position of the commutation contact element. When the switch (100) is closed, a distance between the first contact (114) and the second contact (124) is smaller than a distance between the first commutation contact element (112) and the second commutation contact element (122) in the direction of the axis (A).