Three Phase Earthing Switch with Adjustable Earth Contacts

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Solution Overview

Problem

Current three-phase earthing switches in medium voltage switchgear require improvements in performance, cost reduction, and complexity reduction while ensuring safe operation and earth potential interconnection.

Innovation Solution

A three-phase earthing switch design featuring a base unit with rotating connectors and adjustable earth contacts, allowing for two operational modes with freely adjustable fixation points, and utilizing exchangeable interconnecting bars and a spring mechanism for precise positioning and contact engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional three-phase earthing switch design is used, then structural stability is maintained, but device complexity and cost increase

Engineering Contradiction:
Improveearthing switch complexityVSAvoidearthing switch reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The earthing switch is divided into three independent base units, each handling one phase. Each base unit contains a connector that can independently engage with earth contacts. This segmentation reduces overall device complexity while maintaining reliability through independent phase operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The three base units are designed with identical structures that can perform the same earthing function for different phases. This universal design simplifies manufacturing and reduces complexity while ensuring consistent reliable performance across all phases.

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

2Adaptability or versatility

If fixed spacing design is used, then manufacturing precision is improved, but adaptability decreases

Engineering Contradiction:
Improveearthing switch adaptabilityVSAvoidcontact engagement precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The earth contacts are designed with adjustable positioning mechanisms that allow the spacing between base units and earth contacts to be modified. This dynamic adjustability enables the earthing switch to adapt to different installation requirements while maintaining precise contact engagement through adjustable fixation points.

Inventive Principle:
Principle #15Dynamics

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 enhances performance, reduces complexity, and lowers costs by enabling adjustable configurations for precise earth contact engagement, ensuring safe and efficient operation while maintaining mechanical independence and ease of assembly.

Implementation Method 1

The earthing switch has an exchangeable spring that is held by the at least one base unit. Activation of the spring is configured to transition the earthing switch from the first mode of operation to the second mode of operation.

Methodology Applied
Scientific EffectSpring mechanism: Spring

Data Source

PatentEP3594982A1A three phase earthing switch
Publication Date: 2020.01.15 ABB (SCHWEIZ) AG
  • EP3594982A1 patent drawingFigure 1~2b
  • EP3594982A1 patent drawingFigure 3
  • EP3594982A1 patent drawingFigure 4

AI summary

The present invention relates to a three phase earthing switch (50). The earthing switch has at least one base unit (1), three connectors (4), and three earth contacts (12). The at least one base unit is configured to hold the three connectors. A first distil end of each of the three connectors is configured to rotate with respect to the at least one base unit. A second distil end of each of the three connectors comprises a contact knife. The three earth contacts are configured to be mounted at three locations that are mechanically independent from and spaced from the at least one base unit. In a first mode of operation the three connectors are not in contact with the three earth contacts. In a second mode of operation the three connectors are moved such that the three contact knifes are in contact with the three earth contacts.