Vacuum Circuit Breaker Electrode Material

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Solution Overview

Problem

Vacuum circuit breakers for capacitor banks face issues with increased operation force due to high interruption speeds and electrode surface roughening, leading to reduced withstand voltage and frequent restriking, necessitating longer gaps that increase mechanical complexity.

Innovation Solution

A vacuum circuit breaker with electrodes made from a composite material containing Cu, MoCr solid solution particles uniformly dispersed with an average size of 20 µm or smaller, and a dispersion state index of 1.0 or lower, which improves withstand voltage and current interruption performance without impairing mechanical strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the interruption speed or interruption gap length is increased to improve withstand voltage performance, then the withstand voltage between electrodes is improved, but the operation force required for switching is increased

Engineering Contradiction:
Improvewithstand voltage performanceVSAvoidoperation force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention changes the material parameters of the electrode by creating a composite structure with Cu matrix and uniformly dispersed MoCr solid solution particles. This material parameter change improves withstand voltage performance without requiring increased interruption speed or gap length, thereby avoiding the associated increase in operation force

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention uses a composite electrode material consisting of Cu phase with MoCr solid solution particles uniformly dispersed therein. This composite structure combines the high conductivity of Cu with the high melting point and arc resistance of MoCr, improving dielectric recovery characteristics and withstand voltage performance without increasing mechanical complexity or operation force

Inventive Principle:
Principle #40Composite materials

2Reliability

If the interruption speed is increased to improve withstand voltage performance, then the withstand voltage between electrodes is improved, but the device size and mechanical complexity are increased

Engineering Contradiction:
Improvewithstand voltage performanceVSAvoidmechanical complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention changes the material composition and microstructure parameters of the electrode to improve dielectric recovery characteristics. This allows reduction of interruption speed and gap length while maintaining withstand voltage performance, thereby simplifying the mechanical structure and reducing device complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite electrode material with uniformly dispersed MoCr particles in Cu matrix provides superior dielectric recovery characteristics compared to conventional materials. This enables the vacuum circuit breaker to achieve high withstand voltage performance with lower interruption speed and smaller gap length, reducing mechanical complexity

Inventive Principle:
Principle #40Composite materials

3Productivity

If frequent switching operation is performed, then the productivity is improved, but the electrode surface roughening accumulates and withstand voltage performance deteriorates

Engineering Contradiction:
Improveswitching frequencyVSAvoidwithstand voltage performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the chemical composition and microstructure parameters of the electrode material to create a composite structure that resists surface roughening. This allows frequent switching operations to be performed without accumulation of electrode degradation, maintaining withstand voltage performance even at high switching frequencies

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite electrode material combining Cu and MoCr solid solution particles provides enhanced resistance to surface roughening during frequent switching operations. The uniform dispersion of MoCr particles prevents localized degradation, allowing high productivity through frequent switching while maintaining reliable withstand voltage performance

Inventive Principle:
Principle #40Composite materials

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 reduces the interruption speed and gap length, decreasing operation force and enhancing reliability by improving dielectric recovery characteristics and reducing equipment size and manufacturing costs.

Implementation Method 1

a phase of solid solution particles uniformly dispersed in the Cu phase, the solid solution particles being formed of a solid solution of a heat resistant element selected from Mo, W, Ta, Nb, V and Zr and Cr

Methodology Applied
Scientific EffectSolid solution: Solid Solution Strengthening

Data Source

PatentEP3346480B1Vacuum circuit breaker
Publication Date: 2019.12.25 MEIDENSHA CORP
  • EP3346480B1 patent drawingFigure 1~2
  • EP3346480B1 patent drawingFigure 3(a)~3(b)
  • EP3346480B1 patent drawingFigure 4(a)~4(b)

AI summary

Disclosed is a vacuum circuit breaker (1) including a vacuum interrupter (3) accommodated in a ground tank (2) filled with insulating gas. At least one of a fixed electrode (10) and a movable electrode (11) of the vacuum interrupter (3) uses an electrode material in which particles containing a solid solution of a heat resistant element and Cr are finely and uniformly dispersed and in which Cu textures as a high conductive component are finely and uniformly dispersed. The electrode material contains 20 to 70% by weight of Cu, 1.5 to 64% by weight of Cr and 6 to 76% by weight of the heat resistant element relative to a weight of the electrode material. The particles of the solid solution in the electrode material have an average particle size of 20 µm or smaller.