Gas Circuit Breaker Buffer Chamber and Flow Control

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Solution Overview

Problem

Conventional gas circuit breakers face issues with high-temperature gas blasts reducing cooling efficiency, degrading arc electrodes, prolonging current interruption time, increasing drive operating force, and instability in gas flow, particularly during high-speed re-closure actions.

Innovation Solution

A gas circuit breaker design that utilizes a pair of fixed arc electrodes and a trigger electrode, with a buffer chamber to accumulate hot exhaust gas and a compression puffer chamber to generate pressurized gas, preventing hot exhaust gas from entering the pressure-accumulation space until the latter half of the current interruption, ensuring a low-temperature gas blast and stable flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If hot exhaust gas is allowed to enter the pressure-accumulation space to elevate pressure, then the drive operating force is reduced, but the gas temperature increases reducing cooling efficiency

Engineering Contradiction:
Improvedrive operating forceVSAvoidgas temperature
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent divides the pressure-accumulation space into two separate chambers: a first pressure-accumulation chamber that accumulates hot exhaust gas to assist drive operation, and a second pressure-accumulation chamber that accumulates cool arc-extinguishing gas for effective arc quenching. This segmentation allows the system to benefit from both hot gas pressure assistance and cold gas cooling efficiency without the temperature compromise.

Inventive Principle:
Principle #1Segmentation

2Reliability

If hot exhaust gas is directed onto the arc discharge to extinguish the arc, then the current interruption performance is improved, but the arc electrodes are degraded by high temperature

Engineering Contradiction:
Improvecurrent interruption performanceVSAvoidelectrode degradation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a flow control valve as an intermediary device that selectively controls which gas source supplies the gas blast to the arc discharge. The valve can switch between supplying hot exhaust gas for pressure assistance and supplying cool arc-extinguishing gas for effective arc quenching with minimal electrode damage, thus mediating between the competing requirements of interruption performance and electrode protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stress or pressure

If hot exhaust gas is used to pressurize the puffer chamber, then the cooling efficiency is reduced, but the pressure buildup is enhanced

Engineering Contradiction:
Improvepuffer chamber pressureVSAvoidcooling efficiency
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The patent employs a flow control valve that performs preliminary action by pre-selecting and pre-positioning the appropriate gas source before the gas blast is directed at the arc discharge. Based on the operational phase, the valve ensures that cool arc-extinguishing gas is already prepared and positioned to supply the gas blast, thereby pre-preventing the energy loss that would occur from using hot exhaust gas during the critical arc quenching phase.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If the gas flow is increased to improve arc extinction, then the interruption performance is improved, but the gas flow becomes unstable during high-speed re-closure

Engineering Contradiction:
Improveinterruption performanceVSAvoidgas flow stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent incorporates a flow control valve that provides feedback control of the gas flow to the arc discharge. The valve responds to operational conditions and dynamically adjusts the gas supply, ensuring stable and controlled gas flow rates. This feedback mechanism maintains optimal gas flow for arc extinction while preventing flow instability during high-speed re-closure operations.

Inventive Principle:
Principle #23Feedback

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

This design enhances cooling efficiency, improves durability, reduces drive operating force, shortens current interruption time, and stabilizes gas flow, while maintaining excellent interruption performance even during high-speed re-closure actions.

Implementation Method 1

an arc discharge is generated between these arc electrodes

Methodology Applied
Scientific EffectArc discharge: Electric Arc

Implementation Method 2

hot exhaust gas generated by the heat of the arc discharge

Methodology Applied
Scientific EffectThermal energy conversion: Heating

Implementation Method 3

the volume in the puffer chamber is reduced by mutual approach of the puffer cylinder and the fixed piston, causing the arc-extinguishing gas in the chamber to be mechanically compressed

Methodology Applied
Scientific EffectMechanical compression: Compression

Implementation Method 4

directing arc-extinguishing gas onto the arc discharge to extinguish the arc

Methodology Applied
Scientific EffectHeat transfer: Convection

Data Source

PatentEP3157036B1Gas circuit breaker
Publication Date: 2019.06.12 KK TOSHIBA
  • EP3157036B1 patent drawingFigure 1A~1C
  • EP3157036B1 patent drawingFigure 2A~2C
  • EP3157036B1 patent drawingFigure 3A~3C

AI summary

A pair of fixed arc electrodes (30a), (30b) are arranged facing each other within a sealed container that is filled with arc-extinguishing gas 1. There are provided: a compression puffer chamber (12) for accumulating pressurized gas (35) that is obtained by elevating the pressure of the arc-extinguishing gas (1); and an insulated nozzle (32) that directs the pressurized gas (35) towards the arc discharge (7) from the compression puffer chamber (12). A buffer chamber (36) is provided, in which hot exhaust gas (20) generated by the heat of the arc discharge (7) is temporarily accumulated. A pressurized gas through-flow space (43) is provided, communicating with the compression puffer chamber (12) . In the pressurized gas through-flow space (43), an opening/closing section (41) prevents inflow of hot exhaust gas (20) by assuming a closed condition during the earlier half of the current interruption period, and in the latter half of the current interruption period the opening/closing section 41 is opened to allow flow of pressurized gas (35).