Gas-Insulated Circuit Breaker Arc Extinction
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Solution Overview
Problem
Gas-insulated high or medium voltage circuit breakers face challenges with late restrikes due to heated gas flowing back to the arcing zone, reducing the dielectric strength and increasing the risk of arc re-ignition, particularly during long arcing times, which existing solutions like increasing heating or compression volumes are costly and difficult to implement.
Innovation Solution
A gas-insulated circuit breaker design featuring axially movable arcing contacts, a nozzle for arc-extinguishing gas, a diffuser, and a buffer volume with a movable enclosure that allows partial gas release to decrease the temperature of the arc-extinguishing gas, reducing the likelihood of restrikes by preventing heated gas from flowing back to the arcing zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heating or compression volume is increased to reduce the risk of late restrikes, then the reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs a movable enclosure (baffle) that dynamically adjusts the volume of the compression chamber during operation. The baffle moves to a first position during normal operation and to a second position during arc extinction to modify gas flow patterns. This dynamic adjustment allows optimization of gas compression and cooling without requiring a permanently larger, more complex compression volume, thereby resolving the contradiction between reliability and device complexity.
2Reliability
If the drive energy is increased to reduce the risk of late restrikes, then the reliability is improved, but the use of energy increases
Solution Approach 1:
The patent segments the gas flow path into distinct regions (arcing region, compression volume, heating volume, buffer volume) and introduces a movable baffle that selectively controls gas flow between these regions. This segmentation allows targeted cooling of the arcing zone using a controlled portion of the gas, rather than requiring high drive energy to cool the entire gas volume, thus reducing overall energy consumption while maintaining reliability.
3Reliability
If gas is completely retained in the buffer volume to maintain dielectric strength, then the insulating properties are improved, but the temperature of the gas increases leading to arc re-ignition
Solution Approach 1:
The patent extracts excess heated gas from the buffer volume through the movable enclosure (baffle) mechanism. During arc extinction, the baffle moves to allow heated gas to escape from the compression chamber and buffer volume, replacing it with cooler gas. This extraction process maintains the dielectric strength of the gas in the buffer volume while preventing temperature buildup that would lead to arc re-ignition, resolving the contradiction between maintaining dielectric strength and controlling temperature.
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 effectively reduces the temperature of the gas downstream of the arcing zone, decreasing the risk of arc re-ignition and maintaining a low-cost design by preventing heated gas from reheating and reducing the probability of restrikes.
Implementation Method 1
a nozzle (110) including a channel directed to the arcing region, for blowing an arc-extinguishing gas to the arcing region during the breaking operation
Implementation Method 2
a diffuser adjacent to the nozzle, for transporting the gas from the arcing region to a region downstream of the diffuser
Implementation Method 3
An enclosure (120) substantially surrounding the buffer volume (170) circumferentially... In the first state of motion during a breaking operation the through opening is blocked, as to prevent the gas from being released from the buffer volume
Data Source
AI summary
The present disclosure provides a gas-insulated high or medium voltage circuit breaker including a first arcing contact and a second arcing contact, wherein at least one of the two arcing contacts is axially movable including a first and a second state of motion along a switching axis, wherein during a breaking operation, an arc between the first arcing contact and the second arcing contact is formed in an arcing region; a nozzle including a channel directed to the arcing region, for blowing an arc-extinguishing gas to the arcing region during the breaking operation; a diffuser adjacent to the nozzle, for transporting the gas from the arcing region to a region downstream of the diffuser; a buffer volume directly downstream of the diffuser, and an enclosure substantially surrounding the buffer volume circumferentially.