Vacuum Switch Chamber in Parallel Branch for Power Line Interrupters
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Solution Overview
Problem
The use of vacuum switch chambers in power line current interrupters is economically unviable due to material and dimensional requirements needed to withstand electrical and dielectric demands, such as lightning strikes, and the drawbacks of sulfur hexafluoride gas include toxicity and greenhouse gas contributions.
Innovation Solution
A power line current interrupter design featuring a vacuum switch chamber connected in a parallel branch rather than the main power line, where the disconnector and movable part arrangement allows the vacuum switch chamber to remain at rest during normal operation, reducing the need for stringent features and utilizing the disconnector's movement to establish current flow for opening the power line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum switch chambers are used in the main power line to interrupt current, then arc quenching effectiveness is improved, but material and dimensional requirements increase significantly, making the device economically unviable
Solution Approach 1:
The circuit is segmented into a main power line and a parallel branch. The vacuum switch chamber is placed in the branch rather than the main line, so it only needs to handle transient currents during switching operations, not the full continuous load current. This segmentation reduces the electrical and dielectric demands on the vacuum chamber, allowing smaller, more economical dimensions and materials while maintaining arc quenching effectiveness when needed.
Solution Approach 2:
The vacuum switch chamber operates periodically only during the brief moments when current transfer occurs between the disconnector and the branch, rather than continuously handling full power line current. This periodic operation reduces thermal and electrical stress on the chamber, allowing for reduced material thickness and smaller dimensions while still providing reliable arc quenching during the intermittent switching events.
2Reliability
If sulfur hexafluoride gas is used as dielectric fluid, then dielectric properties are improved, but toxic decomposition products and greenhouse gas effects occur
Solution Approach 1:
The vacuum switch chamber operates in a vacuum environment, which is inherently inert and free from atmospheric gases. This eliminates the need for sulfur hexafluoride or other dielectric gases, avoiding toxic decomposition products and greenhouse gas emissions while still providing effective arc quenching through the vacuum medium itself. The vacuum serves as both the operating environment and the arc-quenching medium.
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 makes vacuum switch chambers economically viable by reducing material and dimensional demands, allowing for effective arc quenching without the toxic and greenhouse gas issues associated with sulfur hexafluoride, while ensuring reliable current interruption and reclosure.
Implementation Method 1
a vacuum switch chamber having two switch contacts arranged for relative movement between them
Data Source
AI summary
This interrupter device includes a parallel branch (4) in which a vacuum switch chamber is connected for breaking current. The branch is inactive in normal operation, with current flowing in it only when the disconnector (2) has started its opening movement, by progressive transfer of the current from the main power line (1) to the branch (4). Since the vacuum switch (6) is generally at rest, it no longer needs to be dimensioned to satisfy stringent electrical and dielectric requirements for normal operation.