Closing Switch Tapered Contact Flexible Electrode Arc Extinction
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Solution Overview
Problem
Existing closing switches in switchgear fail to establish a strong, reliable, and fast electrical connection between electrodes during internal arc events, leading to potential damage from high pressures and currents within the switchgear.
Innovation Solution
An electrical short-circuiting closing switch with a movable contact having a tapered profile, housed in an insulating material, and actuated by a pyrotechnical mechanism, allowing for rapid and secure engagement between electrodes with flexible attachment, enabling a low resistance and strong connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a fast closing short-circuiting switch is used to make solid phase to ground connection within a few milliseconds, then the internal arc can be eliminated before the circuit breaker clears the fault, but the contact between electrodes may not be strong or reliable enough to handle very high currents
Solution Approach 1:
The electrode is designed with flexible attachment to the housing, allowing it to dynamically adjust its position during the closing operation. This flexibility enables the electrode to move and adapt to ensure strong, reliable contact with the movable contact, while still achieving fast closing within a few milliseconds. The dynamic adjustment resolves the contradiction between speed and contact reliability.
2Loss of time
If the movable contact is forced rapidly from open to closed position, then fast arc extinction is achieved, but the electrical connection may not be strong enough to withstand high pressures and currents
Solution Approach 1:
The flexible attachment of the electrode to the housing allows the electrode to dynamically adjust during the rapid closing operation. This enables the contact to achieve both fast closing (reducing arc duration) and strong, reliable electrical connection (withstanding high currents and pressures). The flexibility compensates for the rapid motion, ensuring adequate contact strength despite the short closing time.
3Manufacturing precision
If rigid electrodes are used, then manufacturing precision can be maintained, but tolerances must be very tight and the design becomes more complex
Solution Approach 1:
By making the electrode flexibly attached rather than rigid, the design accepts larger manufacturing tolerances. The flexible attachment compensates for dimensional variations and misalignments that would be problematic in a rigid design. This reduces the need for tight tolerances and simplifies the overall design and manufacturing process.
4Measurement precision
If optical sensors are used to detect faults, then fast detection is achieved, but the switchgear components may still be damaged by high pressure buildup during the circuit breaker opening time
Solution Approach 1:
The closing switch is designed to act before the circuit breaker opens. When optical sensors detect an internal arc fault, the closing switch rapidly makes a solid phase to ground connection, eliminating the internal arc and dissipating the short-circuit current to earth within a few milliseconds. This preliminary action prevents high pressure buildup that would otherwise occur during the 30-60 ms circuit breaker opening time, protecting switchgear components from damage.
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 enables rapid arc extinction, reducing the risk of overheating and damage by establishing a strong, low-resistance electrical connection within milliseconds, thus protecting switchgear components during internal arc events.
Implementation Method 1
an actuator arranged to force the movable contact from the open position to the closed position
Implementation Method 2
the movable contact electrically connects the first electrode and the second electrode by engaging the tapered profile with the first electrode opening and the second electrode opening
Implementation Method 3
at least one of the first electrode and the second electrode is flexibly attached to the housing
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An electrical short-circuiting closing switch (12) comprising an electrically insulating housing (14); a first electrode (16) having a tapered first electrode opening (30); a second electrode (18) having a tapered second electrode opening (32); a movable contact (46) having a tapered profile (48), the movable contact (46) being movable relative to the housing (14) along a closing axis (20) from an open position (24), in which the movable contact (46) is electrically disconnected from the second electrode (18), to a closed position (60), in which the movable contact (46) electrically connects the first electrode (16) and the second electrode (18) by engaging the tapered profile (48) with the first electrode opening (30) and the second electrode opening (32); and an actuator (52) arranged to force the movable contact (46) from the open position (24) to the closed position (60); wherein at least one of the first electrode (16) and the second electrode (18) is flexibly attached to the housing (14). A switchgear (10) comprising a closing switch (12) is also provided.