Coaxial Pole Switching Assembly for High-Voltage DC Arc Interruption
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Solution Overview
Problem
Existing electromechanical switching apparatuses for electric grids, particularly DC grids, face challenges in providing satisfactory interruption ratings, especially at high voltages, leading to prolonged electric arcs and safety concerns due to their inefficiency in interrupting DC currents.
Innovation Solution
A switching apparatus with electric poles featuring a fixed contact assembly, a movable contact assembly with a trip mechanism, and an actuation member, which allows for efficient switching and arc quenching through a kinematic chain and insulating portions, enabling effective interruption of DC currents at high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromechanical switching apparatuses are used for DC electric grids, then galvanic isolation between disconnected grid portions is ensured and they are relatively cheap to realize, but they do not provide satisfactory interruption ratings and have long opening times when interrupting DC currents at high voltages
Solution Approach 1:
The patent extracts the movable contact assembly from the traditional electromechanical structure and positions it to hang laterally relative to the fixed contact member. This extraction allows for a more optimized arc quenching path and faster separation, directly addressing the long opening time issue while maintaining the galvanic isolation function
Solution Approach 2:
The patent introduces an arc quenching medium as an intermediary between the fixed and movable contact members. This mediator rapidly extinguishes the electric arc during interruption, enabling satisfactory interruption ratings at high voltages without extending the opening time, thus resolving the contradiction between reliability and duration
2Ease of manufacture
If electromechanical switching apparatuses are used, then they are relatively cheap to realize at industrial level, but their opening time is quite long which is dangerous as electrical components can potentially feed an undergoing electric fault
Solution Approach 1:
The patent implements a trip mechanism that enables dynamic and rapid transition of the movable contact assembly from coupled to uncoupled position. This dynamic mechanism achieves fast opening times to prevent fed faults, while the overall design remains compatible with industrial manufacturing processes and cost constraints
3Ease of operation
If a compact structure is desired for the switching apparatus, then ease of installation is improved, but device complexity may increase
Solution Approach 1:
The patent merges the trip mechanism, movable contact assembly, and arc quenching components into a compact integrated unit. This merging reduces the overall footprint and simplifies installation while maintaining the necessary functional complexity for high-voltage DC interruption capabilities
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 provides improved interruption ratings, efficient arc quenching, and a compact, cost-effective design suitable for industrial manufacturing, addressing the inefficiencies of traditional switching apparatuses in high-voltage DC grids.
Implementation Method 1
an actuation member (7) accommodated in the internal volume of said electric pole and formed by an electrically insulating hollow tubular element arranged coaxially and externally relative to said fixed contact member, so that said fixed contact member passes through said actuation member along said longitudinal axis. Said actuation member is slidingly movable along said fixed contact member.
Data Source
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AI summary
A switching apparatus for low or medium voltage electric grids, which comprises one or more electric poles. Each electric pole comprises: - an outer casing made of electrically insulating material and defining an internal volume of said electric pole; - a fixed contact assembly accommodated in the internal volume of said electric pole and comprising a fixed contact member formed by an electrically conductive tubular element extending along a longitudinal axis of said electric pole; - at least a movable contact assembly accommodated in the internal volume of said electric pole and hanging laterally relative to said fixed contact member; - an actuation member accommodated in the internal volume of said electric pole and formed by an electrically insulating hollow tubular element arranged coaxially and externally relative to said fixed contact member, so that said fixed contact member passes through said actuation member along said longitudinal axis. Said actuation member is slidingly movable along said fixed contact member. In particular, said actuation member is reversibly movable between a first actuation position and a second actuation position by sliding along said fixed contact member. When moving between said first and second actuation positions, said actuation member transiently couples to each trip mechanism to actuate said trip mechanism.