Medium-Voltage Switching Pole With Bistable Vacuum Interrupter Drive
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Solution Overview
Problem
Traditional load-break switches for medium voltage electric systems face challenges in achieving high dielectric insulation and arc-quenching capabilities while minimizing environmental impact, particularly due to the limitations of sulfur hexafluoride (SF6) and the complexity of managing multiple contact arrangements.
Innovation Solution
The switching apparatus incorporates a compact and reliable design with electric poles featuring a vacuum interrupter and a bistable motion transmission mechanism. This mechanism allows for efficient movement of the movable arc contact within a vacuum chamber, enhancing arc quenching and synchronization with the movable contact, thereby improving structural compactness and operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SF6 gas is used for dielectric insulation and arc-quenching, then excellent insulation performance and arc-quenching capabilities are achieved, but environmental harm increases due to SF6 being a powerful greenhouse gas
Solution Approach 1:
The patent changes the physical state of the insulating medium from gaseous (SF6) to liquid (insulating liquid), fundamentally altering the parameter of matter state to achieve both excellent insulation performance and environmental sustainability. The liquid medium provides superior dielectric properties while being environmentally benign.
Solution Approach 2:
The patent creates an inert liquid environment that serves both as insulating medium and arc-quenching agent. The insulating liquid provides an inert atmosphere that suppresses arc formation and extinguishes arcs rapidly, replacing the harmful gaseous SF6 with a benign liquid alternative.
2Reliability
If multiple contact arrangements are used for carrying current and quenching arcs, then high-level arc-quenching capabilities are achieved, but device complexity increases due to complicated coordination requirements
Solution Approach 1:
The patent merges the functions of current-carrying contacts and arc-quenching contacts into a single integrated contact arrangement. The same contacts that carry normal operating current also serve as arc-quenching contacts when the breaker operates, eliminating the need for separate contact systems and their complex coordination.
Solution Approach 2:
The contact arrangement is designed to perform multiple functions: it carries load current during normal operation and simultaneously serves as the arc-quenching mechanism during circuit breaking. This multi-functional design simplifies the overall structure while maintaining high arc-quenching capabilities through the liquid 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
The solution achieves high-level performances in dielectric insulation and arc-quenching, ensures high reliability, and allows for easier industrial production at competitive costs, while reducing environmental impact by avoiding the use of SF6.
Implementation Method 1
a vacuum interrupter, which includes a fixed arc contact electrically connected to the first pole terminal, a movable arc contact electrically connected to the fourth fixed contact and reversibly movable along a corresponding translation axis between a coupled position with the fixed arc contact and an uncoupled position from the fixed arc contact. The vacuum interrupter further includes a vacuum chamber, in which the fixed arc contact and the movable arc contact are enclosed
Implementation Method 2
designed for quenching the electric arcs arising when the current flowing along the electric pole is interrupted
Data Source
AI summary
A switching apparatus including one or more electric poles. For each electric pole, the switching apparatus includes a first pole terminal, a second pole terminal, a ground terminal, and a plurality of fixed contacts spaced apart one from another. For each electric pole, the switching apparatus further includes a movable contact and a vacuum interrupter. The movable contact is reversibly movable about a corresponding rotation axis. The vacuum interrupter includes a movable arc contact reversibly movable along a corresponding translation axis. For each electric pole, the switching apparatus further includes a motion transmission mechanism operatively coupled to a contact shaft solidly coupled to the movable arc contact. The motion transmission mechanism is actuatable by the movable contact to cause a movement of said movable arc contact along said translation axis, when said movable contact moves about said rotation axis.