Gas-Insulated Switch Opening Speed Control at Arc Interruption
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Solution Overview
Problem
Conventional methods for driving movable contacts in gas insulated switches are insufficient for achieving sufficient current interrupting performance, especially when using alternative gases with low arc-extinguishing performance.
Innovation Solution
A motor-driven switch with a drive mechanism that converts rotational motion into linear motion, and a drive controller that controls the motor's rotation speed to ensure a lower moving speed of the movable contact during the opening operation, particularly at the interrupting point where the arc current is extinguished.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the conventional method for driving a movable contact is applied (high opening speed to improve productivity), then the opening speed of the movable contact is increased, but the distance between contacts required for current interruption becomes insufficient and current interrupting performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the opening speed variable rather than constant. The drive mechanism adjusts the opening speed according to the contact separation distance: high speed during initial separation to improve productivity, then reduces speed when approaching the interrupting point to ensure sufficient arc extinction distance. This dynamic speed adjustment resolves the contradiction between fast opening and reliable current interruption.
Solution Approach 2:
The patent changes the speed parameter during the opening operation. Specifically, the drive mechanism modifies the opening speed from a high initial value to a lower value near the interrupting point. This parameter change allows the system to achieve both fast overall opening (improving productivity) and sufficient slow-speed traversal through the arc extinction zone (improving reliability).
2Length of moving object
If the maximum separation distance between contacts is reduced (to enable miniaturization of gas insulated devices), then the device size is reduced, but the current interrupting capability becomes insufficient
Solution Approach 1:
The patent uses dynamic speed control to compensate for the reduced separation distance. By slowing down the movable contact during the critical phase near the interrupting point, the system allows more time for arc extinction to occur within the shorter distance. This dynamic adjustment maintains current interrupting capability despite the miniaturized contact separation distance.
Solution Approach 2:
The drive mechanism incorporates feedback control based on the contact separation distance. As the movable contact approaches the interrupting point, the system detects this position and automatically reduces the opening speed. This feedback mechanism ensures that regardless of the overall separation distance, the critical arc extinction phase always occurs at an appropriate speed for reliable current interruption.
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 approach allows for a motor-driven switch with sufficient current interrupting capability, even when the maximum separation distance between contacts is reduced, thereby enabling the miniaturization of gas insulated devices.
Implementation Method 1
a motor to drive the movable contact via a drive mechanism that converts rotational motion into linear motion
Data Source
AI summary
A switch includes a fixed contact, a movable contact, a motor to drive the movable contact via a drive mechanism that converts rotational motion into linear motion, and a drive controller to control driving of the motor. The drive controller controls a rotation speed of the motor such that during an opening operation of the switch, a moving speed of the movable contact in a part of an entire moving range of the movable contact is lower than a moving speed of the movable contact during a closing operation of the switch. The part of the entire moving range includes an interrupting point at which an arc current is extinguished.