Ground Switch Interlock for Vacuum Circuit Breaker Safety
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Solution Overview
Problem
Vacuum circuit breakers pose a risk of ground faults when the ground switch is at a ground position, as applying power to the circuit can cause damage due to the inability to prevent the circuit breaker main body from being driven to the ON position during maintenance, necessitating an interlock mechanism to prohibit drawing-in or drawing-out operations.
Innovation Solution
A ground switch interlock apparatus that includes a drive spindle, a movable plate, a first interlock plate, and a second interlock plate, which work together to prevent the manipulation handle from connecting to the drive spindle when the ground switch is at a ground position, thereby preventing the circuit breaker main body from being drawn in or out.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ground switch is at a ground position, then the secondary-side charged current can be discharged, but the circuit breaker main body can still be driven to the ON position causing ground faults
Solution Approach 1:
The interlock apparatus applies preliminary anti-action by preventing the manipulation handle from being connected to the drive spindle when the ground switch is at the ground position. The first interlock plate blocks the connection between the manipulation handle and drive spindle, and the second interlock plate further prevents any attempt to drive the circuit breaker main body, thereby counteracting the potential harmful action before it can occur.
Solution Approach 2:
The interlock apparatus acts as an intermediary mechanism between the ground switch and the circuit breaker main body drive mechanism. The first and second interlock plates serve as mediators that detect the ground switch position and automatically prevent the drive mechanism from operating, ensuring that no direct control signal can reach the drive spindle when the ground switch is engaged.
2Ease of operation
If the manipulation handle can be freely connected to the drive spindle, then the circuit breaker main body can be easily moved, but the interlock mechanism cannot be implemented
Solution Approach 1:
The interlock apparatus employs dynamic elements that automatically adjust their state based on the ground switch position. The first interlock plate is movable to block or allow the connection between the manipulation handle and drive spindle, and the second interlock plate is movable to prevent or permit driving attempts. This dynamic configuration allows the system to be easy to operate when safe, but automatically becomes restrictive when the ground switch is engaged, maintaining both ease of operation and reliability.
Data Source
AI summary
Provided herein is an interlock apparatus for preventing the drawing-in or drawing-out of a vacuum circuit breaker main body in interlock with the ground operation of a ground switch in a vacuum circuit breaker, and the ground switch interlock apparatus of the vacuum circuit breaker comprising: a drive spindle; a movable plate movable to a manipulation handle connection allowance position or a manipulation handle connection prohibition position; a first interlock plate that moves the movable plate to the manipulation handle connection allowance position or the manipulation handle connection prohibition position; and a second interlock plate to be moved to a position for locking the first interlock plate at the manipulation handle connection prohibition position when the ground switch is at a ground position and a position for releasing from the restraint of the first interlock plate when the ground switch is not at the ground position.