Circuit Breaker Plug Interlock for Control Line Connection Safety
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Solution Overview
Problem
Existing plug interlock devices for circuit breakers allow the circuit breaker to retract and extend without ensuring the control line plug is inserted, leading to potential accidents due to disconnection during emergency remote control scenarios.
Innovation Solution
A plug interlock device comprising a lever-type extending/retracting motion interlock assembly, a plug connector assembly, a shaft, and a blocking plate that only allows the circuit breaker to retract and extend when the control line plug is inserted, using a mechanism where the shaft rotates based on the plug connector assembly's movement, horizontally positioning the blocking plate to control the interlock assembly's movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the lever-type interlock assembly is used to allow circuit breaker retraction and extension, then the circuit breaker can be transferred between test and service positions, but the control line plug may be disconnected during movement leading to safety accidents
Solution Approach 1:
The plug interlock mechanism performs a preliminary check by requiring the control line plug to be inserted into the connector before the circuit breaker can be transferred. The blocking plate is positioned in advance to prevent lever movement unless the plug is properly connected, thereby ensuring safety before the transfer operation commences.
Solution Approach 2:
The blocking plate serves as an intermediary element between the lever-type interlock assembly and the plug connector assembly. It mediates the interaction by physically blocking the lever's movement path when the plug is not connected, and allowing movement when the plug is connected, thus enforcing the safety interlock condition.
2Reliability
If a plug interlock mechanism is added to prevent disconnection during transfer, then safety and reliability are improved, but the device complexity increases
Solution Approach 1:
The plug interlock mechanism is merged with the existing lever-type interlock assembly by integrating the blocking plate into the same structural space. The blocking plate utilizes the existing lever movement path and structural features, combining the plug connection check function with the existing transfer interlock mechanism rather than adding a completely separate system.
Solution Approach 2:
The interlock mechanism is segmented into distinct functional components: the plug connector assembly that detects plug insertion, the shaft that translates vertical plug movement into rotational motion, and the blocking plate that physically controls lever movement. This segmentation allows each component to perform its specific function efficiently while maintaining overall system simplicity.
3Reliability
If the shaft rotation mechanism is used to control blocking plate movement, then the interlock function is achieved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The shaft rotation mechanism is designed to be self-actuating through the plug connector assembly. When the plug is inserted or removed, it directly drives the shaft to rotate through the connection between the plug's vertical movement and the shaft's rotational movement, eliminating the need for external actuators, motors, or complex control systems.
Solution Approach 2:
The mechanism converts the vertical linear dimension of plug insertion/removal into the rotational dimension of shaft movement, which then controls the horizontal positioning of the blocking plate. This dimensional transformation allows a simple plug connection action to control the interlock state without requiring complex mechanisms in any single dimension.
Data Source
AI summary
The present disclosure provides a plug interlock device for a circuit breaker, comprising: a lever-type withdrawable interlock assembly provided at a transfer car so that inputting and withdrawal of a breaker main body can be locked; a plug connector assembly, which rises/lowers in response to insertion or separation of a control line plug into or from a connector provided at the upper part of the breaker main body; a shaft, which rotates in different directions according to the elevation of the plug connector assembly by connecting one side thereof to the lower end of the plug connector assembly; and a blocking plate connected to the other side of the shaft so as to lock or unlock the operation of the lever-type withdrawable interlock assembly while horizontally moving according to the rotation of the shaft.