Low-Voltage Circuit Breaker Functional Testing for Safe Interruption
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Solution Overview
Problem
Existing circuit breaker devices for low-voltage circuits lack adequate safety features to ensure reliable operation and protection, particularly in preventing accidental switching on or off due to faulty electronic interruption units.
Innovation Solution
A circuit breaker device with a mechanical isolating contact unit and an electronic interruption unit using semiconductor-based switching elements, incorporating a measurement impedance for functional testing and fault detection, ensuring safe operation by preventing current flow when fault conditions are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If an electronic interruption unit is used to replace mechanical trip units, then the circuit breaker achieves faster and more precise current interruption, but the reliability is reduced due to potential faults in semiconductor switching elements
Solution Approach 1:
The patent implements a preliminary functional test of the electronic interruption unit before the circuit breaker can be operated. The control unit activates the semiconductor switching elements and verifies their switch-on and switch-off capabilities through measurement impedance. Only after successful verification is an operating permit granted, ensuring the electronic interruption unit is fault-free before actual use, thus resolving the reliability concern while maintaining the speed advantage.
2Reliability
If functional testing of the electronic interruption unit is implemented, then operational safety is improved, but the device complexity increases due to additional measurement impedance and control unit functions
Solution Approach 1:
The control unit is designed to perform multiple functions: it controls the semiconductor switching elements during normal operation, executes functional tests by activating switching elements and measuring current through measurement impedance, evaluates test results, and grants or denies operating permits. This multi-functionality allows the control unit to handle both operational control and safety verification without requiring separate dedicated testing hardware, thus improving operational safety while limiting the increase in device complexity.
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 enhances operational safety by accurately checking the switch-on and switch-off capabilities of the electronic interruption unit, preventing accidental switching and ensuring only a functional circuit breaker device can be operated, thus increasing safety in low-voltage circuits.
Implementation Method 1
A high-resistance measurement impedance is connected between two conductors of the low-voltage circuit in such a way that, when contacts of the mechanical isolating contact unit are open and the electronic interruption unit is switched on, a measurement current flows through the electronic interruption unit via grid-side connections of the circuit breaker device
Data Source
AI summary
A circuit breaker device for protecting an electrical low-voltage circuit includes a housing having grid-side connections and at least one load-side connection. A mechanical isolating contact unit is connected to an electronic interruption unit in series, the mechanical isolating contact unit being associated with the load-side connection and the electronic interruption unit being associated with the grid-side connection. The level of the current in the low-voltage circuit, in particular between the grid-side phase conductor connection and the load-side phase conductor connection, is ascertained. If current limits and/or current/time limits are exceeded, a process for preventing a current flow of the low-voltage circuit is initiated. A measurement impedance is provided between two conductors of the low-voltage circuit. Said measurement impedance is connected to the connection between the mechanical isolating contact unit and the electronic interruption unit.