Residual-current Circuit Breaker Inhibits False Tripping
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Solution Overview
Problem
Residual-current circuit breakers that trip based solely on the magnitude of residual currents can disconnect downstream sub-grids unnecessarily, causing costs and compromising technical processes due to brief, non-hazardous currents.
Innovation Solution
A residual-current circuit breaker with a first circuit arrangement that inhibits tripping when a residual current has a duration shorter than half a period of the grid frequency, ensuring that only hazardous currents lead to disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the residual-current circuit breaker trips based solely on the magnitude of residual current, then protection against dangerous body currents and fire is ensured, but unnecessary disconnections occur due to brief non-hazardous currents
Solution Approach 1:
The circuit arrangement performs preliminary evaluation of the residual current waveform characteristics before triggering tripping. By analyzing whether the current exceeds the tripping threshold for a sufficient duration (half-period of grid frequency), the system preliminarily determines if the current is hazardous, preventing premature disconnections while maintaining protection reliability
2Productivity
If time delays are incorporated into the tripping process, then brief non-hazardous currents are avoided, but residual currents amounting to a half-wave still cause unnecessary tripping
Solution Approach 1:
The invention changes the evaluation parameter from simple time-delay to waveform characteristic analysis. By assessing whether the residual current exceeds the tripping threshold for a duration corresponding to half the grid frequency period, the system accurately distinguishes between hazardous and non-hazardous currents, preventing both premature and delayed tripping
Data Source
AI summary
A residual-current circuit breaker includes switching contacts and at least one residual current detector configured to determine a residual current signal. The residual-current circuit breaker is configured to bring about an opening of the switching contacts upon the detection of a residual current greater than a pre-definable tripping current. A first circuit arrangement is configured to inhibit tripping of the residual-current circuit breaker when a residual current occurs that has a duration that is shorter than half a period of a grid frequency of an associated electrical grid.