Residual Current Circuit Breaker Self-Test Logic

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Solution Overview

Problem

Residual current circuit breakers with mains voltage-dependent tripping electronics often malfunction, leading to inadequate protection due to defective components, which can result in unnecessary activation and reduced operational readiness and safety.

Innovation Solution

The solution involves a residual current circuit breaker design where mains voltage-dependent functions are only activated when the mains voltage-dependent electronic tripping system is functioning correctly, ensuring that mains voltage-independent basic functions are retained even if the mains voltage-dependent tripping electronics are defective, and incorporating control means to dampen the effect of mains voltage-independent tripping electronics when the mains voltage-dependent system is operational.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mains voltage-dependent tripping electronics are added to residual current circuit breakers, then the functionality and protection capability are improved, but the reliability deteriorates due to defective components causing unnecessary activation

Engineering Contradiction:
Improveprotection capabilityVSAvoidoperational readiness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements a self-test function that activates during the first switching operation after power-on or reset. This preliminary action detects whether mains voltage-dependent tripping electronics are functioning before normal operation begins, preventing defective components from causing unreliable behavior during actual protection scenarios.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs feedback mechanisms where the self-test result influences the operational state of tripping electronics. If the self-test detects defects, the system provides feedback to deactivate or isolate the faulty mains voltage-dependent tripping electronics, ensuring only functional components are used during normal operation.

Inventive Principle:
Principle #23Feedback

2Adaptability or versatility

If both mains voltage-independent and mains voltage-dependent tripping electronics are present, then the protection coverage is enhanced, but the device complexity increases

Engineering Contradiction:
Improveprotection coverageVSAvoidelectronic system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and isolates the self-test function as a separate operational phase distinct from normal tripping operations. By separating the self-test functionality from the main tripping electronics, the system manages complexity through functional decomposition while maintaining comprehensive protection capabilities.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements dynamic control where the availability of mains voltage-dependent tripping electronics is determined at runtime through self-testing. The system adaptively switches between available tripping mechanisms based on their operational status, optimizing the balance between protection coverage and system complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2347490B1Residual current circuit breaker
Publication Date: 2018.09.05 EATON INTELLIGENT POWER LTD
  • EP2347490B1 patent drawingFigure 1~2
  • EP2347490B1 patent drawingFigure 3~4
  • EP2347490B1 patent drawingFigure 5~6

AI summary

In a residual current circuit breaker (1) having a first unit (2) which is designed to detect a residual current inside an electrical power supply system and to output an analogue residual current signal, an analogue/digital converter (3) for converting the analogue residual current signal into a digital residual current signal, a first digital signal processing unit (4), and a second unit (5) for disconnecting isolating contacts (6) in the electrical power supply system in a predefinable manner, it is proposed, for good resolution of a residual current signal over a wide dynamic range, that the residual current circuit breaker (1) has first means (7) for adapting the analogue residual current signal to the analogue/digital converter (3), in particular for adapting the analogue residual current signal in a predefinable and variable manner.