Microcontroller-based Residual Current and Trip Time Validation System for RCCB/RCBO

Overview

This project implements a microcontroller-based validation system for testing and verifying RCCB/RCBO devices through residual current measurement and trip time analysis. The system was developed to support production testing and compliance validation by measuring leakage current conditions and evaluating breaker response time under defined thresholds.

The solution uses a current transformer (CT) and analog signal processing circuitry to sense residual current, while the microcontroller performs ADC-based threshold detection and trip time measurement. The system was used for validation of RCCB/RCBO units according to IEC 61008 and IEC 61009 testing requirements.

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Objective

The objective of this project was to design and implement a reliable validation platform for RCCB/RCBO testing in a production environment. The system was intended to support residual current measurement, threshold-based fault simulation, and trip time verification to improve testing consistency and process efficiency.

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System Architecture

The system is composed of the following functional blocks:

• Residual current generation/test condition setup
• Current transformer (CT) based current sensing
• Analog signal conditioning stage
• Microcontroller with ADC-based monitoring
• Threshold comparison and trip time measurement logic
• Output validation for IEC-compliant test conditions

Data Flow

Residual Current Test Input → CT Sensor → Analog Signal Conditioning → Microcontroller ADC → Threshold Detection → Trip Time Measurement → Test Validation

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Hardware Components

• Microcontroller-based control and measurement unit
• Current transformer (CT) for residual current sensing
• Analog signal conditioning circuitry
• ADC input stage for current threshold monitoring
• Timing and validation logic
• Test interface for RCCB/RCBO measurement

Supporting circuitry

• Resistors and capacitors for filtering and scaling
• Analog conditioning components for CT output processing
• Stable power supply section
• Interface circuitry for validation and measurement signals

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Firmware / Control Logic

The system firmware was designed to monitor conditioned analog signals from the sensing stage and evaluate RCCB/RCBO behavior under defined test currents.

Main implemented functions

• Residual current signal acquisition
• ADC-based threshold detection
• Trip time measurement for protection device response
• Validation for defined current levels, such as 30 mA and 100 mA
• Support for standardized production test workflow

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Measurement and Validation Features

• Residual current measurement using CT sensing
• Analog front-end signal processing for reliable ADC input
• Threshold-based breaker response detection
• Trip time evaluation for RCCB/RCBO devices
• Validation aligned with IEC 61008 / IEC 61009 test requirements
• Support for production process optimization and repeatable testing

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Test Levels

The project included validation support for representative residual current test thresholds such as:

• 30 mA
• 100 mA

These thresholds were used for trip detection and timing analysis during RCCB/RCBO validation.

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Standards Reference

This project was developed with validation objectives aligned to:

• IEC 61008
• IEC 61009

These standards are commonly associated with residual current operated circuit breakers and related protection device verification procedures.

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Applications

• RCCB production testing
• RCBO validation systems
• Electrical protection device verification
• Industrial quality control and test automation
• Standardized trip response testing

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Future Improvements

• Automated test data logging
• PC-based dashboard for result visualization
• Extended test coverage for additional leakage current levels
• Digital reporting for pass/fail classification
• Integration with automated production test stations

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Note

• This repository documents the system concept, measurement logic, and validation approach of the project.
• Hardware photographs, detailed schematics, firmware source files, and production test documents are not publicly available due to company restrictions.