Arduino-Based Real-Time Monitoring and Automatic Protection of AC Loads Against Voltage and Current Abnormalities

The developed Arduino-Based Under-Voltage, Over-Voltage, Under-Current and Over-Current Protection System for AC Loads provides an effective and economical approach for monitoring and protecting electrical loads. The system integrates an Arduino ATmega328P/Arduino Uno, ZMPT101B voltage sensor, ACS712-type current sensor, 16×2 LCD, and relay module to continuously monitor voltage and current conditions. For the 60 W demonstration bulb, the calculated current at 230 V is approximately 0.261 A. The selected voltage range of 210–240 V and prototype current range of 0.20–0.35 A allow the controller to distinguish normal and abnormal operating conditions. During normal operation, the relay keeps the load connected, whereas under-voltage, over-voltage, under-current, or over-current conditions cause automatic relay disconnection. The LCD provides real-time electrical measurements and fault information, improving system monitoring and user awareness. The results demonstrate that a single programmable microcontroller can integrate sensing, decision-making, indication, and automatic switching in a compact protection system. The proposed prototype is therefore suitable for educational, laboratory, domestic, and small-load applications and provides a foundation for developing more advanced intelligent electrical protection systems.

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