Objective: The objective of this project is to design and implement a comprehensive protection system for electrical power networks, focusing on safeguarding against overvoltage, undervoltage, and overload conditions. The primary aim is to ensure the reliable and stable operation of the system by detecting potential faults and initiating appropriate protective responses. A key feature of the project is the seamless graphical synchronization between the user interface and the hardware module, enabling real-time monitoring and control. The system accurately displays live voltage readings, load status (on/off), and the current flow through the network. Moreover, it includes an automated protection mechanism: if the load exceeds the predefined threshold, the system instantly shuts down and issues a warning on the display to prevent equipment damage.

Tool used: Arduino IDE (for implementing code corresponding the system specification), EasyEDA (Schematic drawing).

Programming Language used: C++

Figure: Overall outlook of the protection system project, illustrating the hardware setup, graphical interface, and real-time monitoring features.

Abstract: A voltage-monitoring sensor continuously measures input voltage levels and detects abnormal fluctuations. When an under-voltage or over-voltage condition is identified, the system triggers a protective relay that disconnects power to the affected circuit. After a predefined time delay, the relay automatically resets and restores power once normal conditions are re-established. The under and over-voltage protection circuitry is implemented using comparators to ensure accurate threshold detection.

The protection system also includes a current-sensing module that monitors real-time load current. If the current exceeds the predefined reference limit, the protective relays operate sequentially to disconnect all loads in a controlled manner. This staged tripping mechanism prevents excessive stress on the system and mitigates the risk of a complete blackout, thereby enhancing overall system reliability and safety.

Figure: Block diagram of protection system project.

Component List:

• Node MCU Mega WI-FI R3 Atmega  2560.

• 3.5 inch LCD Display.

• ACS712 Current Sensor.

• ZMPT101B Voltage Senso.

• 4 Channel Relay Module.

• Phase indicator bulb.

• Filament Bulb(40W).

Learnings:

• Gained hands-on experience in microcontroller interfacing, including sensor integration and peripheral control.

• Developed a strong understanding of User Interface (UI) design, enabling seamless synchronization between hardware components and the graphical interface.

• Learned the operational principles of voltage and current sensors, along with their respective libraries and configuration in the Arduino environment.

• Acquired skills in system design, applying real-world problem-solving methodologies to develop reliable and scalable solutions.

• Strengthened proficiency in C++ programming within the Arduino IDE for embedded system implementation.

Difficulties Faced: During the interfacing of the ZMPT101B voltage sensor, we encountered significant instability in the measured voltage values. Within every 10–15 samples, the sensor occasionally produced unrealistic or highly fluctuating readings. As a result, the system behaved unpredictably because the raw voltage values were being used directly for comparison in the protection algorithm. This undermined the accuracy and reliability of the overall system and initially prevented it from functioning as intended.

To address this issue, we implemented a sampling and averaging technique. By collecting 100 consecutive voltage samples and computing their average before performing any comparisons, we were able to substantially reduce measurement noise and improve the stability of the readings. Although this filtering method introduced a slight increase in system response time, it significantly enhanced the accuracy and effectiveness of the protection mechanism.

My role in this project:

• Designed the entire user interface (UI) and ensured seamless synchronization between the hardware system and the graphical interface.

• Developed and implemented the complete software code, including sensor integration, protection logic, and system control features.

• Led the system design, covering both functional architecture.

• Proposed and implemented the hardware setup, including the sampling-average technique to stabilize voltage readings and enhance system reliability.