Abstract : This study discusses the design and implementation of a overcurrent protection system using two types of relays, namely Inverse Time Overcurrent Relays and Constant Time Overcurrent Relays based on Arduino Uno microcontrollers. The system is designed to detect and respond to overcurrent disturbances that occur at resistor loads using current sensors, relay modules, and LCD displays. In an inverse time system, the disconnection time depends on the magnitude of the interference current, where the larger the current, the faster the relay works. On the other hand, in a constant time system, the relay will cut off the current at a predetermined time, regardless of the size of the current. The Arduino Uno acts as a controller brain that processes data from the current sensor and determines the disconnection logic. The test was carried out to evaluate the relay working time characteristics of the interference current variation as well as the effect of the multiplier factor value on the disconnection speed. In addition, the system is also equipped with a PZEM-004T CT module for real-time monitoring of electrical parameters and a 16 2 LCD display as a user interface. The test results show that the system is able to work effectively according to the characteristics of each type of relay. This prototype offers a practical and economical solution in the simulation of electrical protection systems, particularly in microcontroller-based learning and development environments.
Bustani et al. (2026) studied this question.