Abstract: Numerical relays play a vital role in modern power system protection by providing fast, reliable, and accurate fault detection. Unlike conventional electromechanical and static relays, numerical relays use microprocessors and digital signal processing techniques to analyze electrical parameters and generate trip signals during abnormal conditions. This paper presents a comparative analysis of different algorithms used in numerical relays, implemented using Python. The study focuses on commonly used protection algorithms such as overcurrent, distance, and differential protection techniques. Each algorithm is modeled and tested under various fault conditions including line-to-ground, line-to-line, and three-phase faults.

Key performance parameters such as response time, detection accuracy, sensitivity, and reliability are evaluated. Simulation results demonstrate that digital implementation of relay algorithms improves fault detection speed and accuracy while reducing computational complexity. Among the analyzed techniques, differential protection shows superior performance in terms of fast response and precision, while distance protection provides effective zonebased fault identification. The use of Python enables flexible modeling, easy simulation, and efficient comparison of relay characteristics. The findings of this study contribute to better understanding and practical implementation of numerical relay algorithms in modern smart grid and power system protection applications.

Keywords: Numerical Relay, Overcurrent Protection, Distance Protection, Differential Protection, Python, Power System Protection.

Downloads: | DOI: 10.17148/IJIREEICE.2026.14306