Comparative Performance Analysis of PI and Fuzzy Logic Controlled UPFC Under Single Line-to-Ground Fault Conditions

Abstract

Electric power systems form the backbone of industrial and economic development. With the continuous growth in global electricity demand, the large-scale generation and transmission of power to residential and industrial consumers have become increasingly critical. Ensuring flexible, efficient, and reliable operation of modern power networks remains a significant challenge, particularly under heavily loaded and faulted conditions. Flexible AC Transmission System (FACTS) devices offer an effective solution by enhancing power flow control, improving system stability, and increasing transmission capacity utilization.

This work presents a comparative performance analysis of the Unified Power Flow Controller (UPFC) under a single line-to-ground (S-L-G) fault condition. The study demonstrates that the Fuzzy Logic Controller (FLC) outperforms the conventional Proportional–Integral (PI) controller in terms of transient stability enhancement, oscillation damping, and faster system recovery. A detailed multi-machine power system model subjected to various fault scenarios is developed and simulated using MATLAB to validate the effectiveness of the proposed control strategies.