Fuzzy logic based fault detection and classification in Unified Power Quality Conditioner (UPQC)-compensated distribution line

Presently, power quality and power system protection are the two biggest challenges faced by power systems. In this paper, both problems have been addressed by means of designing a fuzzy logic based fault detector and classifier for an UPQC-compensated distribution line. An UPQC has been modeled for a given three-phase distribution line which is used to mitigate almost all problems related to power quality pertaining to voltage and current distortions. Then, a fuzzy logic based classifier is used in conjunction with the line to detect and classify all types of shunt faults (Line-Ground, Line-Line-Ground, Line-Line-Line faults). This classifier uses the normalized values of line currents and exploits the rise of current in faulty phases to determine types of faults. The proposed scheme was tested by simulating the faults at various locations of the line, and the classifier was found to correctly detect and classify all faults irrespective of fault locations. The simulations have been performed using MATLAB-Simulink software environment.