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Mathematical Problems in Engineering
Volume 2012, Article ID 717195, 12 pages
Research Article

Fuzzy Timing Petri Net for Fault Diagnosis in Power System

1Faculty of Electrical Engineering, Islamic Azad University, Najafabad Branch, No 252 Khaghani Street, 8175848591 Isfahan, Iran
2Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81300 Johor Bahru, Johor, Malaysia

Received 8 March 2012; Accepted 27 June 2012

Academic Editor: Zheng-Guang Wu

Copyright © 2012 Alireza Tavakholi Ghainani et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A model-based system for fault diagnosis in power system is presented in this paper. It is based on fuzzy timing Petri net (FTPN). The ordinary Petri net (PN) tool is used to model the protective components, relays, and circuit breakers. In addition, fuzzy timing is associated with places (token)/transition to handle the uncertain information of relays and circuits breakers. The received delay time information of relays and breakers is mapped to fuzzy timestamps, π(τ), as initial marking of the backward FTPN. The diagnosis process starts by marking the backward sub-FTPNs. The final marking is found by going through the firing sequence, σ, of each sub-FTPN and updating fuzzy timestamp in each state of σ. The final marking indicates the estimated fault section. This information is then in turn used in forward FTPN to evaluate the fault hypothesis. The FTPN will increase the speed of the inference engine because of the ability of Petri net to describe parallel processing, and the use of time-tag data will cause the inference procedure to be more accurate.