International Journal of
Physical Sciences

  • Abbreviation: Int. J. Phys. Sci.
  • Language: English
  • ISSN: 1992-1950
  • DOI: 10.5897/IJPS
  • Start Year: 2006
  • Published Articles: 2557


Detection of internal fault in differential transformer protection based on fuzzy method

Iman Sepehri Rad1, Mostafa Alinezhad2, Seyed Esmaeel Naghibi2 and Mehrdad Ahmadi Kamarposhti3*      
1Golestan Electric Power Distribution. CO, Gorgan, Iran. 2Department of Electrical Engineering, Islamic Azad University, Behshahr Branch, Behshahr, Iran. 3Department of Electrical Engineering, Islamic Azad University, Jouybar Branch, Jouybar, Iran.  
Email: [email protected]

  •  Accepted: 27 May 2011
  •  Published: 30 October 2011


Power transformers are vital and expensive components of electric power systems and it is necessary to protect them from internal faults. Differential protection is based on differential current. Occurrence of some phenomena such as inrush current, over excitation, saturation of current transformers and mismatch of current transformers cause the differential relay to operate incorrectly. In this paper, fuzzy logic is used as a powerful mathematic tool. In this method of protection, algorithm is based on ruled out non-internal fault phenomena. The results of simulations show that fuzzy protection system is able to detect occurrence of fault in less than half a cycle and this method improves protection system, satisfactorily.       


Key words: Differential protection, power transformer, fuzzy logic.