International Journal of
Physical Sciences

  • Abbreviation: Int. J. Phys. Sci.
  • Language: English
  • ISSN: 1992-1950
  • DOI: 10.5897/IJPS
  • Start Year: 2006
  • Published Articles: 2572

Full Length Research Paper

Impact of distributed generations on power system protection performance

Hadi Zayandehroodi1*, Azah Mohamed2, Hussain Shareef2 and Marjan Mohammadjafari1
1Department of Electrical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran. 2Department of Electrical, Electronic and Systems Engineering, Universiti Kebangsaan Malaysia (UKM), Selangor, Malaysia.
Email: [email protected]

  •  Accepted: 20 June 2011
  •  Published: 18 August 2011


Though distributed generators (DGs) have significant economic and environmental benefits, increased penetration of DGs will impose significant technical barriers for the efficient and effective operation of bulk power systems. Increased fault current contribution and load flow changes are the major two impacts on utility systems, and these will affect existing protective relaying, especially overcurrent relays. To ensure safe and selective protection relay coordination, the impact of DGs should be taken into account when planning DG interconnection. This paper presents an introduction of DGs and an overview of the impacts of DGs on system protection relay coordination. Several protection issues are identified to study the requirements for protection in the presence of DGs are also discussed.


Key words: Distributed generator (DG), protection coordination, distribution network, overcurrent relay.


DGs, Distributed generators; ac, alternating current; dc/DC, direct current;CB, circuit breaker; LV, low voltage.