Committee Chair

Eltom, Ahmed H.

Committee Member

Kobet, Gary L.; Karrar, Abdelrahman A.


Dept. of Electrical Engineering


College of Engineering and Computer Science


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


Geomagnetic Induced Current (GIC) is a quasi-DC current that may have adverse effects on power system reliability. Several GIC blocking device (NBDs) designs are available, but the majority is capacitive. Concerns have arisen about the effects of NBDs on distance-protection relays. To investigate their impact, real-time simulation (of IEEE-39 bus system) with actual hardware-in-the-loop testing is utilized. The study showed that these relays are not affected by the insertion of NBDs regardless of the polarizing quantity used. However, during close-by fault, the energy through NBDs’ MOV is excessive. Also, the potential for resonance between NBDs and the system was investigated. The results indicate the possibility for resonance under steady-state imbalance, however, in most cases resonance is masked by a high damping system, thus it becomes indiscernible. But under fault conditions, even for non-resonating conditions, care is needed to avoid over-voltages by providing a backup spark-gap for MOV devices.


Throughout the past two years, Dr. Eltom has been an excellent mentor and advisor. His continuous appreciation and uninterrupted encouragement were my fuel to complete my study at UTC. I would like to convey my finest gratitude for all he has done in these two years. Without the gracious help of Dr. Karrar and Mariana Kamel, this work would not be completed. Sincere thanks and gratitude should be given to them for their endless help, unbroken support and invaluable contribution. Also, thanks should be given for the previous graduate students; Abubkr, Mustafa and Musab for sharing their experience and time with me. Acknowledgement is due to University of Tennessee at Chattanooga – Electrical Engineering Department for providing the latest equipment and software to be used in this project. The availably and the easy access to real time simulators and protection relays provided a good environment to develop such work. Also, special thanks to Gary Kobet and Ian Grant (TVA) for taking out of their private time to assist in this work and advise its direction. In addition, I recognize Tennessee Valley Authority (TVA) for providing fund and support to this work, and provide us at UTC a chance to take a look at a real-world cutting edge problem. I hope the relationship between TVA and UTC continues to grow and prosper. Finally, deep appreciation should be expressed for all my friends and colleagues that provided different kinds of support during this project.


M. S.; A thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Master of Science.




Electric power system stability


GIC; Hardware in the loo HIL; Distance protective relays; IEEE 39 bus system; Neutral blocking device NBD; Hypersim

Document Type

Masters theses




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