Abstract:
The switching transient is not a new phenomenon; it has been around for many decades. However, it has received more attention recently because of the greater number of failure of many electrical equipments like transformer, circuit breaker etc. because of the phenomena. Both energization and de-energization of transformer and shunt capacitor bank produce considerable amount of transient overvoltage which in turn can cause insulation failure of transformer and malfunctioning of protective equipments. The worst case occurs if the frequency of the transients matches the resonance frequency of the transformer causing voltage and current magnification to a level that exceeds the BIL of transformer. The purpose of this thesis work is to study the switching transient over-voltages that occur during different switching events in an arbitrary distribution network. We have analysed the network for switching actions like switching of transformer, capacitor bank and switching of load. The analysis is done considering both overhead lines and underground cables to make a comparative study. Transient short circuit fault also causes high frequency overvoltage; which is analysed in this work. Finally, the analyses of the output data is done to find out the main reasons for this transient and some recommendations are given to minimize the effects of transient overvoltage.
Description:
We are thankful to Almighty Allah for giving us strength, integrity and patience for the successful completion of our thesis work. We are greatly indebted and respectful to our supervisor Dr. Abdul Hasib Chowdhury for his great support, guidance and encouragement, not only to our research work but also his diligence and generosity. His valuable suggestion greatly helped us in understanding the intricate problem involved in completion of the work. He has guided us with his remarkable expertise in this sector during the entire progress of the work.
We would like to thank Dr. Abdul Hasib Chowdhury, Professor, Department of Electrical and Electronic Engineering, BUET, a brilliant teacher and human being who lighted our way through the course of our undergraduate work. His enthusiasm, broad knowledge and sharp thinking gained our most sincere admiration. His caring and understanding touched us deeply. Through his teaching, discussion and contribution, we gained significant insight into the field of different types of transient analysis in the distribution sides of power system.
We also extent our thanks and gratitude to the teachers and students of EECE department, MIST who helped us time to time in the laboratory and also in the department to carry out our research work smoothly.
