Dissertation on the Field of Power Systems and High Voltage Engineering
18.03. / 12:00 - 15:00
Title: Lightning-Induced Overvoltages in Medium Voltage Distribution
Systems and Customer Experienced Voltage Spikes.
Abstract:
In Finland, distribution transformers are frequently subjected to lightning strokes for which they are continuously protected by spark-gaps. The aim of this work is to model the fault type probability (1-ph, 2-ph or 3-ph fault type) in distribution networks due to MV spark-gap operation and to evaluate the proposed model using statistical data. Also, an accurate high frequency model of the distribution transformer under lightning strokes is introduced and verified using experimental measurements. The proposed model of the distribution transformer covers the behavior of sparkgap breakdowns under applying impulse signals. Finally, a study is carried out to mitigate the overvoltages by allocating the surge arrester at secondary side of the distribution transformer with concerning MV spark-gap operation.
Doctoral candidate: MSc Nehmdoh A. Sabiha
Opponent: Professor Maria Teresa Correia de Barros, Technical University of Lisbon, Portugal
Superviser: Professor Matti Lehtonen, Aalto University School of Science and Technology
Name of the dissertation
Field of research: Power Systems and High Voltage Engineering
www-address: http://lib.tkk.fi/Diss/2010/isbn9789526030463/
More information:
Nehmdoh A. Sabiha
Tel. +358-9-470 25384, nehmdoh.sabiha@tkk.fi
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