Lightning Induced Over-voltages in Power Transformer and Voltage Spikes in Connected Load

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Journal Title
Journal ISSN
Volume Title
Sähkötekniikan korkeakoulu | Master's thesis
Date
2017-10-23
Department
Major/Subject
Electrical Power and Energy Engineering
Mcode
ELEC3024
Degree programme
AEE - Master’s Programme in Automation and Electrical Engineering (TS2013)
Language
en
Pages
61+8
Series
Abstract
Power Transformers are subjected to lightning strokes, which causes the voltage at the secondary side to rise abruptly. The main aim of the report is to investigate the voltage at the medium and low voltage side in electrical system of a power plant when the high voltage power transformers are subjected to lightning strokes. Based on modelling and simulations implemented in EMTP/ATPDraw, the voltage at the 15.75 kV, 6 kV and 0.4 kV is determined to ensure if the transferred over-voltage is within the basic insulation level (BIL) of the connected equipment. Transformer frequency model, surge arrestor, cables and transmission tower are arranged in a single environment of EMTP/ATPDraw. A study is carried out to analyze the transferred transient over-voltage in the low voltage side taking the scenario of direct stroke and back flashover. Combination of different surge arrestor are implemented and analyzed to mitigate the transient voltage transferred to the medium and low voltage side.
Description
Supervisor
Lehtonen, Matti
Thesis advisor
Lehtonen, Matti
Keywords
overvoltage, flashover, transformer, surge arrestor, capacitance
Other note
Citation