Overvoltages Transmitted in the Transformer Windings on the Lightning Impulse—An Analytical Method for Determination and Experimental Measurements

Overvoltages are brief and significant increases in the voltage level in an electrical system. They can be caused by a variety of factors, but the most common are associated with atmospheric discharges (lightning). When lightning strikes a power line, the resulting shock wave can induce surges in el...

Full description

Saved in:
Bibliographic Details
Main Authors: Maria-Cristina Nițu, Livia-Andreea Dina, Ileana-Diana Nicolae, Marian-Ştefan Nicolae, Paul-Mihai Mircea
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/15/11/5861
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Overvoltages are brief and significant increases in the voltage level in an electrical system. They can be caused by a variety of factors, but the most common are associated with atmospheric discharges (lightning). When lightning strikes a power line, the resulting shock wave can induce surges in electrical equipment that is connected to that line, including transformers. The authors develop an analytical method in order to determine the maximum values of the overvoltages propagating in the transformer windings in case of lightning impulse. It is considered that the transmitted overvoltages consist of an inductive component (magnetic dispersion is neglected, as well as the energy exchange between the capacitances and inductances of the energized winding) and a capacitive component (between the energized winding and the receiving winding; in this case, the emphasis is on the energy exchange between the series capacitance and the inductance of the series winding). The proposed method was applied on a TTUS—ONAN/ONAF 31.5/40 MVA, 110/5/6.6 kV power transformer, and the obtained results were validated by experimental tests. The percentage error between the results obtained by modeling and the results obtained from transformer testing was less than 2%.
ISSN:2076-3417