This book is devoted to one of the main problems of modern electrical power engineeringpower transformer diagnostics. The first three chapters discuss the fundamentals: The first chapter presents the physical reasons for power transformers failures and the technical and economic consequences of disruption of the normal operation. The second chapter reviews the standard technologies for monitoring the state of the high-voltage transformers. The third chapter tells about monitoring the condition of transformer windings based on the pulse method.

The fourth chapter presents the technologies for transformer windings condition controlled by means of nanosecond pulses. The stages of improving the pulsed method based on a short probing pulse of the nanosecond range, the results of experiments on identifying the radial and axial displacements of the winding, studies of the effect of the duration and shape of the probing pulse on the sensitivity of the diagnostic procedure, and the stages of developing a mathematical as well as physical model of a power transformer are consistently presented.

Alexey V. Lavrinovich was born on 10 October 1986. He received the M.S. degree in Electrical Engineering from Tomsk Polytechnic University in 2008. From 2008 up to 2017, he worked as researcher and engineer in High Current Electronics Institute, Tomsk, doing research with high voltage pulsed power. Since 2017 he has been working in Tomsk research and design institute of oil and gas, Tomsk, Russia. His research interests focus on power transformer diagnostics and providing of high voltage equipment stable work.   

Valeriy A. Lavrinovich was born on 7 November 1948. He received the Ph.D. degree in 1985 from High Current Electronics Institute of the Russian Academy of Sciences (Tomsk, Russia) and the Doctor of Science degree in 2005 from Tomsk Polytechnic University (Tomsk, Russia). Both dissertations are dedicated to investigation and elaboration of high-voltage vacuum spark gaps and commutators. From 1989 to 1998 he was the director of Russian Research Institute of Electrotechnical Industry. Now he is a professor at the Department of Electrical Power Engineering Systems and High Voltage Engineering of Tomsk Polytechnic University. He is the laureate of Russian Government Prize in the area of Science and Technology. Professor Lavrinovich published more than 90 scientific articles. His research interests focus on pulsed power and electrical power engineering systems.

Alexey V. Mytnikov was born on 2 June 1966. He received the M.S. degree in Electrical Engineering from Tomsk Polytechnic University in 1988. He received the Ph.D. degree in 2001. He is an Associate Professor of Power Engineering Institute, Tomsk Polytechnic University (Tomsk, Russia). His research interests focus on power transformer diagnostics, high voltage technologies and engineering pedagogics. Also, he provides full range of special courses for bachelor and master teaching specialization High Voltage Power Engineering, including lectures, practices and workshops.New technology of winding condition control, which is based on the nanosecond probing impulses, is the result of his experimental work. New diagnostic complex has been designed and engineered. Simulations are a useful tool but as Hippocratos once said: Clever man is not who knows a lot, but whose knowledge is useful. I follow this motto now.  Associate Professor Alexey V. Mytnikov published more than 70 scientific articles.

Vasiliy Ya.  Ushakov was born in Kazakstan, 1939. He received Ph.D. degree in 1965 and Doctor of Science degree in 1973 from Tomsk Polytechnic University, Tomsk, Russia. Currently, he is a Professor of School of Power and Power Engineering at the Tomsk Polytechnic University. In different years, he held the following positions: the Head of High Voltage Department of the Tomsk Polytechnic University (TPU), the Head of High Voltage Research Institute at TPU, the Vice-rector for Research of TPU, the Head of Regional Resources Saving Centre. He has many years of experience teaching special disciplines (High-voltage engineering, Electrical engineering. Current state, problems and perspectives, Energy saving in the enterprises of fuel and energy complex) in Russian and in English (including abroad South Korea, spring 2005) and the course "Professional English" for Russian-speaking students. He has published over 300 scientific articles and 24 monographs and textbooks (four of them in Springer Verlag), received 38 invention certificates and patents. Under his leadership, 34 candidate and 6 doctoral dissertations were defended. He is currently a member of the Editorial Board of the journal Russian Physics and participant of Dissertation Council in the Tomsk branch of Russian Academy of Sciences.

Failure reasons of power transformers.- Traditional technologies for condition monitoring of high-voltage transformer.- Diagnostics of the condition of transformer windings by probing pulses of microsecond duration.- Diagnostics of the transformer winding condition by probing pulses of nanosecond duration.