7 8 2017 ЕЛЕКТРОТЕХНИКА И ЕЛЕКТРОНИКА ELECTROTECHNICA & ELECTRONICA nd Union of Electronics, S I E L A 2016 Technical 32 International Conference Electrical Engineering and University Telecommunications of Sofia XXth International Symposium on on Information Technologies CEEC Electrical Apparatus and Technologies 20-21 September 2018 3 – 6 June 2017, Bourgas, Bulgaria St. St. Constantine and Elena resort BULGARIA Union of Electronics, Electrical Engineering and Telecommunications (CEEC) IEEE Bulgaria Section with the support of Technical Universities of Sofia, Varna and Gabrovo "Nikola Vaptsarov" Naval Academy, Varna Federation of Scientific and Technical Unions House of Science and Technology - Plovdiv Faculty of Technical Sciences, “Prof. Assen Zlatarov” University – Bourgas University of Ruse "Angel Kanchev" Regional Organization of STU - Bourgas Centre of Informatics and Technical Sciences at BFU VDE - Germany INFORMATION: Prof. R. Romansky, D. Sc. SIELA 2018 Union of Electronics, Electrical Engineering and Telecommunications (CEEC) Technical University - Sofia | 8, Kliment Ohridski Blvd. | 1000 Sofia, BULGARIA | 108, Rakovski Str. | 1000 Sofia, BULGARIA Phone: (+359 2) 965-32-95 / 965-25-30 | Fax (office): (+359 2) 962-45-77 | e-mail: rrom@tu-sofia.bg Phone: (+359 2) 987 9767 | E-mail:
[email protected] http://infotech-bg.com http://siela.tu-sofia.bg Technical University – Sofia 8, Kliment Ohridski Blvd., 1000 Sofia, BULGARIA E-mail: rrom@tu-sofia.bg WEB Site: infotech-bg.com Tel.: (+359 2) 965-32-95 / 965-25-30 Fax (office): (+359 2) 962-45-77 ELECTROTECHNICA & ELECTRONICA E+E Vol. 52. No 7-8/2017 Monthly scientific and technical journal Published by: The Union of Electronics, Electrical Engineering and Telecommunications /CEEC/, BULGARIA Editor-in-chief: C O N T E N T S Prof.