1. Faculty of Transport, Electrical Engineering and Computer Science, University of Radom, 26-600 Radom, Poland
2. Department of Electrical Systems, Lviv National Environmental University, 80381 Dubliany, Ukraine
3. Institute of Power Engineering and Control Systems, Lviv Polytechnic National University, 29003 Lviv, Ukraine
4. Faculty of Electrical Engineering, Czestochowa University of Technology, 42-201 Czestochowa, Poland