Abstract:

In this article the experience by the on-line teaching on unbalanced three-phase systems, which was applied during the Covid-19 pandemic is presented.
Modern electric power systems for production, transmission and distribution of electricity are three-phase. For their proper functioning it is necessary to know well the processes in them, the devices and possible damages that would occur and disrupt their work.

That is why it is important for future electrical engineers to get well acquainted with three-phase systems, to study the methods for measuring the active and reactive power in them. They must be able to calculate electrical values in the event of a system failure. The purpose of teaching three-phase systems is that theoretical knowledge to be successfully applied by students in practical classes. In the teaching of three-phase systems, one of the main tasks is to establish the influence of the asymmetry, introduced in one of the phases of consumers, on the currents, voltages and powers in the individual phases.

Solving problems of three-phase systems requires knowledge in both electrical engineering and mathematics. Knowing well and applying the basic laws of theoretical electrical engineering, the student receives expressions with real or complex numbers. An opportunity to simplify mathematical calculations is the use of the software product MatLab. In this paper a program is presented that calculates certain electrical values when entering the parameters of the circuit correctly.

The developed methodology also includes simulation of some of the research in addition to the theoretical acquaintance with the material. The use of simulations in practical training in all technical disciplines is the basis for modernizing the educational system of each country and an essential element of European educational policy. Incorporating research into a virtual environment is particularly useful in pandemic training. The methods proposed in this article were tested in the online training during the quarantine because of Covid-19 pandemic. The methods proposed in this article were used in the online training during the quarantine because of Covid-19 in the disciplines "Electrical Engineering", "Measurements in Electrical Engineering and Electronics", studied by students majoring in "Electrical Engineering" at the Faculty of Physics and Technology at the University of Plovdiv Paisii Hilendarski. Observations are that the use of simulations of various electrical processes is used to better understanding the nature of phenomena in three-phase electrical circuits or devices. This helps the students to work more confidently with the measuring equipment.

Keywords:

Education, Computer Simulation, Electrical Engineering, Three-phase electrical circuit.