A Physical Model for the Study of Losses in Networks Up to 1000V, Taking Into Account Harmonics with Different Modes of Operation of Neutral Power Transformers

The article deals with the issues of additional losses in transmission distribution lines up to 1000 volts from the effect of such an indicator of the quality of electricity as non-sinusoidal voltage, which includes harmonics of the spectrum of the supply network. Physical and computer simulations were used for the study. The model includes a simulation of a line in the form of active and reactive resistances, a motor load in the form of an asynchronous electric motor loaded with an asynchronous generator, a separation transformer used to create various neutral grounding systems and a distortion generating device designed to simulate harmonic distortions of the supply voltage. For physical modeling, a test bench has been developed that allows conducting studies of power losses in the line and heating of asynchronous electric motors, taking into account the grounding mode of the neutral of the power transformer. For computer modeling, the MATLAB/Simulink dynamic modeling environment was used, in which the replacement circuit of the test bench was assembled. The results of experiments on the study of power losses for heating an asynchronous electric motor due to the presence of harmonics in the supply voltage are presented.