Аннотация:
In this study, power quality coefficients that determine the distortion of electrical systems
are established. The power factor is chosen as a universal criterion for electromagnetic and electro-
energetic compatibility of distorted sources and distorting loads. Mathematical expressions are
obtained for its calculation in various cases of electrical systems distortion. As an application
example, power balances and power factors of a variable frequency asynchronous drive system are
considered. The criterion: the power factor not only determines the energy and electromagnetic
compatibility of the drive with power supply, but it also evaluates drive efficiency. Experimental
studies were carried out under usage of inexpensive, commonly used measuring devices both on the
grid side of the frequency converter and on the asynchronous motor side. The studied coefficients
were determined in two ways: measuring instruments and analysis of oscillograms. The second
method for determining the above coefficients from oscillograms of currents and voltages also
requires finding the total harmonic distortion (THD) of currents and voltages for the corresponding
load adjusting points. The similarity of the obtained results shows that both of these methods can be
applied. According to the operating mode of the load, the criterion is calculated as an average range
in a certain range of speed control, or it is determined by considering a given tachogram of speed
changes. The results of experimental studies confirm the correctness of the theoretical provisions
