FIELD: measurement technology.
SUBSTANCE: invention relates to electric measurements and can be used for quality control of electric power in power grids. Method includes identification of abnormal components of current loads i1a, i2a, determining own fractional shares in variation of quality of resultant current for branches to sources of current load, determination of mutual share participation in change of electric energy quality of interaction of pairs of branches with sources of current loads, then resulting change of electric energy quality determination in unit in accordance with formula. At that, own share participation in change of quality of resultant current unit from branches with sources of current load is determined by averaging of squares for period of abnormal components of these currents. Determination of mutual share participation in change of quality of resultant current of interaction of pairs of branches with sources of current load, by averaging of product of abnormal components of current loads for same period. Determination of resulting changes in resultant current quality, in accordance with following formula 
where i1a, i2a are abnormal components in branches current loads, SU (i1a), SU (i2a) are respectively own share participation branches with sources of current loads, VU (i1a,i2a) are mutual share participation of two branches of loads.
EFFECT: more accurate determination of additional active power losses in network, id est more accurate determination of power system efficiency.
4 cl, 3 dwg
