In this article are presented the issues of one of the main power quality indicators of voltage unbalance and ways to solve them. An algorithm for measuring the level of the asymmetry coefficient of the reverse and zero sequence and the influence of the load unbalance on the amount of power and electricity losses are presented, as well as modeling the determination of the values of powers, voltages and currents and, accordingly, their symmetrical components. The use of domestic devices for monitoring the power quality in a separate power system is proposed. The results of measurements of electrical networks are presented.