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Current unbalance is frequently encountered power quality problem. Negative sequence current leads to increase in machine temperature and unnecessary tripping of circuit breakers. Unequal phase current and harmonic current causes increased line losses and skin effect. In this paper, a new stationary reference frame control is proposed and implemented based on Positive and Negative Sequence Component Extraction. Positive sequence current is taken as reference for VSI, used as current unbalance compensator. VSI is designed to eliminate negative sequence current component thereby balance of currents are obtained. Consequently, reduction in lines losses and improvement of power factor is also observed in the power system. Keywords-unbalanced and non-linear load; current unbalance and harmonics; positive sequence; balanced current.

Voltage Unbalance is a common type of power quality problem. Sequence components occur during unbalance in three phase system. For this reason unbalance is assessed with respect to the sequence components present in the system. Voltage unbalance may adversely affect power system components connected to the system. In this paper, for symmetric and asymmetric faults, positive sequence voltage is taken as reference to generate PWM pulses and is given to the VSI to mitigate the unbalance present in the power system.