Under the `Smart Grid' initiative, future medium and low voltage distribution grids would incorporate renewable sources like rooftop solar, etc. This would require bi-directional power flow between the generation and the loads. For optimal fault isolation and distribution automation, directional protection would be of great advantage. However, traditional directional overcurrent relays utilize the reference voltage phasor for estimating the direction of the fault, requiring measurement of both current and voltage using respective sensors. This makes the directional overcurrent relays prohibitively costly than the non-directional type for distribution side utilizations. Novel current-only directional protection algorithms have been proposed and demonstrated. However, as the current-only approach relies on the prefault current direction as the polarizing quantity, if the direction of the prefault current changes during normal condition, the direction definitions (forward or reverse) would be vice versa. This is a problem for the current-only approach. In this paper, a signal processing-based solution is proposed, leveraging the fact that change in direction in prefault condition is associated with a phase angle change of 180°.