To overcome the limitations of existing methods in effectively separating and accurately calculating load unbalance currents under asymmetric grid voltages，a novel computational method is proposed for public connection points in distribution networks. Based on the definition of an ideal load and the fundamental concept of load-current decomposition specified in German standard DIN 40110-2，the equivalent unbalanced conductance and lumped parameters of the load are first calculated. By exploiting the superior negative-sequence frequency selectivity of the fractional-order structural algorithm，the reactive unbalanced current component is extracted from the quadrature currents，enabling the separation and accurate calculation of the load unbalanced current even when the supply voltage is asymmetrical. Experimental results demonstrate that the proposed technique achieves accurate real-time calculation of load unbalance currents under unbalanced grid-side voltages directly in the time domain.