This technical report presents the validation process for the ETAP Unbalanced Load Flow program, which includes over 550 test case scenarios executed prior to each release. The report specifically compares the results of the ETAP Unbalanced Load Flow against a published IEEE 13-bus feeder system. It details the methodology used to model the unbalanced distribution system, including the conditions under which the equivalent system was designed. The report outlines the comparison of bus voltages, angles, and current flows across phases, indicating that the differences in results are consistently less than 0.5%. Several tables provide detailed comparisons of bus voltage magnitudes and angles, as well as current flows, highlighting the precision of ETAP's modeling against the IEEE benchmark. The document is intended for internal use and emphasizes the proprietary nature of the information contained within.