Load imbalance in a three-phase electricity distribution system can lead to the emergence of excessive neutral current, increased power losses, and decreased efficiency of the distribution system. This study aims to analyze the effect of load imbalance on neutral flow and the magnitude of losses at Substation Seri.01 PT PLN (Persero) ULP Nusaniwe, both before and after load balancing. The methods used include direct measurements in the field and simulation using ETAP software. The results of the analysis calculation at Substation Seri.01 show that before the load balancing was carried out, the percentage of load imbalance in department 1 was 75.2%, department 2 was 50.2%, department 3 was 42.3% and department 4 was 46.2%, this condition has passed the applicable standard in accordance with SPLN No. 017 of 2014, namely the load imbalance exceeding 25% must be corrected. This imbalance condition also causes a large neutral current, which reaches 117.4 A which results in a power loss of 2.75%. After weight balancing, the imbalance value in each major dropped drastically, in major 1 to 1%, in major 2 to 5.1%, in major 3 to 1.7% and in major 4 to 2.7%. This small imbalance condition results in a drastic reduction in neutral current to 16.2 A and the percentage of power loss is also reduced to 0.54%. In conclusion, load imbalance has a significant impact on the performance of electrical power distribution, and load balancing has been proven to minimize neutral current and power loss.