Problem. Substations 10(6)/0.4 kV built into residential buildings create a magnetic field with magnetic flux density of more than 10 μT in nearby residential premises, which is a danger to the health of the population and makes the study of this magnetic field relevant for the development of methods for its protection. The main source of the substations external magnetic field is their low-voltage current conductor, the contribution of which to the total level of the magnetic field is more than 90 %. Multi-dipole mathematical models, which have a clear physical interpretation, are a promising method of modeling the substations magnetic field, which is important for the further development of methods of population protection. The purpose of the work is to modify the well-known multi-dipole model for calculation based on it with a limited error of the external magnetic field of current conductors of built-in substations that are close to residential buildings at a distance of up to one meter. Methodology. A modified two-phase multi-dipole mathematical model of the main source of the external magnetic field of substation – its three-phase low-voltage current conductors – is proposed, which, unlike the existing model, is based on a two- you to halve the distance to the area of calculation without increasing the error. Verification. An experimental verification of the modified two-phase multi-dipole model of the magnetic field of a three-phase 100 kVA transformer substation on its full-scale physical model was carried out, and the results of the experiment were presented, confirming the coincidence of the calculation and the experiment with a spread of no more than 7 %.