The power estimation is performed for a medium/low voltage transformer of a low voltage network. Among the factors to be accounted for in the estimation is the load density and the shape of the fed zone. From variously shaped fed zones that of hexagonal shape compactly covers a greater territory and has better indices as compared with rectangles and triangles. The study is framed on an apt canonical model − a circular fed zone with constant continuous load density. The model can be used for comparison of indices at the discrete load dislocation in hexagonal or squared fed zones, extending the results obtained for a circular zone using relative ratios. The transformer power is determined by the fed zone radius, which has a natural limit, since the voltage deviation for the farthest consumer should not exceed the allowable value. Under these conditions, optimization can be performed by a given load density, changing the radius of a fed zone and the density of current in phase conductors.