Optimizing Relative Height of Transformer Windings for Least Electromagnetic Forces

In distribution transformers helical winding is generally used for the LV side-that carries high current. The helical windings can be of multiple layers. The turn of a helical winding is wound in the axial direction along the helical line with an inclination A one-layer winding it starts at the bottom of the winding and finishes at the top. A two-layer helical winding turns are also wound along a helical line. The layer-one forms the outer/front coil and the layer-two forms the inner/back coil. The conductor passes from outer layer one to the inner layer two at the bottom both the start and the finish of the winding are at the top. The asymmetry caused by helical winding has an effect on the electromagnetic forces produced. Tappings also cause asymmetry. There is a need to find the the optimum relative height of LV and H V winding such the short circuit forces and the resulting mechanical stresses are least in a transformer having helical LV winding.