Relevance of the work is caused by the need of localize the defects of the transformer windings at diagnosis. It is possible to determine the spatial location of the defects along the transformer winding only if the transformer is considered as a system with distributed parameters. The main aim of the study is to present the transformer winding in the form of distributed electric circuit and to study the transients of such a circuit in two cases, at grounded winding end and at open winding end; to determine primary and steady voltage distribution along the transformer windings at the grounded winding end and open winding end; to search for possible ways to overcome the overvoltage arising along the transformer winding. The aim of the work is to obtain as well the transitional function caused by a unit action, in order to use subsequently the Duhamel integral which allows obtaining the transients in the transformer winding at an arbitrary external action. The methods used in the study are based on equations solution in partial derivatives using Laplace transform and transfer functions. It uses the initial conditions along the transformer winding and the boundary conditions at the ends of the windings. The final solution of partial differential equations is represented as a series, that is in the form of wave superposition with different frequencies. The results. The obtained transfer function of the voltage distribution along transformer windings allows determining: primary and steady stress distribution; over-voltage transient conditions; optimal values of distributed capacitance, and minimizing overvoltage along the winding.