The research develops a method to simulate transients in transformer windings using a model of multiconductor transmission line. To solve the Telegrapher's Equations describing the propagation of waves of voltage and current is used a Method in Time Domain, the Method of Characteristics. Computational techniques developed to simulate electromagnetic transients in transmission lines can be classified into two groups: techniques in frequency domain and techniques in time domain. The techniques in frequency domain have a very good numerical accuracy and easily consider the frequency dependence of the parameters of the line. On the other hand, the techniques in time domain are more suitable to solve real-time simulations, and transmission lines with nonlinear parameters (voltage and / or current dependent).