Computation of the dielectric stresses produced by PWM type waveforms on medium voltage transformer windings

In this work, the stresses produced by pulse width modulator (PWM) type excitation on the dielectric system of a medium voltage transformer winding is analyzed. For that purpose, electrostatic and transient simulations are performed. First, the turn-to-turn capacitance matrix of a transformer winding is computed by means of electrostatic simulations using the finite element method. Then, a lumped (RLC) winding model is constructed and solved by means of a frequency domain method (the numerical Laplace transform) to obtain the transient response of the winding. From such a response, the distribution of the dynamic potential and the corresponding dielectric stresses are obtained.