Large signal nonlinear model of anisotropic transformers for nonsinusoidal operation. II. Magnetizing and core-loss currents

For pt.I see ibid., vol.6, no.1, p.174 (1991). No-load currents and voltages of saturated single-phase transformers are computed based on given lambda -i and harmonic core-loss characteristics. A circuit analysis approach is used to satisfy the nonlinear equations involved in an iterative manner. The theoretical and experimental analyses confirm that for the calculation of the iron-core losses under nonsinusoidal operating conditions the principle of superposition cannot be applied: the iron-core losses are dependent not only on the amplitudes of the fundamental and the harmonics of the flux density, but also on the phase shifts of the harmonics with respect to the fundamental. For the computation of the ohmic losses at no-load the skin effects within the windings are taken into account. To confirm the validity of the computed results some of them are compared with measurements.>