Simulation of multilimb power transformers in the harmonic domain

The multilimb three-phase transformer is modelled in the harmonic domain, a new frame of reference which allows the explicit representation of cross-couplings between phases and between harmonics. The branches of the magnetic equivalent circuit are independently associated with magnetising characteristics representing the saturation at different core regions. Transformer leakage admittance and mutual admittances between windings are also represented. The periodic behaviour of the transformer is obtained by combining its nonlinear magnetic components, represented by a harmonic Norton equivalent, with the linear part of the network in a unified iterative solution.