Numerical simulation of a power transformer using 3D finite element method coupled to circuit equation

Most of the electromagnetic devices work connected to an electric circuit and their numerical simulation in 3D leads to a large number of unknowns. To deal with these problems we propose to use the T/sub 0//spl Omega/ formulation and describe the way of coupling magnetic and electric circuit equations. The coupling is obtained by expressing the electric vector potential T/sub 0/ from the current and the flux of induction and from the magnetic scalar potential /spl Omega/. To consider the magnetic nonlinearity we use the Newton-Raphson procedure. This formulation is used to model a 100 MVA power transformer short circuit test in the transient state. The same device is studied at no-load.>