A new boundary element technique to transient non-linear low penetration problems of multiconductor systems

This paper describes a time domain boundary element formulation for calculation of eddy currents in a system of conductors of magnetic material due to the passage of short current pulses. The perturbation method is applied to derive the implicit time domain non-linear surface impedance boundary condition (SIBC) for the normal component of the magnetic field (magnetic induction) on the surface of the conductor of homogeneous isotropic magnetic material with an arbitrary BH-curve. Then the SIBC is coupled with the surface integral equation for the scalar magnetic potential given by the boundary integral equation method. The formulation developed is applicable to 3-D problems as well as 2-D problems. It Is shown that no computational difficulties arise compared to solving the problem under the assumption that the field does not penetrate into the body (static problem). A numerical example is considered.