The eddy currents' distribution is investigated during a transient process in a superconducting magnet system. We have applied a numerical method based on an integral approach. In such a method, only the coils of the magnet system without the air embedding are discretized. Such integral approach leads to the full matrices and consequentially to large computational requirements. There are techniques, which generate less dense matrices by introducing groups of long-range interactions. We have applied a similar technique based on equivalent currents in the coils.