A complete PSpice model of the LHC main dipole circuit is presented. The results of the simulations of the voltage transients occurring in the circuit after the switch-off of the power converter and after a fast power abort (power converter switch-off + switch opening) show very good agreement with measurements by the quench protection systems (both 'new' and 'old'). The behavior of the so-called unbalanced dipoles, which are oversensitive to any voltage transient, is successfully modeled by assigning a different value to one parameter of the model of each aperture, based on the real behavior observed in the LHC.