  We model s-wave and d-wave disordered granular superconductors with a
three-dimensional lattice of randomly distributed Josephson junctions with
finite self-inductance. The nonlinear ac resistivity of these systems was
calculated using Langevin dynamical equations. The current amplitude dependence
of the nonlinear resistivity at the peak position is found to be a power law
characterized by exponent $\alpha$. The later is not universal but depends on
the self-inductance and current regimes. In the weak current regime $\alpha$ is
independent of the self-inductance and equal to 0.5 or both of s- and d-wave
materials. In the strong current regime this exponent depends on the screening.
We find $\alpha \approx 1$ for some interval of inductance which agrees with
the experimental finding for d-wave ceramic superconductors.
