  We study low-energy properties of the N-fold degenerate Anderson model. Using
a scaling that takes u=(N-1) U as an independent variable in place of the
Coulomb interaction U, the perturbation series in U is reorganized as an
expansion in powers of 1/(N-1). We calculate the renormalized parameters, which
characterize the Kondo state, to the next leading order in the 1/(N-1)
expansion at half-filling. The results, especially the Wilson ratio, agree very
closely with the exact numerical renormalization group results at N=4. This
ensures the applicability of our approach to N > 4, and we present highly
reliable results for nonequilibrium Kondo transport through a quantum dot.
