  We investigate thermoelectric transport through a SU(N) quantum impurity in
the Kondo regime. The strong coupling fixed point theory is described by the
local Fermi-liquid paradigm. Using Keldysh technique we analyse the electric
current through the quantum impurity at both finite bias voltage and finite
temperature drop across it. The theory of a steady state at zero-current
provides a complete description of the Seebeck effect. We find pronounced
non-linear effects in temperature drop at low temperatures. We illustrate the
significance of the non-linearities for enhancement of thermopower by two
examples of SU(4) symmetric regimes characterized by a filling factor m: i)
particle-hole symmetric at m=2 and ii) particle-hole non-symmetric at m=1. We
analyse the effects of potential scattering and coupling asymmetry on the
transport coefficients. We discuss connections between the theory and transport
experiments with coupled quantum dots and carbon nanotubes.
