  In the work, a modified effective medium theory is constructed for
calculating the effective properties of thermoelectric composites with
different values of percolation thresholds. It is shown that even at
concentrations beyond the critical region, the threshold value is essential for
determining the effective properties. Two fundamentally different cases of a
set of local properties of the composite are considered. In one of these cases,
the conductivity and thermal conductivity of one of the phases is
simultaneously greater than the conductivity and thermal conductivity of the
other phase. The second, anomalous case, when the electrical conductivity of
the first phase is greater than that of the second, but the thermal
conductivity of the first phase is less than that of the second, shows unusual
concentration behavior of effective conductivity, i.e. with an increase in the
well-conducting phase, the effective conductivity shows a decrease (rather than
growth as in the standard case), which at goes over to growth.
