  Topological/perfectly-transmissive defects play a fundamental role in the
analysis of the symmetries of two dimensional conformal field theories (CFTs).
In the present work, spin chain regularizations for these defects are proposed
and analyzed in the case of the three-state Potts CFT. In particular, lattice
versions for all the primitive defects are presented, with the remaining
defects obtained from the fusion of the primitive ones. The defects are
obtained by introducing modified interactions around two given sites of an
otherwise homogeneous spin chain with periodic boundary condition. The various
primitive defects are topological on the lattice except for one, which is
topological only in the scaling limit. The lattice models are analyzed using a
combination of exact diagonalization and density matrix renormalization group
techniques. Low-lying energy spectra for different defect Hamiltonians as well
as entanglement entropy of blocks located symmetrically around the defects are
computed. The latter provides a convenient way to compute the $g$-function
which characterizes various defects. Finally, the eigenvalues of the line
operators in the "crossed channel'' and fusion of different defect lines are
also analyzed. The results are all in agreement with expectations from
conformal field theory.
