  We discuss the role of direct Coulomb interaction on the bulk insulator of
the integer quantized Hall effect that bridges the topological insulators and
the conductance quantization. We investigate the magneto-transport properties
of a two-dimensional electron system in the bulk, numerically, utilizing the
self-consistent Thomas-Fermi-Poisson screening theory. Topologically distorted
Hall bars with and without potential fluctuations are considered that comprises
two identical inner contacts. Although these contacts change the topology, we
show that quantized Hall effect survives due to redistributed incompressible
strips on account of interactions. It is shown phenomenologically that the
impedance between these contacts can be obtained by a minimal transport model.
An important prediction of our self-consistent approach is a finite impedance
between the inner contacts even in the plateau regime, where the maximum of the
impedance decreases with increasing temperature.
