The theory of the distribution of electric field in the insulation of DC cable
is investigated based on Gauss law, and the expression of the electric field is acquired
in this paper. The distribution of electric field is investigated for the real ±200 kV and
±320 kV DC cables based on the distribution theory. The influence of resistivity on the
electric field in insulation of DC cable is analyzed, and the relationship between DC
electric field and AC electric field of the cable insulation is studied. It indicated that
the position of the maximum field is changed from the outer insulation to the inner
insulation, and the distribution of DC field and AC field tends to be consistent with
the increasing of resistivity.