the finite element method through software Comsol Multiphysics
® 4.4. The maximum electric field appears in the seat area of
the hook for phase A, since the instantaneous maximum peak
voltage is considered on this conductor. The maximum electric
field is 4.3 × 105 V/m when the voltage is 18.78 kV (phase-toground
peak voltage of a 23-kV system). Similar values are
present in the interfaces of phases B and C when they reach
the instantaneous peak voltage. The covered conductors have
a diameter of 0.026 m, with only one 0.004-m-thick covering
layer; the permittivity of the spacer and covering layer of the
conductor was considered the same (εr = 3). Although the magnitude
of electric field is not large enough to produce surface discharges
under these conditions, the electric field is considerably
increased when conductive pollution is deposited in the spacer
and cable, as it will be shown in the next section