3 Non-ceramic apparatus evaluated
The polymeric apparatus evaluated in this project are
two substation surge arresters and two bushings. Table 3
includes the main characteristics of the equipments and
Fig. 1 shows the set-up for the salt-fog chamber. These
apparatus voltage classes are used in 115 kV ac systems.
Therefore these equipments are evaluated under this voltage
level (66.4 kV phase-to-ground). Each bushing is mounted
on a small steel tank, and both the bushing and the tank are
pressurised with nitrogen to avoid moisture ingress into the
tank. The test voltage of 66.4 kV phase-to-ground is applied
at the upper flange, and the tank is grounded