5 Mounting
Maschinenfabrik Reinhausen GmbH 2019
48
6107891/02 EN
ECOTAP
®
VPD
®
5.6 Filling transformer with oil
For the oil filling of the transformer, use new mineral insulating oil for trans-
formers as per IEC 60296 (Specification of unused mineral insulating oils for
transformers and switchgear).
If approved by the transformer manufacturer, synthetic ester liquids as per
IEC 61099 (Specification for unused synthetic organic esters for electrical
purposes) or natural ester liquids as per IEC 62770 (Specification for unused
natural esters for transformers and similar electrical equipment) can be used
as alternatives.
Contact Maschinenfabrik Reinhausen GmbH if you want to use an alterna-
tive insulating fluid.
Observe the permitted temperature range of the transformer oil in the "Tech-
nical data" [
Section 11.2, Page 65] chapter.
NOTICE
Damage to the on-load tap-changer!
If a transformer is not completely filled with oil, the on-load tap-changer may
be damaged!
► Before commissioning the on-load tap-changer, completely fill trans-
former with oil.
► If using the special design of the 3-phase on-load tap-changer for her-
metic transformers with gas cushion, be sure to observe the oil fill details
on the supplied dimensional drawing.
1. Completely fill transformer with oil.
2. Take oil sample from transformer.
3. Record temperature of oil sample just after sample is taken.
4. Determine dielectric strength and water content at an oil temperature of
20°C ± 5°C. The dielectric strength and water content must comply with
the limit values stated below:
U
d
H
2
O
When commissioning the
transformer for the first
time
> 60 kV/2.5 mm
< 12 ppm
Table 7: Limit values for mineral insulating oil (dielectric strength U
d
measured in accordance
with IEC 60156)