MR VACUTAP VM I 1002, Operating Instructions Manual, Page: 68 / 82

8 Technical data
Maschinenfabrik Reinhausen GmbH 2020 68 4360571/02 EN VACUTAP
®
VM
®
8.5 Limit values for dielectric strength and water content of
insulating fluids
The following tables specify the limit values for dielectric strength (measured
in accordance with IEC 60156) and water content (measured in accordance
with IEC 60814) of insulating fluids for the VACUTAP
®
on-load tap-changer.
The values have been determined based on IEC 60422, IEC 61203 and
IEEE C57.147.
Limit values for insulating fluids in ac-
cordance with IEC 60296 U
d
H
2
O
When commissioning the transformer for
the first time > 60 kV/2.5 mm < 12 ppm
During operation > 30 kV/2.5 mm < 30 ppm
After maintenance > 50 kV/2.5 mm < 15 ppm
Table 25: Insulating fluids in accordance with IEC 60296
Limit values for natural esters in ac-
cordance with IEC 62770 U
d
H
2
O
When commissioning the transformer for
the first time > 60 kV/2.5 mm ≤ 100 ppm
During operation > 30 kV/2.5 mm ≤ 200 ppm
After maintenance > 50 kV/2.5 mm ≤ 100 ppm
Table 26: Natural esters in accordance with IEC 62770
Limit values for synthetic esters in ac-
cordance with IEC 61099 U
d
H
2
O
When commissioning the transformer for
the first time > 60 kV/2.5 mm ≤ 100 ppm
During operation > 30 kV/2.5 mm ≤ 400 ppm
After maintenance > 50 kV/2.5 mm ≤ 150 ppm
Table 27: Synthetic esters in accordance with IEC 61099