8 Maintenance and inspection
44 10014218/00 EN
Maintenance
The device does not require maintenance.
Inspection
Depending on the conditions of use of the device and the national regula-
tions in the respective country of use, the transformer manufacturers can
specify different inspection intervals.
► Observe the inspection intervals defined in CIGRE Publication No. 445
"Guide for Transformer Maintenance" or the inspection intervals specified
by the transformer manufacturer.
During each transformer inspection, check the following:
1. Check the external condition of the device for contamination, damage
(e.g. broken glass, electrical connection) and corrosion.
2. Vent the device [►Section 6.1, Page 35].
3. Check the tightness of the flange connection [►Section 5.1, Page 22].
4. Check that the device is functioning correctly [►Section 6.3, Page 37].
8.1 Draining the insulation fluid – device version without bypass
If you have to drain insulating fluid from the device for inspection work or
maintenance work on the transformer, proceed as follows:
1. Close the isolation valves to isolate the device.
2. Open the drain valve.
3. Unscrew and remove the drain plugs (wrench size10).
ð The insulating fluid flows out of the device.
4. Capture the insulating fluid in a suitable container.
5. Tighten the drain plugs (wrench size10, 5Nm).
6. Close the drain valve.
7. If necessary, remove the device.
8.2 Draining the insulation fluid – device version with bypass
If you have to drain insulating fluid from the device for inspection work or
maintenance work on the transformer, proceed as follows: