MR VACUTAP VMS - Inspection

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7 Maintenance

Maschinenfabrik Reinhausen GmbH 2020 475993419/02 EN VACUTAP

VMS

7.1 Inspection

Monitoring the on-load tap-changer and motor-drive unit is limited to occa-

sional visual checks of the on-load tap-changer head, protective relay and

motor-drive unit, as well as monitoring the quality of the insulating fluid. For

efficiency reasons these visual inspections can be combined with the usual

checks on the transformer.

Check the following:

Interval Action

Annually Check door seal, cable bushings, and ventilation of protective

housing of motor-drive unit/control cabinet.

Annually Check sealing points of on-load tap-changer head, protective

relay, and connected pipes.

Annually Check correct functioning of the installed electrical heater in

the protective housing of the motor-drive unit/control cabinet.

Annually Check correct function of protective relay [►Section 4.1.4,

Page 35].

Annually Check perfect condition of the silica gel breather for the on-

load tap-changer oil conservator.

Every 2 years Check the quality of the insulating fluid of on-load tap-chang-

ers that are installed in positions other than the neutral point of

windings (Class 2 in accordance with 60214-1).

1. Take a sample of insulating fluid from the oil compartment.

2. Record the temperature of the sample (insulating fluid) im-

mediately after the sample is taken.

3. Determine dielectric strength and water content at an insu-

lating fluid temperature of 20°C ± 5°C. The dielectric

strength and water content must comply with the limit val-

ues specified in the technical data.

4. If the limit values are not complied with, change the insulat-

ing fluid in accordance with the "Changing the insulating

fluid" section.

Every 7 years Check the quality of the insulating fluid of on-load tap-chang-

ers that are installed at the neutral point of windings (Class 1

in accordance with 60214-1).