2 Safety
Maschinenfabrik Reinhausen GmbH 2020
19
4983703/01 EN
VACUTAP
®
VV-Ex
2.5.2.3.1 Dehydrating breather
The oil conservator must be equipped with a dehydrating breather in accor-
dance with VDE 0532-216-5 with downward-leading outlet and a protection
degree of at least IP66 in accordance with IEC 60529.
2.5.2.3.2 Level indicator
The oil conservator must have a level indicator from which the minimum oil
quantity required and the maximum quantity permitted, as well as the current
oil level, can be read.
2.5.2.3.3 Level monitoring
The oil level in the oil conservator must be monitored at all times during op-
eration. Therefore, loop the signaling contact for falling below the minimum
oil level in the on-load tap-changer's oil conservator to the tripping circuit of
the circuit breaker so that the circuit breaker will immediately de-energize the
transformer when the oil level in the oil conservator falls below this minimum.
2.5.2.3.4 Insulating oil to be used
When filling the diverter switch oil compartment and its oil conservator, use
only new mineral insulating oil for transformers in accordance with IEC
60296 (Specification for unused mineral insulating oils for transformers and
switchgear) or synthetic ester in accordance with IEC 61099 (Specifications
for unused synthetic organic esters for electrical purposes).
2.5.2.3.5 Checking the quality of the insulating oil in the Ex transformer
During the tap changes, polarity sparks (low energy) may occur at the tap
selector of the on-load tap-changer in the transformer tank. In this regard,
observe Section 5.1.6 and 5.1.7 in the on-load tap-changer standard IEC
60214.
Therefore, check the quality and dielectric strength of the insulating oil in the
transformer tank on a regular basis and comply with the service intervals for
the oil change.
