instruction manual - BHEL Bhopal

2.2 STORING OF TRANSFORMER/REACTOR DESPATCHED FILLED WITH
NITROGEN
2.2.1 STORING BEFORE COMPLETE ASSEMBLING
The storing place should be easily accessible for inspection and
maintenance of the transformer. The bedding for the equipment should be
larger than its bottom surface and dimensioned for the load. The transformer
is placed on boardings or beams so that good ventilation is obtained underneath
the transformer bottom.
Before storing, the transformer is inspected according to directions in
Clause 2.1 "Reception and assembling of transformer/reactors despatched
partly dismantled and filled with nitrogen".
A transformer without remarks may be stored up to 3 months after
arrival at the site without oil-filling. During the storing time, the inert gas
(nitrogen) filling shall be maintained and pressure regulated, so that exposure
of active part to atmosphere is avoided.
If the storage time is judged to exceed 3 months, the transformer should
be provided with oil conservator including oil-level indicator and breather, and
oil-filled according to Clause 2.5. "Oil filling under vacuum". Certain valves
must be re-mounted to enable the oil-filling being carried out. Furthermore, at
the time at oil-filling of a completely assembled transformer, certain rules in
Clause 2.5 & 2.6 must be complied with absolutely.
Wherever possible it would be most desirable to keep the transformer
energized even at a low voltage so that its temperature is higher than the
ambient temperature. The low voltage may be applied under open circuit or
short circuit conditions. It may be ascertained whether partial cooling is required
in such a case. The oil quality should also be periodically monitored. If for
some reason, oil filling cannot be carried out after a storage period longer than
3 months, the nitrogen pressure shall be maintained and supervised carefully.
If the storage time without oil exceeds 18 months BHEL should be consulted
about measures to be taken.
2.2.2 STORING OF COMPONENTS AND ACCESSORIES BEFORE
COMPLETE ASSEMBLING
Independent of the duration of the storing time, the directions below
apply for dismounted components and accessories, as well as for material to
be used in connection with the assembling work.
(a) Storing indoors
In such a room, the following articles should be stored:
(i) Insulation material as paper, pressboard, bakelite, wood, cotton tape
etc.
(ii) Insulated details as paper-insulated conductors, pressboard insulated
shielding bodies etc.
(iii) Chemicals as solvents, glues, varnishes, hardeners etc.
(iv) Breathers, drying agents.
(v) Terminal boxes, connection boxes, control cabinets.
(vi) Gas relays, oil-level indicators, thermometers, pressure valves etc.
Prepared By Samvet Lahari, Bhopal. Phone- 5277412