23-08-2012, 03:30 PM
User's Manual Assembly and Energizing For Power Transformers
User\'s Manual.pdf (Size: 232.69 KB / Downloads: 290)
Objective
This instruction indicates the order of the activities to accomplish in the assembly and
energizing of power transformers.
Description of the Manual
The recommendations, instructions and procedures here contained will give you a guide
to accomplish labors of installation or assembly and implementation or energizing of a
power transformer. This information is not the only one requirement to the transformer
operates satisfactorily. It is required to count firstly on qualified personnel and tools and
equipment designed for this purpose.
The assembly order of the transformer
It is important to remember that these instructions are general and for some transformers
is possible that certain instructions and/or recommendations will not be applicable. After
assembly of the transformer, make sure to check.
Recommendations during arrival at installation site
Some times the transformers are transported disassembled and in several sections such
as the main tank, the insulators, the conservator tank, the radiators and other parts. The
disassembled components are placed in crates or in boxes. These parts must be
matched against the supplied packing list.
Immediately after arriving to the assembly site, a revision must be performed in order to
find any damage that may have happened during transportation, and to verify if there are
any missing pieces. If the damages are found, please issue a claim as soon as possible:
• Checking for gas pressure
In order to avoid any humidity from entering the main tank, it is filled with dried nitrogen
gas (approximately 0.2 kg/cm² to 20°C). Remove the protective cover from the pressure
gauge mounted on the tank, open the connection valve and check the pressure of the
gas. After checking, close the valve tightly. A positive reading will means that no water or
air has leaked to the interior of the tank. If the needle indicates zero, there may be water
inside. In this case, measure the isolation resistance of the winding in order to establish
the degree of humidity that has penetrated the transformer and to take the necessary
corrective actions.
Storage
After a transformer has been received at its final destination, it is advisable to put it (full of
oil) on its permanent place, even if it is not going to be placed in operation immediately. If
this is not possible, the transformer has to be placed in a dry place and the transformer
must be filled with oil. If the unit is going to be located outdoors, the water vapor will
condense inside the tank, due to the variations in temperature and humidity. This will be
absorbed by the winding and it will be necessary to dry the unit before putting it on
operation. Therefore, it is preferable to place the transformer in a place where the
temperature is slightly high and stable.
Storage of insulating oil
Insulating oil will be kept exclusively in clean containers and will be protected against
humidity by placing the containers in a place where the temperature is maintained
unchanged and on horizontal position. It will be avoided carefully any mixture with other
liquids (oil for cables, lubricating and heating) or with solid particles. Small quantities of
impurities can highly alter the qualities of the insulating oil. All the containers for storage
are carefully checked and a detailed record will be kept of cleanliness and of perfect
impermeability. It will be the responsibility of the selling company whenever possible to
wash the dirty and/or used containers.