LBU Transformers

ABB LBU PPTR

2013-06-05
Page 1 of 6
LBU Instruction
Status of
Issued by: Hoang Sy Hai document: Released
Reviewed by: Vinh VuQuoc Revision: 00
Approved by: JanPeder Dareus Document
Identity No.: 1ZVN469010-614

FINAL OIL FILLING ON SITE – ATMOSPHERIC PRESSURE

1 Responsibility
These instructions are intended for the guidance of personnel who have been trained for, or who
have experience in oil filling process, maintenance of power transformers using mineral oil, silicone
oil or Esther fluid (BIOTEMP®) and servicing of high-voltage electrical power equipment including
the use of good safety practices.
2 Applicability and validity
contained therein. Reproduction, use or disclosure to third parties

This instruction applies to adding top up oil to transformers with a nominal voltage below 200 kV,
We reserve all rights in this document and in the information

shipped with oil nearly up to the cover.

without express authority is strictly forbidden.

Filling to normal oil level can in these cases be done with a filter unit. The quantity of top up oil to
be added in this manner should be less than 16 % of the total oil volume in the transformer.
@ ABB 2004

3 Objective

This instruction applies to adding top up oil to power transformers which are transported and
partially filled with oil under top cover.

4 Definition

QMS: Quality Management System

EMS: Environment Management System

OHS: Occupational Health and Safety

LBU: Local Business Unit

PPTR: Power Product Transformer

: OHS requirement

: Quality requirement

: Environment requirement
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LBU Instruction

: Recommendation

: Attention

5 Equipment

 Oil filter unit with the following requirements:

- The filter could be able to remove particles bigger than 5 micrometers.

- The filter shall have a capacity not less than 3000 liters/hours and the filter with
capacity from 4000 – 6000 liters/hours is recommended.

- The filter should be capable of reducing water content in oil not to above 100 ppm
(at 50 – 80 degrees Celsius) and dissolved gas content to not above 0.2 percent.
contained therein. Reproduction, use or disclosure to third parties

- Temperature range of heaters can be adjustable within 60 – 80 degrees Celsius.

We reserve all rights in this document and in the information

without express authority is strictly forbidden.

- The filter unit should be specifically used for transformer oil ONLY.

- The filter shall be included the suitable oil hoses, connection flanges.
@ ABB 2004

 Storage tank for oil (inside wall has to be painted and rust-free, provided with
desiccant breather and specifically use for transformer oil only).

 Dried air/nitrogen cylinder equipped with pressure regulator, suitable pressure gauge,
connection flange, and hose.

 Suitable tools.

6 Content

6.1 Health and Safety

The compliance with Instructions:
1/ Service Occupational Health & Safety (OHS) Induction Training Policy, Document identity
No.2NAA000020
2/ Health and Safety Requirements for Active Part Drying and Oil Treatment, Document identity
No.1LAA000071
This Guide has been developed by ABB. It sets the minimum requirements for ABB operations. If
higher performance is required by national regulations and or customers then that higher requirement
should be followed.

6.2 Environment
In addition to complying with the local relevant environment rules & regulations, team leader /
supervisor and operator should follows:
* Before performing the work:
- Identify Environmental problems can arise during operation, especially oil leakage and/or spill
during & after the oil filled process.
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LBU Instruction

- Understand the plan, how to handle in case of environmental accidents occur, especially in the
case of oil leakage and spillage.
- Ensure availability of equipment troubleshooting spilled oil and chemicals (eg: Bounded pallet,
sand, sawdust, rags or dedicated equipment to prevent oil spill and chemical - Spill kit ...).
- Make sure the devices are in good operating condition and easily accessible.
- Understand how to use these devices.
* During and after the process:
- Make sure the device is no longer leaking oil or is no longer able to leak into the environment.
* In the case of Environmental problems occur:
- Is necessary to comply with zoning action, minimizing the impact on other areas as well as
sewer pipe system.
- Quickly use of the facilities and equipment were prepared to troubleshoot.
- The facilities and equipment used during and after the process of troubleshooting environment
classified according to the classification of waste, especially hazardous waste classification.
- Notify the persons in charge of Environment on environmental incidents occur.
6.3 Work instruction
6.3.1 Supply of the oil. Quality requirements, and cleanliness
contained therein. Reproduction, use or disclosure to third parties
We reserve all rights in this document and in the information

The necessary quantity of top up oil for the final filling may be shipped with the transformer, or
without express authority is strictly forbidden.

may be procured locally. If the Customer provides the oil, prior approval for use must be obtained
from ABB and the characteristics must meet the requirements which indicated in instruction
“Instruction for receiving and handling transformer oil on site-Quality control”.
@ ABB 2004

Competent supervision and a responsible work force are necessary requirements. Industry
standard cleanliness and personal safety precautions must be observed in accordance with
common sense and local regulations.

Transformer internal components must be free of contamination and dry for effective and safe
operation. These conditions, established during manufacture and sustained during transport must
be maintained during oil filling and assembly.

The top up oil is typically supplied in drums but may be supplied in a tanker if the required quantity
is large enough.

The drums (or tanker), all hoses, pumping equipment, valves and filters must be for the exclusive
use of the transformer oil or have been meticulously cleaned and rinsed. Failure to ensure
pristine oil and equipment puts at risk the viability of the transformer operation.

Cleaning processing equipment typically used for mineral oil:

For transformers using the Esther fluid (BIOTEMP®), the instruction for cleaning oil filter, hoses
which typically used for mineral oil should be applied as below:

In order not to contaminate the ester fluid, it is important to thoroughly flush the processing rig
before filling the transformer. It is recommended that the processing equipment is flushed with
400 gallons (approximately 1540 liters) if the ester fluid. The flushing should be performed in two
stages. First the mineral oil is flushed out by using 200 gallons (770 liters) of the ester fluid. All
hoses that are used for filling and draining the transformer are to be connected to the rig before
the flushing. A small amount of the first 200 gallons should be run through the system; the oil is
then removed and stored in barrels for DISPOSAL. The process should be repeated until all 200
gallons of the ester fluid are used up. Next a new filter should be installed prior to the second step
which involves flushing the complete system with the remaining 200 gallons of the ester fluid. All
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LBU Instruction

the oil used for the cleaning is to be stored in barrels and disposed of. The same process is to be
used to clean the system (this time with mineral oil as the flushing oil) for use with mineral oil if the
rig is to be used to fill a mineral oil transformer after filling an ester transformer.

Oil in drums or tanks, as delivered, should never be directly filled into the transformer, but always
pumped through a filter unit. It is important that clean and dry filters are used. A small sump
quantity should be left unused in the drums or tank.

Oil from delivered drums should be filled into storage tank for oil circulation before being filled into
transformer.

The oil quality in delivered drums (or tanker) and in storage tank before being filled into
transformer has to meet requirements in “Instruction for receiving and handling transformer
oil on site – Quality control”.

6.3.2 Topping up instruction

When a transformer has been shipped more or less complete, and with oil nearly up to the cover,
the following procedure is used to complete the oil volume. A filter unit must be used.
contained therein. Reproduction, use or disclosure to third parties
We reserve all rights in this document and in the information

without express authority is strictly forbidden.

@ ABB 2004

Figure 12.3

The oil, stored in drums or in a storage tank, is pumped through the filter

6.3.3 Transformers with conservator design

For transformers designed with a conservator, the top up oil should first be pumped into the
conservator with the valve between the conservator and the main tank closed.

Open the airvent screws on the top of main conservator and blind flange at bottom end of air
breather pipe. Make sure that equalizing valve between rubber air cell and main conservator is
closed status to avoid oil entering into rubber air cell from the main conservator.
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LBU Instruction

When the conservator is 3/4 full, stop the pumping and open all the bleeder valves for air escape
from main tank during oil flowing from the conservator, the valve between the conservator and the
main tank, then slowly allow the oil into the transformer.

The oil must be introduced slowly to limit turbulence and air bubbles from going into the windings.
Repeat this procedure until the proper oil volume is attained. (See also para. 6.3.5 Filling coolers
and radiators).

When oil filling completed, all bushings, turrets and other devices that require bleeding must be
bled to avoid trapped air pockets, then sealed.

6.3.4 Transformers with sealed tank design

Sealed tank designs are often shipped overfilled with the quantity of oil required to fill the cooling
equipment.

The data on the oil volume and whether additional oil needs to be added will be shown on the
outline or shipping drawing.
contained therein. Reproduction, use or disclosure to third parties
We reserve all rights in this document and in the information

For sealed tank designs, the top up oil should be added through the top filter connection valve. The
oil must be introduced slowly to limit turbulence and air bubbles from going into the windings.
without express authority is strictly forbidden.

Obtain a test sample from the main tank and test for dielectric strength.
@ ABB 2004

Purge the gas space in the transformer and seal the tank at atmospheric pressure (zero gauge).

6.3.5 Filling coolers and radiators

Fill the cooling equipment by opening the upper valves between the cooler or radiator and the main
tank and bleed the air through the top vent plug from each cooler or radiator.

Ensure that the oil level in the main tank is always above the top of the core and all
insulation material.

After completing assembly, check that the oil is at the correct level, being careful to make the
appropriate correction for the oil temperature if different from 25 °C.

For transformers that shall be pressurized, verify that all accessories in contact with the oil or oil
preservation system have been assembled before pressurizing the transformer.

After the oil filling procedure has been completed, the transformer should be left at least twelve
(12) hours (mineral oil) or thirty – one (31) hours (Ester fluid (BIOTEMP®)) before energization.
Impregnation time is applied to transformers with nominal voltages less than 150 kV.

6.3.6 Final oil circulation and air bleading

After oil filling is completed. The final oil circulation should be done as follows:

1. The transformer is connected to the filter in a loop through the upper and lower filtering valves.
The direction of circulation shall be from the filter to the transformer at the top and from the
bottom of the transformer to the filter.

2. The temperature of the oil from the filter to the transformer shall be 60 to 80 °C.
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2013-06-05
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LBU Instruction

3. The circulation shall proceed until a volume of oil has passed through the loop corresponding
to 2 times (estimated) the total oil volume in the tank. (At freezing ambient temperatures the
circulation time is increased thus; circulate 3 times the volume at temperature down to minus
20°C, and increase to 4 times below that temperature). In fact, the number(s) of oil circulation
cycle should be calculated case by case.

Air bleeding from conservator by loosening air vent plugs on the top of conservator then filling dry
gas (air or nitrogen) to rubber bag through the air breather pipe with pressure does not exceed
0.13 bars (0.013 Mpa). Tighten the air vent plugs simultaneously when oil comes out.

For air bleeding from bushings and others, refer to their instruction leaflets accordingly.

7 References

No. Document
contained therein. Reproduction, use or disclosure to third parties
We reserve all rights in this document and in the information

1ZBA4601-214
without express authority is strictly forbidden.

(Rev. D)
Final oil filling on site – Atmospheric pressure
@ ABB 2004

8 Revisions

Rev. Index Rev. Date Revision content

2013-06-05 First issue