This document provides details on routine testing and maintenance services for transformers. It lists various tests and services conducted before and after overhauling a transformer to improve its performance and efficiency. These include routine testing of components like Buchholze relays, OTI/WTI meters, radiators, conservator tanks and maintenance of parts like the main tank, core and windings. The aim is to check operation and insulation, calibrate instruments, replace gaskets and clean components to enhance the transformer's lifespan.

2.  Over all scope of work:-
 Transformer Routine testing
 Buchholze Relay Servicing and testing
 OTI /WTI testing and calibration
 Radiators maintenance
 Conservator Tank maintenance
 Oil Treatment
 Main tank and cover maintenance
 OLTC Maintenance
 Active part Maintenance

3. We are providing routine site testing before and after
overhauling to ensure Improvement of transformer
performance and quality. Routine testing of
transformer gives us a brief idea about its internal
heartiness and efficiency. We are providing all tastings
with suitable approved and calibrated testing
equipments and appropriate method as per Indian
standards. We are providing approved testing
certificate which is suitable for local energy suppliers
like GETCO, MSEB.. Etc.
Sr.No Name of Testing Purpose of Testing
Before Overhauling After Overhauling
1 Voltage ratio test To check present Voltage regulation To check Improvement in Voltage
regulation
2 Magnetic balance test To check present flux distribution in
core.
To check Improvement of flux
distribution in core.
3 Vector Group To verify Vector Group of Transformer
4 IR & PI value Test To check present winding insulation
resistance value.
To check improvement in
winding insulation resistance
value.

4. Buchholze relay is known as heart of transformer it is mounted
in between transformer main tank and conservator tank, its
function is to give alarm and tripping due to air lag in it at time
of fault generation. Healthiness and effectiveness of Buchholze
relay is most important. We are providing following services
regarding Buchholze relay in overhauling process to improve its
life and service.
Sr.No Service Benefit
1 Gasket replacement of Buchholze relay top
and bottom joint.
To avoid oil leakage from joint.
2 Gasket replacement of air realized and oil
drain plug
To avoid oil leakage from air realized and oil drain
plug.
3 Testing of mercury switch To check healthiness of Buchholze relay
4 Tightening of internal connection stud To prevent if from sparking.
5 Checking of Buchholze relay protection
system
a) To ensure healthiness of protection system of
Buchholze relay including circuit breaker,
enunciator and indicators.
b) Physical Checking of control cable to prevent
from earth fault and leakage.

5. OTI/ WTI are use for measurement of oil and winding
temperature respectively. Precision in temperature indication is
depends on healthiness of OTI and WTI meters. We are providing our
finest services during
overhauling to improve its effectiveness and efficiency.
OTI and WTI gives signal of alarm and trip signals to protection system
at the time of temperature rise beyond its set value.
Sr.No Services Benefit
1 Calibration of OTI/WTI To ensure its accuracy.
2 Testing of mercury switch To ensure healthiness of mercury switch.
3 Testing of OTI/WTI protection system a) To ensure healthiness of protection
system of OTI/WTI including circuit
breaker, enunciator and indicators.
b) Physical Checking of control cable to
prevent from earth fault and leakage
4 Setting of temperature for alarm and
tripping
To prevent transformer from over lading
and over heating which are main
reasons of transformer failures.

6. Radiators are most important part of transformer. Proper
designing and provision of radiators improves
transformer cooling so ultimate loading capacity and
life of transformer improves automatically. Internal
cleaning and maintenance of radiators prevents
overheating and oil leakage.
Sr.No Services Benefit
1 External cleaning of radiators and all joints. To improve its rusting and dusting resist
capacity.
2 Gasket replacement of Air realized and oil
drain valve of radiators
To make them free from leakage.
3 Gasket Replacement of Radiators and
radiators butterfly valve.
To Make radiators and valve section free
from leakage.
4 Replacement of nut bolts if required to provide proper fitting.
5 Internal cleaning of radiators with oil flushing inside radiators.

7.  Conservator tank it self indicates it s role in transformer
performance. Conservator tank is simply use for storage of extra transformer
oil that utilized by transformer at the time of heavy loading, what happens
actually at the time of loading hot and cold oil gets circulate in transformer via
radiators for cooling of transformer . at that time cold oil stored in conservator
goes down towards core and winding to make it cool. Silica gel breather is also
connected through conservator for cooling so pollution of air and all dust
partials also stores in conservator, plus due to that dust partials and
transformer oil, inside of conservator tank gets rusted and the whole rust and
dust stores in conservator so internal cleaning and maintenance of it is
necessary. IN SOME CASE DURING OVERHAULING WE FOUND MORE THAN 5KG
OF DUST AND RUSTS IN CONSERVATOR IN 15YEARS OLD TRANSFORMERS.
Sr.No Services Benefit
1 Gasket Replacement of conservator
main cover
To prevent it from oil leakage.
2 Internal & External cleaning of with wire brush to remove dust and rust.
3 Gaskets replacement of valves and
oil topping flange.
To prevent it from oil leakage.
4 Cleaning and gasket replacement oil MOG
5 Replacement of silica gel breather To provider dry air for transformer breathing.
6 Air cell filling if applicable.
7 Oil level glass and gasket set replacement

8. We are provides maintenance services regarding
transformer main tank cover as describe below. Main tank cover
contains pressure expansion vent which is use full to protect the
transformer at the time of un necessary pressure generates
inside transformer due to certain fault. We are also provides all
HT – LT Bushing cleaning with suitable cleaning material.
Sr.No Services
1 Gaskets replacement of main tank cover
2 Gasket and pressure die farm replacement of explosion vent
3 Gaskets replacement of all valves and air realized plug mounted on tank cover.
4 Cleaning of transformer tank cover with cleaning brush.

9. Transformer oil is made up from petroleum distinction. It is mainly carbon
composition, so it contains very good insulation and cooling property. But due to
dissolution of gases, impurities and continues heating cooling cycle its insulation
property gets spoil so its filtration and testing becomes necessary at the interval of
quarter or year.
We are providing oil filtration with dual filter high pressure vacuumed machine. We
are also providing approved oil BDV and DGA test certificates.
Sr.No Services Benefit
1 Oil filtration with high pressure vacuum
filtration machine.
To improve its quality and BDV
value.
2 BDV testing before overhauling To identify oil quality before
filtration
3 BDV testing after overhauling To check quality improvement after
filtration.
4 Oil circulation in transformer via oil filtration
machine
To improve IR and PI value of
Transformer

10. OLTC( Online tap changer) is a addition chamber
of transformer that use for changing output it voltage by
interchanging tap position of winding. OLTC chamber gets
addition oil and oil storage chamber . Due to operation of OLTC
tap changing switch at 11KV sparking and carbon generates on
its tap contact and rotating contacts. The generation and lagging
of heavy carbon spoils oil quality and ultimate transformer life
careless regarding oltc maintenance is a enough reason for
transformer failure.
Sr.No Services Benefit
1 Oil filtration of OLTC oil To make oil free from impurities and carbon
partials
2 Cleaning and proper thigh ting of OLTC internal contacts
3 OLTC top and bottom inspection window gasket replacements
4 OLTC mechanical and electrical operation testing
5 OLTC to panel wiring checking and maintenance

11. Core and winding is main part of
transformer. we are getting power transfer
and voltage regulation due to correct
design of active part.
paper insulation is used for coil winding. due to heating of oil
carbon particles and surges gets deposited on core and coil
portion. That surge and carbon particles increase the load
loss ( cu loss) of transformer. During overhauling we
removes that impurities via hot oil wash and physical
gentle cleaning of core and winding.
Sr.No Services Benefit
1 Hot oil wash of core and coil To make core and winding free from impurities
and surge that leads to loss reduction.
2 OFTC contacts cleaning , thigh ting and operation checking and smoothing.
3 OLTC switch gaskets
replacements
To make oltc switch free from oil leakage.
4 Physical inspection of
winding joints and tapping
conditions and maintenance
if required.
To avoid transformer failure and improve
transformer life.
5 Thigh ting of core clamps and core tie rods.
6 Gaskets and rubber rings replacement of HV and LV bushings.

12. We are providing quality painting with the help of air gun and
compressor. We are providing a high resistance anti corrosive paint to
improve metal corrosive resistance. We provides one layer of primer
and then after two layer of well known branded paints to make it
better and protected from weather conditions.
We are providing above mention services in transformer overhauling
and remaining
general maintenance work is mention hear: -
Sr.No Services
1 Cleaning and painting of transformer tank and cover
2 Cleaning and painting of conservator tank
3 Internal cleaning of transformer tank
4 Cleaning and painting of OLTC (if applicable)
5 Cleaning and painting of radiators.
6 Nut , bolt and washer replacement at every joints where required.
7 Shifting of transformer during overhauling if required.