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Trafotech SEALED BREATHING SYSTEM- the easiest way to get rid of frequent maintenance of Silica-gel
Breathers and keep transformers dry


Series A: For transformers 16 KVA to 400 KVA ///  Series M: For transformers 500 KVA to 500 MVA

Normally, transformers are provided with Silica-gel breathers to protect them from atmospheric moisture. In fact, Silica-gel
breathers, in their best form also, are in-capable to fully protect transformers from moisture. This is called Free-breathing
system, which does not fully protect transformer from outside moisture.
And unfortunately, breathers generally do not remain in their best form due to lack of frequent maintenance they require,
thereby further de-grading their performance as a moisture protector device. This creates a huge revenue loss happening due
to ingress of moisture to transformer solid insulation and oil, reducing their life to half or even lesser. Presence of moisture in
solid insulation accelerates its ageing process and pre-mature end of transformer takes place.

IMPORTANT: Life of liquid insulation is reversible, but life of solid insulation is irreversible. Generally, life of transformer = life of

The pre-mature death of a transformer not only causes loss of equipment but the outage generally creates more production
loss than the cost of transformer.

Many complicated breathing systems have been tried but none succeeded 100%. Some of them failed due to technical
inferiority and others, due to high cost.

Salient features of Sealed Breathing Systems invented by Trafotech

a. Efficiently protect the transformers from moisture & keep transformers dry
Provide 100% isolation level to transformer from atmospheric moisture

b. Economical  in long run
c. No operating cost
d. No maintenance cost

e. Actually extend the life of transformers which were originally designed for operation with conventional Silica-gel

f. All Trafotech transformers are equipped with in-built Sealed Breathing Device.

The system can be installed on any working transformer in the field, without altering the original design of transformer.

Experience shows that life of transformer extends by >10 yrs if it is operated dry i.e. at an overall moisture level of < 0.7% by

Trafotech On-Line Oil Purifier System

There are 2 sources of moisture, External and Internal.

Entry of external moisture is protected by �Sealed Breathing System�.
Moisture generation takes place inside the transformer tank also due to the presence of Hydrogen/ oxygen.

On-line oil purifier extracts the moisture from transformer while transformer is in service and keeps the transformer dry.

The system fulfills the basic requirement of keeping the liquid and solid insulation dry. This basic requirement is not fulfilled by stream-line filter machines due to following reasons:

1. Oil can absorb/ store moisture to a certain level say 200 PPM, after which it releases moisture/ water due to its incapability to store moisture beyond that limit. This moisture finds its way to solid insulation.

2. Solid insulation has capacity to store moisture app. 300 times than oil, so, major moisture lies with solid insulation, not with oil.

MORE MOISTURE IS STORED IN SOLID INSULATION THAN OIL Transformers oil is filtered generally when the transformer is under shut down. Problem starts here!! When the transformer is de-energized, the moisture in oil migrates to solid insulation and vice versa. That means we can extract say 1 part of moisture from oil; Rest say 299 parts are well stored in solid insulation, which again migrates to oil after the transformer is energized and put on load.

4. Streamline filter machines can-not make a wet transformer dry.  The basic requirement, that windings should be hotter than oil to extract moisture from solid insulation, is not fulfilled by filter machines. Conventional Filter machines can filter the oil but can-not dehydrate a transformer. They allow major part of moisture to remain in solid insulation.

So, it is equally important to have dry solid insulation, not only dry liquid insulation. In fact, liquid insulation can-not remain dry, unless solid insulation is dry.

Life of transformer = Life of insulation.

Liquid insulation ageing is reversible. Solid insulation age is non-reversible.

Once the DP value of paper falls, say from 1200 to 200, it can-not be reversed, whereas wet transformer oil can be dried by filter process.
Trafotech On-line oil-purifier over-rules the above deficiencies and keep both the liquid & solid insulation dry and make a wet transformer dry while the transformer is in service.
Benefits of On-line oil purifier system

a. It performs without taking shut-down on transformer.
b. It performs without consuming any electric power.
c. It can bring down moisture level of a wet transformer to below 15 PPM.
d. It can extract moisture from liquid (Oil) and solid insulation both.
e. In addition to moisture, it improves the specific resistance & Acidity value in oil.
f. It is provided with a micro-filter to remove solid impurities and a drain sump for removal of sludge periodically.
g. It is provided with anti-oxidant injection system.
h. It can easily be installed on old transformers of any make operating at site with-in 2 hours without any design  
i. The moisture level in oil (in ppm) can be read on instrument installed on transformer.  

The system requires some space on ground level near the transformer.
No special foundations are required.

The system is connected to existing top and bottom filter valves of transformer.

Some quantity of transformer oil is required to install the system which remains in Client�s scope of supply.

The oil purification system comprises of a micro-filter/ an adsorbent and acidity correction substance / a desiccant/ an anti-oxidant.

The anti-oxidant requires to be added in the transformer every 2 years. This is supplied by us at a nominal cost and can be added by user at site. The cartridges require replacement after 6 years in a normal transformer. The cartridge can be re-activated also. The cost is nominal and replacement can easily be carried-out by site-staff without taking shut-down.