Some assumption of key gases in the transformer (DGA)

These are some assumption of key gases in the transformer.

Assumption #1:

An arc is produced in the working transformer caused by the Acetylene, So it is easy to diagnose the condition of arcing solely by the help of the acetylene.

Analysis:

The practitioner does not investigate and understand the nature of the arc by the help of this assumption. The question that is it a not dangerous condition of sparking partial discharge in the transferor oil from the grounded part?  There is not a first class of very high dangerous to discharge energy? The high temperature in the transformer produced acetylene and the acetylene make a fault in the transformer oil or rather then produced an electrical arc? It is dam possible that it is the result of mixing or leakage the oil in transformer between the main tank and the LTC tank? All these question are not answered at easily but take the ratios of acetylene to the other gasses into the account. The in accurate result of findings does not mean there is a less dangerous or permission to a high problem to worsen. Due to lake of correct result the situation become over treated like de energizing, draining, incepting the tank and found no prove the reason is partial discharge cannot be seen with bear human eye. 

Assumption # 2:

Transformer show alert as overheated cellulose because carbon monoxide is present in it So it is very easy and reliable to investigate the cellulose problems solely by looking the carbon mono oxide.

Analysis:

  

According to the IEC data of incepted case in service .During the formation of carbon monoxide using the identifier paper involvement in a problem. A inaccurate result will be provided in about 65% of case.

The amount of carbon mono oxide increase it does not mean that any fault involving paper. The fault predicting depend very strongly on the presence of carbon di oxide amount. But actually the increasing amount of carbonmono oxide are directly related to the oxidation of oil it is seeing a large number cases and at the end the result shown increases the heating effect. Now a day all the transformer is equipped with the air preservation system because a small amount of oxygen is always present in the transformer due to leaks in these systems.

Carbon mono oxide by itself not a trustable and safe indicator. It damage the localized insulation paper and these are the following reason behind,

·         The amount is commonly reduced by dilution in a large amount of oil.

·         The level is affected by oil temperature absorption and desorption by paper insulation caused by load.

·         Its ability to move out in the transformer depend upon the oil expansion system type  and the bounding of transformer how tightly is sealed.

Assumption # 3

Hydrogen gas  predict the faults and the partial discharge so it is very sinificient to measure the hydrogen.

Analyze:

Hydrogen is also a key gas and it is present in all problems. So it not to use as a diagnostic gas but it is a predictor. It should be gather with other gases to find the problems with them as a ratio based analysis.in the key gas method three other gases are also include. The methane gas gives batter response when it is combine with hydrogen as a as diagnose and It happened when gases ratios are used. The reason behind is hydrogen gas soluble minimum amount oil. It has also high diffusion ability. (Serveron Corporation)

Conclusion:

In summary the indicator used in the transformer to predict the potential problems in the transformer should not be limited its totally depends upon the concentrations of the dissolved key gases. Identified the problems by trending the gas dissolved levels because we take some step before the tragic failure of the transformer. If the results of key gases concentration is different than we should take another sample to check the correctness of the result. If it clear that the concentration level is increase then use the well knows method to find the problems in the transformer and try to solve the problem.

Dissolved Gas Analysis organization work very hard for batter diagnostic instruments and their progress in this field. DGA expert always gets latest news and takes benefit. Mostly instruments are very good to perform than others. It is very reliable and comfortable to analyses the condition of the transformer. It is very strong program to analyses in laboratory as well as online dissolved gas analysis approaches.

We also analyze that the gasses generated in the transformer occupy with the beta fluid. They have same rule to analyze these gases and the conventional transformer oil and from the test its shows that the amount of gases that produced in the beta fluid due to different types of faults are same for those gases that is produced in the transformer convention oil. Another similarities is solubilizes of gases in the transformer is approximately 10 percent and the same amount of soluble in the beta fluid. 

These graphs dhow the percentage faults at different level.