We cannot imagine our life without electricity. It is an important part of our daily life. We use many electrical appliances in our daily life, but these appliances have no values if there is no electric current available inside.

Electric current is available in the open source, but we cannot use the direct current from the open source. Transformer can produce electric current by converting the direct current (DC) into alternating current (AC) through electromagnetic induction.

Transformer makes our life very easy, but transformer can’t work without insulating oil. Insulating oil/Transformer oil makes the transformer insulate perfectly. So testing and analysis of transformer oil is very important for the transformer.

Transformer oil:

Transformer oil is used to insulate the electrical power transformer, and it is also used for the cooling purpose. It is used to stop the direct contact of oxidation reaction in the transformer.

It is two types: 1) Paraffin- based transformer oil

2) Naphtha-based transformer oil

Analysis and Testing of Transformer oil in different types. There are different types of methods for testing of transformer oil.

1) Acidity test of transformer oil:

We can test the acidity nature of transformer oil in the process of titration.

When a particular quantity of alkali is mixed with the same quantity of oil its nature will be changed into alkaline or acidic or in neutral with according to the acid present in the oil. If the added alkali in the solution is same to the required quantity of alkali for balance/neutralize the acid present in transformer oil then the pH value of oil will be 7. If the added alkali in solution is more than the required quantity of alkali for neutralizing the acid present in transformer oil then the pH value of the oil is 7 to 14, and the oil will be alkaline. And if the added alkali in the solution is less than the required quantity of alkali for neutralizing the acid present in transformer oil then the pH value of the oil is 0 to 6, and the oil will be acidic.

2) Sludge test of Transformer oil:

It is the mixture of different types of petroleum hydrocarbon, heavy metals, water, and solid particles. It composed of alkenes, aromatics, resin, and asphaltenes. Sludge formation in transformer oil is due to oxidation of transformer oil.

3) Flashpoint test of Transformer oil:

Flashpoint test is the test of breakdown voltage in the transformer oil. In a particular point of minimum temperature when the transformer oil becomes vapor is called flashpoint and the value of flashpoint in transformer oil is 140- degree Celsius.

Transformer oil composition:

Mainly the Transformer oil contains with mineral oils. We also called the transformer oil as hydrocarbon mineral oil. Aromatics, Paraffins, Naphthenes, and Olefins are the organic compounds of Transformer oil. Aromatic is used for the proportional balance between aromatic and aliphatic hydrocarbons present in the transformer oil.

Analysis of PCB in Transformer oil ! Testing and Sampling:

PCB stands for polychlorinated biphenyls. It is banned for many years for the new transformer. It is legally allowed for the power plants and industries. Chromatography gas is used to detect and captures the electron to measure the concentration of PCB in transformer oil.

Transformation oil filtration and dehydration:

Dehydration is the process, to remove the moisture from a body or any substance. It is used in the transformation oil because of to improve the efficiency of the transformer and remove the sludge and moisture from the oil.

Filtration is used in transformation oil because to filtrate the oil in high vacuum filtration machine. It helps to extract the impurity from the oil. Dehydration and Filtration both are used for extract the sludge, impurities, moistures, acidity from the oil.

Dissolved Gas Analysis (DGA) for Transformer:

The study of dissolved gasses in the transformer is called as Dissolved Gas Analysis (DGA). Sometimes the transformation generates some gases, to detect the unknown gases and fault from the transformer we need the help of DGA (Dissolved Gas Analysis).

Furan analysis and testing of transformer oil:

The compound of carbon and hydrogen is called Furan. It indicates the abnormal stress, overheats, short duration, in a transformer. If the count of furan is 2500 ppb above it indicates that the transformer is about to fail.

Breakdown voltage (BDV) of Transformation oil:

BDV stands for breakdown voltage. When the transformer operates initially, the oil became very dirty for which the transformation can’t function properly. BDV check the quality of the oil. The BDV test repeated the duration of 6 months. It is the important testing of Transformation oil.

Water Content in Transformer oil:

The amount of water or moisture is very low in the transformation oil. The water can affect the breakdown strength of the insulation and the temperature of the insulation. In the transformer oil, the water is available in 4 forms: free water, emulsified water, dissolved water and in chemically bound water.


All the above testing and analysis of transformer oil are only for to observe the oil and extract the impurities, sludge, acid, moisture, dissolved gasses from the transformer oil. These tests can give the information of contaminants, which are included in transformer oil and protect the transformer from damage.