All You Need to Know About Transformer Oil Filtration

All You Need to Know About Transformer Oil Filtration

Transformers play an important role in the electrical power industry. Transformers convert power to appropriate levels for other system components to be safely used. Transformers need to be maintained to guarantee long life. A good quality and clean oil is important as it supplies efficient performance for the transformer. 

If the transformer oil is exposed to undesirable materials like acids, metal dust, moisture, it will degrade over time. If you find out that your transformer oils contain dissolved gases, dust, and other contaminants, it is time to take action for the oil to be filtered and purified. Transformer maintenance and services centres offer high-quality equipment for treating oil using in line transformer oil filtration techniques. These techniques can help sustain an excellent performance, safety and ease of operation for transformer maintenance staff.

To learn more about transformer oil filtration, here are the things that you need to know.


The Many Functions of Transformer Oil

Transformer/insulating oil is often stable at high temperatures. Other than that, the following are functions of insulating oil:

  • As a Cooler
    • When voltage goes up/down, the temperature of the transformer’s windings increases, oil is used to cool down the condition.


  • As an Insulator
    • It acts as an insulator between the windings. It increases the resistance between them and avoids short circuit.


  • For Security
    • It operates the level of oil inside the transformer. The temperature display of oil describes the inner condition of the transformer and shows any short circuit status. In this way, you will prevent the transformer from being severe losses and damages.


Types of Insulating oil

There are two types of insulating oil when you are dealing with transformer oil, which are: 

  1. Paraffin-based Insulating Oil: This type of insulating oil is derived from special crudes that contain substantial amounts of n-paraffin. This type of insulating oil is less oxidised than naphtha based.
  2. Naphtha-based Insulating Oil: This type of insulating oil is derived from special crudes that contain a low amount of n-paraffin.


While you are using insulating oil, the oil may be exposed to materials which can affect its quality. The insulating oil fails to function because of factors like excessive high temperature, oxidation and many more. 

However, the oil darkens in colour and the acid in it starts to increase. Oil impurities are one of the main causes of transformers deterioration. To prevent your transformer from failing, your insulating oil should be free from any contamination, dirt and moisture. Thus, transformer oil filtration process is needed.

In this procedure, insulating oil is tested and treated so that transformers will function more efficiently.


The Process of Filtrating Insulating Oil

  • Rising oil temperature

First procedure is to raise oil temperature up to over 65°C to give latent heat that separates moisture and gases. Heating the oil will make it easier to filter because of the decrease in oil viscosity.


  • Removal of dirt and impurities

Second procedure of filtering transformer oil is to remove the sludge and dirt from the insulating oil. There are two methods to eliminate dirt in the transformer oil.


1. By using Filter Candles

  • Insulating oil filtration by filter candles can be classified by using classical edge filter or depth type filter. 
  • However, new advancements were made in which transformer oil filtration machines use filter cartridges rather than edge type paper filters.


2. By using Centrifuging Action

    • Another way to separating dirt from oil is through centrifugation. 
    • With this process, you can save recurring cost of changing filters.
    • Dehydration and degasification of insulating oil


This is the final stage of dehumidification of insulating oil and removal of gasses. This process is often completed in the degassing chamber.

In conclusion, it is important to maintain your transformer oil so that your transformers can function more effectively. It does not just help extend your equipment’s life span, but this also improves its efficiency. Maintaining your transformer oil can help your equipment in the long run.