Transoil Services

Why Transformer Oil Regeneration and Purification? 

As transformer oil ages, it oxidizes and begins to break down. The by-products of the degradation process include acids, aldehydes, and peroxides, which bind together to form sludge. Sludge attacks the cellulose insulation, inhibits oil flow, and traps heat inside the transformer. Eventually the dielectric gap is bridged, resulting in failure of the transformer. It is therefore essential and vital that transformers are taken care of in the best possible way, because a transformer that has failed not only causes loss of revenue for the power authority but can at times be a very dangerous affair resulting in plant damage and loss of life.

Transoil’s mobile regeneration system restores transformer oil by removing acidity, sludge and soluble oil decay products with Fuller’s Earth treatment technology. When the treatment is complete, the reclaimed oil meets or exceeds international standards for new oil with lower acidity and improved tan delta, interfacial tension, and oxidation stability. The cellulose insulation and internal components of the transformer also benefit from the flushing effect of multiple passes of hot reclaimed oil, which helps remove decay products and sludge from surfaces.

Regular regeneration treatments every 4 to 9 years for each transformer in any network offers significant benefits, such as reduced risk of unplanned outage and costly downtime, reduced maintenance costs and extended equipment life.

In addition, the regular purification of electrical insulating fluids is necessary to ensure longevity of a transformer, because moisture, solids and gaseous contamination can seriously affect the function of electrical insulating fluids as a coolant and insulator. It’s in this context that Transoil offers a uniquely designed three stage process of oil treatment focused on using the latest technology to suit any needs.

The spreading of oil, which is part of the process, is vital for easy release of moisture and gaseous containments. It is accomplished by a porous media cartridge called a coalescer. In this process heated or unheated oil passes through the layer of bonded fiberglass, where millions of sharp edges shear oil and expose it to the effect of the vacuum. Spreading of oil by passing through a coalescer is so effective that oil can be treated at temperatures as low as 20ºC. This method ensures that oil dryness to 3ppm and lower can be achieved without exposing the oil to high temperatures. The release of combustible gas from the oil is also highly efficient ensuring that the oil is fully degassed in the electrical apparatus.

The advantages of using Transoil’s purification and regeneration machine includes, among others, it is a highly cost effective alternative to new oil, the extension of a transformers’ useful life is guaranteed, it is environmentally friendly, and best of all the plant can be used on live or energised transformers, illuminating unnecessary transformer downtime.

Difference between Oil Purification and Regeneration

Oil purification forms an important part of regular, preventative transformer maintenance. In the process of purification, water, dirt and gasses are removed from transformer oil. The oil leaving the plant will have improved dielectric strength.

When the oil in a transformer reaches a stage (due to aging process) where purification/degassing is no longer efficient, the oil must be changed or regenerated.  

Regeneration is the complete treatment of oil and uses Fuller’s Earth to get the oil to a like new condition. The oil leaving the plant will have improved oxidation stability, colour, and reduced gassing tendency.

Regenerating Oil versus Replacing Oil

The norm for many Power Utilities has been to simply replace the Transformer Oil once it has reached the end of its useful life. Besides being an expensive option it is not environmentally friendly and is not in the best interests of the transformers wellbeing:

New Oil:

• There is a limited supply of Virgin Transformer Oil available and the price is sensitive to this fact. The latest quoted price for oil is approximately US$ 2,15 per liter.
• Flushing Down a dirty transformer reaches only 10 – 15% of the interior surface.
• Changing Oil does not remove the deposited sludge on the core and coils, therefore it is not a solution to the problem, as this sludge mixes with the new oil.
• Disposal of the ‘changed out’ oil is now also a problem.
• A small amount of badly oxidised oil can ruin very large quantities of new oil.
• The disposal of old oil is potentially an environmental risk with spillage and PCB contamination a common occurrence.

Regenerated Oil:

• Transoils plant can operate on an Energised Transformer, therefore there is no power supply interruption and no loss of revenue.
• No environmental hazard due to oil spillage or PCB contamination.
• No exposure of the core to the atmosphere.
• Not dependant on climatic conditions.
• Complete flushing of transformer and core achieved.
• The cost to Regenerate oil is far less than replacing the oil.
• Oil Regeneration extends the transformers life.