An electrical transformer is only as reliable as its component parts. This fully applies to transformer oil, which functions as an insulator and a cooling medium. Transformer oil is under constant stress from high strength electric field and high temperatures; maintaining the quality of the oil becomes more and more difficult with time. With time, the oil ages and loses important performance qualities.

Oil recovery makes it possible to restore quality to standards and to use the product again. Without a doubt, the process is worth it. Unlike regular oil change, recovery has the following advantages:

• reduction of oil products use and the costs of oil purchases;
• reduction of waste oil disposal costs;
• improvement of oil-filled equipment reliability;
• improvement of environmental situation.

How are transformer oils recovered?

The terms “purification” and “recovery” are often misused and confused. Purification is a part of a full oil recovery process, and by no means is a replacement. Insulation oil is purified to remove particulate matter, water and gas by settling, centrifuging and separation, filtration, heat and vacuum treatment. These methods, however, are not sufficient to remove acidic compounds and other products of aging. Since acidity of the oil has a direct impact on the performance and reliability of the entire insulation system in the transformer, extra treatment is a must. The oil is recovered by adsorbents (bleaching clay, zeolite, silica gel etc). Besides, the oil must be enhanced with additives to stabilize its qualities and reduce oxidation.

Oil recovery using GlobeCore CMM-R unit

GlobeCore has developed a unique CMM-R unit for the recovery of transformer oil. The equipment consists of several sections, each with an important task to completely restore the oil’s performance (degassing section, recovery section, sorbent reactivation and additive injection sections). Fuller’s earth sorbent is used in these units. This sorbent can be restored multiple times and used for many oil recovery cycles. Another important capability of the CMM-R is treatment of oil inside the transformer, either online or offline.