Transformer Oil Recovery DRYCORE Solutions
Transformer oil recovery at the transformer’s operational site is an important element of preventive transformer maintenance. Insulating oil provides almost 80% of the electrical strength inside a transformer. Transformer oil performs several functions, including cooling and insulating current-carrying elements, and is an essential part of transformer insulation. The quality of the oil directly affects the reliability and operational lifespan of power transformers.
The Role of Transformer Oil in Transformer Reliability
Transformer oil, serving not only as a cooling medium but also as electrical insulation. Over time, oil loses its insulating and physical properties due to oxidation and contamination by water, gases, and solid particles. In such cases, specialists face the task of cleaning and regenerating the oil to restore its original characteristics and extend the transformer’s service life.
Aging or deterioration of insulating oil is usually associated with oxidation. When oxygen and water appear in the oil, oxidation occurs even under ideal conditions. Contaminants from transformer solids that dissolve in oil also affect its condition. Reactions between unstable hydrocarbons, oxygen, moisture, and heat accelerate oil breakdown. Acids formed during oxidation attack cellulose and metals, forming sludge, metal soaps, aldehydes, and alcohols. These settle on insulation, tank walls, breathers, and cooling systems. Sludge appears faster in heavily loaded or overheated transformers, increasing oil viscosity and reducing cooling efficiency.
Transformer Oil Recovery in DC-R units
In cases of critical oil degradation, after mechanical and vacuum treatment, the transformer oil recovery process in DC-R equipment begins. Regeneration removes dissolved oxidation products and restores the oil’s antioxidant protection. One of the most effective methods uses adsorbents capable of absorbing oxidized compounds and acids, thereby restoring the chemical properties of the oil.
During transformer oil recovery, the adsorbent is automatically reactivated after each cycle or when fully saturated at any point during the process. This allows repeated use without replacing or disposing of the adsorbent after every cycle. Regeneration occurs continuously without shutdowns for maintenance, saving time and costs while protecting the environment from waste.
Preventing Solid Insulation Degradation
During aging, transformer insulating oil oxidizes and begins to break down, producing by-products, sludge, acids, and other contaminants that accumulate in cellulose insulation. In other words, the oil becomes aggressive toward the insulation paper, initiating its degradation, which can eventually lead to catastrophic transformer failures.
The regeneration process removes both sludge and by-products formed in the oil and cellulose insulation, stopping the degradation of paper. This process should be carried out before the oil’s acid number exceeds 0.08. Fully regenerated transformer oil can be made almost like new, and with proper maintenance, its service life can be extended indefinitely. Considering the high cost of new oil, regenerating heavily oxidized oil is a practical and cost-effective solution.
Transformer Oil Recovery using DC-R equipment is a complete solution for restoring oil on-site, ensuring reliable transformer operation. Properly regenerated transformer oil protects insulation, improves cooling efficiency, and provides long-term operational reliability.