Transformer oil recycling and types of transformers

Recycling of transformer oil is lauded not only for its economic benefits but also for environmental advantages besides saving the management from disposal woes. It is also considered as a form of asset management. Onsite recycling of transformers varies based on the type of transformer namely sealed or breathing type.

The contamination depends upon the exposure of the transformer to the atmosphere. Transformer oil filtration removes impurities and improves the quality of the oil and adds to its functional capacities.

Transformer oil contamination

Prolonged operations which comprise energy transfer causes moisture in the oil and oxidation which leads to formation of semisolid hydrocarbon sludge. The dielectric qualities of transformer oil suffer a setback due to oxidation and accumulation of byproducts. In such instances, oil is filtered to avoid deterioration.

Transformer oil is susceptible to contamination through a range of reasons. The quality of transformer oil is damaged due to high acid content, dissolved gasses, sunlight, solid particles and increased temperature which hamper the insulating capacity of the oil.

Hering VPT confronts oil deterioration with its transformer oil purification product line and transformer oil regeneration systems. EOK TORS oil regeneration product line has been client’s delight in restoring transformer’s insulating liquid back to its optimum condition.

Consequences of used transformer oil disposal

Replacing used oil with new oil is not advised since disposal of contaminated oil poses a threat to various forms of lives including humans. Besides, recycling of transformer oil saves money spent on maintenance and translates to profits.

Hermatically sealed transformers

Since transformer oil does not come in contact with the external atmosphere in sealed transformers, oil deterioration is rare and these transformers are mostly maintenance free. Owing to the sealed nature, the oil is devoid of sludge and oxidation.

Transformer oil filtration is executed by vacuum type dehydration and centrifugal type which removes moisture and solid particles from the transformer oil. Sludge in sealed transformers are removed by employing filter candles which may be edge or centre.

On the other hand, coarse materials in the transformer oil are filtered through cartridges of different dust holding capacities from 500 microns to 0.5 micron size. Preliminary filters remove particles above 1 mm size which are also magnetic in nature.

Vacuum method is employed to remove impurities. The oil is heated to separate moisture and gasses from one another. Filtration is facilitated when the viscosity of the oil decreases. Gases are removed through dehydration and degassification chambers.

Breather transformers

Oil deterioration in free breathing transformers is faster than sealed transformers. Breather transformer inhales air with moisture, when exposed to heat.

Open transformers are more susceptible to oxidative transformer oil deterioration than sealed transformers do. Due to such exposure to atmospheric oxygen, water carries oxygen and leaky gaskets add to the danger by promoting oxidation and moisture contamination. Such oxidation also results in sludge formation.

The damage to the insulation parts is averted by silica gel which absorbs moisture. Silica gel is used in breather transformers to prevent moisture from entering into the apparatus. High vacuum insulating transformer oil regeneration system with an ample silica gel regeneration tank is employed for this purpose.

After three to five passes in the transformer oil filtration machine, the oil regains its original characteristics and is as good as new.

Hering VPT has more than a century old expertise in providing transformer purification and oil treatment solutions which are backed by an impeccable German precision. They also assist clients by providing training in transformer maintenance. Hering products are designed to maximize plant’s uptime, minimize maintenance, avert repairs and to enhance success in their client’s operations.