Degasification: Degasification removes harmful gasses and water from the oil. This is an essential aspect of transformer maintenance since water decreases the dielectric strength of the oil and dissolved gasses cause arcing and corrosion leading to overheated connections.
The amount of water held in suspension changes in relation to the temperature of the oil.
Degasification is routinely performed in conjunction with all other oil reclamation services.
Dielectric Strength: Dielectric Strength is a measure of the electrical strength of a material as an insulator. Dielectric strength is defined as the maximum voltage required to produce a dielectric breakdown through the material and is expressed as Volts per unit thickness. The higher the dielectric strength of a material the better its quality as an insulator.
Dissipation Factor: This test measures the dielectric losses in insulating oils due to heat dissipation in an electric field. High values indicate the presence of contaminants, oxidation products and metal particles.
Fuller's Earth systems: Reclamation of oil with a high acid content requires fullers earth filtration and degasification. Fullers earth removes both acid and particulates from the oil including sludge and other contaminants. Sludging is a direct result of high acid content and over time sludge can harden over internal parts of the transformer preventing the oil from circulating properly.
If reclamation is done in the early stages of acid build-up before sludging occurs, the oil will retain its properties longer under normal operating conditions.
Hot Oil Dry Out: Once the used oil is removed from the transformer, the core and coil assembly are rinsed with clean oil to remove sludge or sediment caused by oxidation.
The transformer is then partially filled with hot oil which is circulated to remove water and contaminants from the insulation. By cleaning the transformer in this manner, the cause of the oil contamination is addressed. Following this, the replacement oil will retain its properties longer under normal operating conditions.
Inhibitor: A number of organic chemical compounds are known to slow down the oxidation when added to lubricating or insulating oils. Such additives are known as antioxidants or oxidation inhibitors. Unfortunately, all known oxidation inhibitors become depleted with time. When all of the inhibitor has been used up, the oil starts to deteriorate again, and deterioration proceeds in the same way at the same (or greater) rate as in the uninhibited oil. The useful life of the oil is extended by the amount of time the inhibitor remains effective, before it becomes depleted.
PCB: Polychlorinated biphenyls (PCBs) are very toxic and persistent in the environment. PCBs are widely used in electrical equipment, including transformers. Many transformers still contain traces of PCB-contaminated oil even after the oil has been changed several times.
The proposed PCB Regulations from the Canadian Environmental Protection Act states that transformers must have a PCB count less than 50 ppm to be operational. It is expected that the proposed deadlines for ending the use and storage of PCBs will result in the removal, by 2009.
Ppm: Parts per million
Retro filling: involves removing the used oil from the transformer and replacing it with reclaimed oil.
TAN: Total Acid Number
Vacuum Filling: Vacuum filling is a critical step in ensuring that the new quality oil does not become contaminated during retro filling of the transformer.
Water Content: A method that extracts water from an oil sample and determines the amount of water. Excessive water in the oil destroys the lubricant's ability to separate moving parts, allowing severe wear to occur. In addition water affects corrosion rates, oil degradation resulting in loss of lubrication and premature plugging of filters, minimizing the effect of additives, and supporting the growth of bacteria.
