By Jean Saayman, Stuart Chambers, Bruce Sunga

The degradation processes are primarily chemical in nature and are accelerated by the presence of promoters, such as acids, oxygen, water, and other contaminants.

During a transformer’s service life, numerous electrical phenomena and other stresses can occur that degrade the physical and dielectric properties of its oil and paper. The degradation processes are primarily chemical in nature and are accelerated by the presence of promoters, such as acids, oxygen, water, and other contaminants. If the degradation processes are left unchecked, it will eventually compromise the integrity of the equipment. Electric utilities should continually monitor and reduce the level of contaminants and oil degradation products in transformers in order to maintain the equipment’s performance, prevent failure, and prolong the equipment life. Studies show that by removing these promoters from the oil, the life of a transformer can be significantly extended.

The benefits of maintaining low moisture concentrations are established knowledge in the electrical industry; however, as a greater understanding of the degradation process has been gained via research and development, the benefits of removing the other contaminants has come to light. Powertech Labs has conducted several laboratory investigations into the formation of these byproducts and the benefits of removing them, and has successfully developed, studied, and implemented novel online purification techniques on operational field transformers. This article provides an overview of the aging process of transformers, the chemistry involved, and which compounds and byproducts further promote aging.

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