subject: Acceptance Testing and Maintenance of Power Transformer [print this page] Acceptance Testing and Maintenance of Power Transformer
Power Transformer Maintenance
A power transformer is a fairly reliable piece of electrical distribution equipment. With no moving parts, transformers requires minimal maintenance, and are capable of withstanding overloads, surges, faults, and in some cases even superficial physical damage. While transformers can withstand a lot of electrical fluctuations, they do deteriorate with age, and thus need constant monitoring to detect and correct problems before they escalate into expensive repairs. This is where a good inspection, testing and maintenance program comes in.
Heat and moisture related contamination are the two greatest enemies of a transformer's operation. Heat breaks down transformer insulation and accelerates chemical reactions that take place when the oil is contaminated. One of the ways to address the heat problem in a transformer is to ensure the transformer is properly cooled, through regular cleaning of the cooling surface, maximizing ventilation, and monitoring load to ensure the transformer is not producing excess heat.
Contamination is detrimental to the transformer, both inside and out. Dirt and grease deposits severely limit the cooling abilities of radiators and tank surfaces.
The oil in the transformer should be kept as pure as possible. Dirt and moisture will start chemical reactions in the oil that lower both its electrical strength and its cooling capacity. Contamination should be the primary concern any time the transformer is opened. Most transformer oil is contaminated to some degree before it leaves the refinery. It is important to determine how contaminated the oil is and how fast it is degenerating. Determining the degree of contamination is accomplished by sampling and analyzing the oil on a regular basis.
Although maintenance and work practices are designed to extend the transformer's life, it is inevitable that the transformer will eventually deteriorate to the point that it fails or must be replaced. Transformer testing allows this aging process to be quantified and tracked, to help predict replacement intervals and avoid sudden failure.
