Transformers

Transformer successful operation depends on correct installation, loading, and maintenance. Also it depends on proper design and manufacture. As is with all electrical devices, neglecting of certain requirements may lead to severe problems, if not to the equipment loss.

This approach consists of completing preventive, predictive and corrective maintenance. The preventive maintenance involves schedule maintenance and regular testing. Predictive maintenance involves extra monitoring and testing, whereas corrective maintenance considers repairing and restoring transformer integrity to its original condition when degraded conditions are found. The goal of the transformer protective maintenance is to control and prevent serious oil and winding insulation deterioration. Mineral oil and winding paper insulation are impacted by moisture, oxygen, heat, and other agents such as copper, iron, electric stress, etc. The end result is that oxidation happens in the oil which leads to transformer sludging. In sealed units ingress of moisture via atmosphere or seal leaks needs to be stopped. Moisture will decrease the dielectric strength of both the oil and the winding insulation systems. Also, transformer extra heating will cause the winding insulation (paper) to decompose which in-turn creates moisture. Increased moisture created in the paper not only decreases the paper insulating strength but also, as temperature increases, the moisture will migrate from the paper insulation to the oil and decrease its dielectric strength. The most important step is to construct transformers so that moisture and oxygen are kept out. The next step is to operate transformers so that they are not operated beyond their temperature ratings and limits. Also, the severity of deterioration needs to be controlled by periodically monitoring and testing transformer insulation, and take mitigation measures to restore transformer to its origina.