The significance of transformers and its role in power industry needs no introduction. While on duty, transformers not only transmit power, but also ensure safety of the equipment at different voltage levels. The size of the transformers might vary according to their residential and industrial uses, but the importance of transformer maintenance is the same irrespective of its volume.
Transformers are maintained in two perspectives namely transformer preventive maintenance and transformer maintenance based on requirement. Be it oil based transformer or dry type, the staff are trained in transformer maintenance appropriately.
Oil based transformers
In the case of oil transformers, proper installation and operations are ensured. Care is taken not to overlook basic requirements which could grow up to serious damages when let neglected.
The staffs are tutored about probability of trouble shooting certain anticipated conditions, which are grouped together as unscheduled maintenance.
Visual inspections followed by repairs, adjustments and replacements are regular transformer preventive maintenance. The transformer maintenance predicts damages and corrects the faults that lead to such damages so that things do not go out of control.
The temperature, devices, insulation systems, protective coatings of the transformer are brought under observation.
For low insulation resistance, earth fault or absence of primary voltage could be the reason and position or connection should be checked. For spurious triggering during operations, the sensors and thermometers should be studied.
Dry type transformers
Ventilation and atmospheric conditions are important criteria of dry type transformers because any leakage or contact with atmosphere could turn disastrous. Proper ventilation ensures cooling in dry type transformers. Such ventilations are handled depending upon geographical locations where the transformers are installed.
Dry type transformers are usually installed in areas free from dust and chemicals. As a part of transformer preventive maintenance, dry transformers above 75kV are positioned 12 inches from walls and other transformers to ensure uninterrupted flow of air around the apparatus. If located near combustible materials, minimum separations are determined by National Electric Code (NEC).
If significant noise is present in the location, it is considered while installing transformer there. In higher altitudes where air density decreases, the temperature is considered appropriately for transformer maintenance.
The dry transformer could complain low insulation resistance which occurs due to humidity in surface of windings. As transformer maintenance, clean dry air ventilation should be ensured. For unexpected secondary voltage, the position or connection should be altered.
Dry transformer preventive maintenance is classified in two types namely in energized state and de-energized state.
The alarm trips of the transformer must be taken seriously and the reasons should be immediately investigated.
Transformers and ageing
Besides its type of insulation, transformer maintenance is distinct for ageing transformers. Transformers have a life span between 30 to 40 years based on the rate of deterioration. Few exceptional transformers could last only for 20 to 25 years.
Since electric surges are the most popular reasons for transformer breakdowns, the same is prioritized in transformer preventive maintenance.
Conclusion
The art of maintaining transformers according to its insulation is a very comprehensive science and must be fervently followed to extend the life span of the apparatus and the profits thus gained.