Transformer preventive maintenance- an activity that rewards
The importance of power in our routine life and the hazards of power failure would well explain the importance of transformer preventive maintenance. Transformer maintenance is considered as profit, since it not only cuts the repair costs, but also adds to the efficiency and the produce.
Monitoring different aspects of the transformer in appropriate intervals comprise transformer preventive maintenance, whose benefits are abundant. Different aspects of transformer preventive maintenance is conducted daily, monthly, quarterly, half yearly and annual basis.
Oil based transformers
Transformer oil purification and transformer oil filtration are included in transformer preventive maintenance steps and enhance operations. When the transformer oil acts as an effectual coolant, it ensures the apparatus to with stand stress that occurs due to heavy loading and short circuit.
Oil being the popular insulating fluid is scrutinized for presence bi products such as sludge and acid formation, so that the flow is not interrupted. Such bi products result in breakdown, whose consequences are heavy to bear. Transformer oil must be monitored twice a year for impurities, flash point, DDA and resitivity.
The electric, chemical and physical attributes of oil are probed to ensure transformer maintenance. The dielectric dissipation attributes contribute to the resistance of transformer in higher temperatures. Monitoring the transformer oil in this regards, saves huge expenses.
The moisture content of the transformer oil is included in its chemical characteristics. When cellulose paper insulation absorbs this moisture, insulating properties receive a beating which results in damage of the equipment.
When oxygen in the atmosphere comes in contact with the oil, it results in acid formation which results in ageing and transformer failure. In another probability, where tension occurs between water surface and oil, the flash point and pour point are affected making the fluid inflammable and affecting its viscosity.
The BDV or breakdown voltage throws light on the presence of contaminants in the transformer, if any.
Checklist for oil transformers
Checking oil levels in the main tank and conservator tank, replacing silica gel when colour becomes pink and detecting leakage and sealing them are three main steps which are a part of transformer preventive maintenance. The oil level in silica gel breather is checked once monthly so that proper breathing is ensured. Besides checking the working condition of oil, training concerned staff is a part of transformer preventive maintenance.
Checklist for dry type transformers
Transformer preventive maintenance for dry type transformers are performed mostly after the equipment is de-energized.
Visual inspection is an important part of transformer preventive maintenance in dry transformers. The screens and coils are scanned for dust and such dust is vacuumed out. The apparatus should be scanned for dust presence once quarterly or half yearly.
While chemical cleaners are avoided, vacuum or compressed air is used without direct contact with components. Rust and decolouration are clues for damage in dry type transformers.
Conclusion
On a concluding note, routine activities such as regular inspection, adjusting spare parts and following instructions religiously contribute to transformer maintenance. When such activities are properly executed, the equipment is more efficient with mitigated expenses.

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