A power transformer is most costly and essential equipment of an electrical transformer.So for getting high performance and long functional life of the transformer, it is desired to perform various maintenance activities. Not only that, a power transformer also requires various maintenance actions including measurement and testing of different parameters of the transformer. There are mainly two types of maintenance of transformer. We perform one group is in routine basis, and second group is as when required. That means for getting smooth performance from a transformer we have to perform some maintenance actions in regular basis.

Some other type of maintenance of transformer we perform as when they are required. But if one performs regular maintenance properly, he may not have any provision of performing emergency maintenance. The regular checking and maintenance of transformer is also known as condition maintenance. Hence by proper condition maintenance one can avoid emergency and breakdown maintenance.

That is why one technical personnel should mainly concentrate on condition maintenance. As 100% condition maintenance causes 0% breakdown of an equipment. There are many different maintenance action, to be performed on a power transformer. Some of them in yearly basis, some of them are monthly basis, some other are quarterly, some are half-yearly basis. These are mainly transformer maintenance action, which to be performed in 3 to 4 years interval.

Monthly Basis Maintenance of Transformer
Let us first discuss about the action to be taken on power transformer in monthly basis.

1. The oil level in oil cap under silica gel breather must be checked in one month interval. If it is found the transformer oil inside the cup comes below the specified level, oil to be top up as per specified level.
2. Breathing holes in silica gel breather should also be checked monthly and properly cleaned if required, for proper breathing action.
3. If the transformer has oil filled bushing the oil level of transformer oil inside the bushing must be vidually checked in the oil gage attached to those bushing. This action also to be done monthly basis.

If it is required, the oil to be filled in the bushing upto correct level. Oil filling to be done under shutdown condition.