Asset Management Strategy for Distribution Transformers in Indian Power Utilities

Distribution Transformer (DT) is the heart of a power distribution system. The DTs, especially of ratings 25 kVA to 250 kVA, are large in number in Indian power distribution utilities and most of these are old transformers, with high No load losses and Load losses. They fail frequently predominantly due to ageing, overload, and poor maintenance, causing huge monetary loss to the utilities and power interruptions to the customers. As it is most economical and faster way of restoring power supply to the affected area and customers, the failed DTs are repaired and put into service again, instead of providing a new DT there. Frequent failure and repair has led to the DTs losing their functionality, and maintainability. The DTs are also showing operational issues in terms of huge losses. A study is done in this paper, to find out the effect of replacing all these old Repaired Good DTs (RGDTs) by Amorphous Metal core DTs (AMDTs), on the net saving in system losses. This kind of asset management strategy, which is usually performed for large power transformers, is carried out for DTs in this paper, with thorough analysis and calculation of payback period. The study revealed encouraging results