Report on Active Repair for Performance Improvement of Old Distribution Transformer for TANGEDCO
- About the Research Concept
Transformers play a crucial role in the power distribution network. After overhead distribution lines, transformers are the second largest loss-making equipment in electricity networks. Distribution Transformer (DT) is one of the critical and high value CAPEX assets for DISCOMs. For overall DISCOM viability, it is important that each DT must turn into a profit centre. It is estimated that out of 20%1 national average AT&C losses, at least 3-4%2comes from Technical losses in DTs, and it can be brought down to 0.5% and below. Earlier RAPDRP program envisaged feeder energy audits however, there was no separate loss estimation for DT alone. Unfortunately, DT technical losses are not generally measured unless it breaks down and only broken-down DTs are sent for repair. There is minimum to none pro-active asset management approach to DT, it’s repair and O&M.
DT failure rate is one of the important Key Performance Indicator (KPI) for Indian DISCOMs. The losses associated with DT failure are relatively higher in the Indian context compared to the global benchmark. In India, 12-15%3 DTs fail every year and average rate of failure of aluminium wound DTs is more than copper wound DTs. Overloading is cited as one of the root causes of DT failure besides various other reasons. DTs are frequently overloaded during seasons than their actual capacity resulting in deterioration of their operating health and eventually its lifespan. Any failure of the DT before the expiration of its designed lifespan (25 years by CEA guideline4) results in an unplanned outage, production loss, unavailability of critical services and in most cases substantial financial losses to both utilities and customers. Overall, it affects the reliability of the network.
Considering the current financial state of DISCOMs, performance improvement in DT becomes a crucial factor in protecting DISCOMs from further losses. Currently, due to lack of funds to procure new DTs, utility operates the DTs beyond their useful life by inefficiently repairing it several times, resulting in lower efficiency of operation. All these result in reduced efficacy of DTs and high technical losses in the distribution system. Therefore, DISCOMs need to utilize their existing old DTs cost-effectively to get the best out of it. There is a need to save the DISCOMs from the financial burden of investing in the procurement of new DTs to meet the currently growing energy demand.