Some of the issues pertaining to power transformers in Indian power sector

The development of regional grids, inter regional synchronous ties leading to formation of national & international grids and operation of multiple agencies (State Utilities, Central Utilities, and Private players) in a deregulated energy market has created a complex environment in the Indian Power system. High availability & reliable operation assume tremendous importance in such a scenario. The major assets of a power system play an important role in availability and reliability of the system. The transformer is one of the most important and expensive assets in a power system. It forms an important link between load and source of power. Emphasis needs to be laid on the improved design, quality control during manufacturing, maintenance & safety during operation of such vital/critical equipment. The management of such vital assets, when they are in service/operation as well as when they have outlived their expected life/at the end-of-life, is a challenging task for all utilities in a reformed power sector. Residual Life of vital assets and cost associated with Energy Not Served (ENS) due to outages should be major consideration while taking decisions on “Run-Refurbish-Replace”, investment and future planning of the entire power system.

In this paper, overview of some of the critical issues like manufacturing facility/capacity available in the country, requirement and availability of Cold Rolled Grain Oriented (CRGO) Steel & specification requirement, short circuit testing & facilities available in the country, on-site repair & testing, indigenous development of Ultra High Voltage (UHV) class transformer, risk of running and management of old & aged transformers, requirement of On Load/Off Load Tap Changer and Tertiary winding, impact of Geo-magnetically Induced Current (GIC) and DC current due to HVDC system on transformers etc. has been addressed along with action taken so far in that direction with the objective of discussing, and exploring the possibility of improving the situation.