Possible Effects of Smart Grid Functions on LTC Transformers

This paper focuses on load-tap-changer transformer duties associated with Smart Grid (SG) integrated volt/var/kilowatt management functions. The implementation of SG technology, with resultant changes in power systems, may cause increased or excessive tap-changer duties. These duties will be affected by the following: 1) the integration of renewable energy sources; 2) more precise operational voltage control levels for conservation voltage control; and 3) the flexibility, using SG data and communication capabilities, to rapidly change distribution system configurations for maximum SG benefits. If the present distribution systems with radial operations evolve into multiple source systems and feeders, more applications of transformer paralleling will likely also exist. The application of paralleling methods and the determination and confirmation of optimum operation may further contribute to excessive tap-change operations. As described, changing system conditions are affected by automatic operations on the transmission and distribution systems, such as protective relay operations or load management techniques.