285 MW Interconnection between Unit 3 Generator and Unit 2 Main Transformer in Soto de Ribera Coal Power Plant

Abstract

Soto de Ribera Coal Power Plant had two Generatio Units called Unit 2 and Unit 3. Both Units consist of a Generator (SR3, generating energy at 20 kV and SR2, generating energy at 22 kV) that produces the energy and a Main Transformer (MT2, with Tr. Ratio of 132/22 kV and MT3, with Tr. Ratio of 400/20 kV) that steps-up the voltage to the grid level. At the end of 2015, Unit 2 Generator got to the end of its useful life and it should be dismantled, but its Main Transformer (MT2) could continue operating, as it had not reached its useful life. In order to be able to export energy through MT2, it was necessary to make an interconnection between SR3 Generator and MT2 Transformer, being able to export energy through the 132 kV or the 400 kV grids (but not simultaneously) with just one Generator.