In support of the European Commission’s assessment of eco-design requirements for Distribution and Power Transformers, CLASP has undertaken this study investigating the relationship between the manufacturer’s selling price and efficiency for large power transformers.

This is the third transformer design report prepared by CLASP for this regulatory proceeding (i.e. DG Enterprise Lot 2: Distribution and Power Transformers), the others being a report on three oil-immersed transformers in August 2010 and a report on two cast-coil dry-type transformers in March 2011.

This report presents the design results of three large power transformers:

• 25 MVA three-phase oil-immersed, 150/20 kV with on-load tap changer
• 100 MVA three-phase oil-immersed, 220/23.8 kV with on-load tap changer
• 63 MVA three-phase oil-immersed, 150/20 kV with on-load tap changer

Understanding how the price of transformers increases as the efficiency improves is important because it enables an accurate assessment of life-cycle costs and associated payback periods. Generally, a transformer becomes more expensive as efficiency improves because it is incorporating either more material and/or better quality materials. 

The designs presented in this report were prepared by Professor Antonio Bossi and Professor Angelo Baggini. The megavolt-ampere (MVA) ratings, voltages and other design parameters were selected to try and be representative of models installed in Europe.