How a large power transformer works
345/138 kV · 300 MVA (illustrative) · lead times ~128 weeks · prices up ~77% since 2019
A steel core and copper windings under oil step voltage down from the transmission grid; radiators and fans carry off the heat. Watch a heat-wave day push one past nameplate, and see why insulation life and spares matter. Every number comes from one model.
Sources: POWER Magazine, “Transformers in 2026: shortage, scramble or self-inflicted crisis?” (Jan 2026), citing Wood Mackenzie: power transformers averaged 128 weeks and step-up units 144 weeks in Q2 2025; prices up 77% and 45% since 2019; a roughly 30% supply gap in 2025. Temperature and aging use IEEE C57.91's method; the unit's rating, losses and the day's load and weather are illustrative. Others on this approach: Siemens Energy, Prolec GE.