How do I calculate the power lost (heat loss) of a transformer? I have a 3750 kVA, 13.2kV-4.16kV, 1200 Amp, indoor transformer. I was trying to calculate the power factor, but i kept getting 4.224, and i know it's supposed to be less than 1. Also, i was curious how to calculate the power. I know it's voltage multiplied by current, but i wasn't sure which voltage value to use. Any info would be extremely helpful.