That's a great comminity here. Now I have a problem with ambient temperature rise. Lets describe the problem. For the power transformers the power of transformer is related with ambient temperature. And IEC 354 shows how it is calculate for a transformer . But its so complex and I couldnt convert it to computer program. Can anybody know the power of transformer acc to temperature. For example: Design temperature of a power transformer : 40°C Power of the transformer at 40°C : 25000KVA What will be the power of this transformer at the temperatures of 20°, 30° and 50°C. Assuming hot spot temp is 118°C Thanks so much .