Oil-Immersed Power Transformer Overload Calculations by Computer

Application of overload ratings to power transformers is considered in the light of 30 years of operating experience. A comprehensive description is given of the philosophy of overloading, methods of calculation, transformer life curves, and a working computer program which incorporates these factors with increased accuracy and reduced engineering time. Recommendations are made regarding life curves, ambient temperature selection, resistance correction for temperature variations, and daily load-cycle evaluation.