A simplified temperature model is presented to substitute for the traditional temperature measurement. First, the temperature model of a transformer, based on IEEE std. C57.91, is briefly reviewed and then a load assumption is proposed to simplify the temperature formula. Second, a test case from the appendix of IEEE C57.91 is used to indicate that the measured and calculated temperatures are nearly the same using the proposed method. Finally, error analysis illustrates that the simplified models can be an alternative way to calculate the transformer temperatures and the transformer elapsed life. (10 refs.)
