Evaluation of uncertainties in testing of losses in power transformers using GUM-S1

This paper describes the application of the methodology established in the Supplement 1 to the Guide to the Expression of Uncertainty in Measurement for the evaluation of uncertainties in the measurement of losses in power transformers. Also presented is the criterion for the validation of the software used for these measurements based on the original Guide. This additional method was developed since the original one presents some limitations, especially those related to the degree of nonlinearity of the measuring models. The results suggest that this degree of nonlinearity is such that the application of this supplementary method is necessary.