An Application of Uncertainty Calculations to Distribution Transformer Loss Testing

The classical method of uncertainty calculation is presented as a means to evaluate the requirements for accurate measurement in performance testing of electrical equipment. Specific formulas are derived for transformer load loss and no-load loss measurements. The resulting expressions are then used to illustrate how the uncertainty calculation can provide insight into testing problems. A similar technique could be applied to any equipment performance test. The classical uncertainty calculation does not account for gross errors and mistakes. These illegitimate errors must be detected and controlled through an auxiliary system, which normally involves some form of computer in high volume, production line testing.