PNNL

Abstract

Measuring instruments used in power systems will continue to report their results, even when there is a fault in the system. At such a time, the quality of the measurement is decreased, and the uncertainty of the value is increased. The uncertainty should be reported, but it rarely is. While power engineers have seemingly come to trust the results of such measurements without an uncertainty statement, in any case there is a fundamental problem with quantifying the uncertainty. The problem is not limited to power systems, though faults make it more evident. Uncertainty of the kind caused by a faulted power system can be considered definitional uncertainty, and that is normally evaluated statistically. It is not possible to perform statistics unless the measurement can be repeated at least a few times, and that is not an option outside the laboratory. This paper examines the matter from the viewpoint of measurement theory, and suggests a direction for some future work.