The paper addresses the question of how to deal with non-stationary power signals. The first part of the solution is at a fundamental level: the recognition that the thing being measured is known by some kind of label in a model. The label is attached to a some parameter in an equation, and is often identifiable by its position in the equation. The paper presents measurement as the act of solving the equation to find the value of the parameter. In other words, the equation is what metrologists term the measurand, and the measurement equipment must be designed around it. To measure a time-varying signal, in a world of digital measurements, one of the first questions that must be addressed is the relationship between the sampling window of the measurement system and the rate at which the signal is varying. A goodness of fit metric is identified. Several changing-frequency cases are examined.

}, keywords = {AA14-001}, doi = {10.1109/PESGM.2016.7741270}, author = {Harold Kirkham and Riepnieks, Artis} } @conference {1472, title = {The digital revolution in measurements}, booktitle = {2013 IEEE Power and Energy Society (PES) Innovative Smart Grid Technologies Conference (ISGT)}, year = {2013}, month = {02/2013}, pages = {1 - 6}, publisher = {IEEE}, organization = {IEEE}, address = {Washington, DC}, abstract = {This paper considers what it means to make a measurement, and the changes in measurement technology over the years. The impact of the latest changes, which have resulted in most electrical measurements being done digitally, is explored. It is argued that the process of measurement can be considered equivalent to one of data compression. The smart grid will certainly result in many more signals being made available, and therefore a great deal of data compression will be taking place. Measurements will be made in parts of the power system presently unmonitored, as well as parts that are already well covered by instrumentation. The smart grid engineer must decide what it means to have {\textquotedblleft}useful{\textquotedblright} information. Unless care is taken, the signal processing may furnish information that is not useful, and may not even make sense. The paper concludes by examining the possibilities of data compression from multiple separate signals.

}, keywords = {AA14-001, AARD, CERTS}, isbn = {978-1-4673-4894-2}, doi = {10.1109/ISGT.2013.6497875}, author = {Harold Kirkham} }