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.

%B 2016 IEEE Power and Energy Society General Meeting (PESGM) %I IEEE %C Boston, MA, USA %P 1 - 5 %8 07/2016 %R 10.1109/PESGM.2016.7741270 %0 Conference Paper %B 2016 Conference on Precision Electromagnetic Measurements (CPEM 2016) %D 2016 %T Error correction: A proposal for a standard %A Harold Kirkham %A Riepnieks, Artis %A So, Eddy %A McBride, Jim %K AA14-001 %XSome of the errors in transducers such as instrument transformers can be corrected as part of the digital processing for the measurement. The instrument transformer can be characterized in such a way that allows the Transducer Electronic Data Sheet of IEEE Std 1451 to transfer the information to the measurement system. A modification would allow the measurement system to perform a high-quality self-calibration whenever a transducer was replaced. That levies requirements on the characterization accuracy of the instrument transformer.

%B 2016 Conference on Precision Electromagnetic Measurements (CPEM 2016) %I IEEE %C Ottawa, ON, Canada %P 1 - 2 %8 08/2016 %R 10.1109/CPEM.2016.7540557 %0 Conference Paper %B 2016 57th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON) %D 2016 %T Rate of change of frequency measurement %A Riepnieks, Artis %A Harold Kirkham %K AA14-001 %XThe measurement of amplitude, frequency, rate-of-change of frequency, and phase of an alternating waveform is the purpose of the Phasor Measurement Unit, PMU. Performance requirements, specified by standard, are tested with constant values of each of these parameters, using a synthetic waveform with values that are precisely known. However, device performance requirements are not defined during transitions from one set of values to another. We investigated measuring across a transition. Our investigation revealed something interesting about ROCOF, the rate of change of frequency. We conclude that until power system noise is better understood, the attempt to measure real-world ROCOF during a short PMU measurement window should be abandoned, but measurements during calibration transitions might still be possible and need not be excluded from the standard.

%B 2016 57th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON) %I IEEE %C Riga, Latvia %P 1 - 5 %8 10/2016 %R 10.1109/RTUCON.2016.7763110 %0 Conference Paper %B 2016 57th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON) %D 2016 %T Students' simple method for determining the parameters of an AC signal %A Harold Kirkham %A Riepnieks, Artis %K AA14-001 %XThe paper sets aside details of instrumentality to reveal the nature of the problem addressed by measurement. Its title is based on the title of a 1894 paper by Prof. W.E. Ayrton and his student H.C. Haycraft. They described a new and simplified method of measurement to improve the teaching of their underlying topic, and that is the goal of this paper. In the work described here, the measurand is taken to be an equation representing an alternating signal, and the declared values of the measurement are estimates of the parameters of the equation. It is shown that the parameters of the ac signal can be found by curve-fitting. Lessons can be drawn about the role of noise in measurement and about the very meaning of the result.

%B 2016 57th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON) %I IEEE %C Riga, Latvia %P 1 - 7 %8 10/2016 %R 10.1109/RTUCON.2016.7763125