EMRP - Power&Energy: Next generation of power and energy measuring techniques

• Research unit: METAS
• Project number: 5213.08.FP.062

Key words (English)

Electrical power, power quality, digitizers, characterisation, methodology for PQ parameters measurements

Short description (English)

Society demands electricity supplies that are secure, sustainable and of high quality. In the next decade, Europe is facing potential energy shortages as oil and gas supplies run down and nuclear power facilities age. Pressure to reduce the green house gas emissions will lead to a requirement for more renewable energy generation, efficient appliances, energy management and improved electricity distribution efficiencies. Commerce will demand an electricity supply of the highest quality, free from momentary voltage interruptions or interference sources. This project will develop the necessary infrastructure to enable the measurement of the complex electrical parameters associated with power, energy and power quality to ensure that technologists, energy suppliers and regulators can work towards an energy secure future within a metrology framework.

The project is carried out by a consortium of sixteen National Metrology Institutes across Europe; it is partly funded by the European Community’s Seventh Framework Programme, ERA-NET Plus under Grant Agreement No 217257.

Project aims (English)

The project will undertake the following research and development:

• Design and build metrology grade digitisation hardware suitable for laboratory and on-site use suitable for measurement of signals ranging from three phase power to transients and impulses.
• Develop and characterize precision transducers for laboratory measurements of power and power quality.
• Formulate accurate sampling techniques and analysis algorithms in support of power quality including asynchronous sampling and noise reduction algorithms.
• Develop and characterize high current and high voltage transducers for non-invasive use on the high voltage grid.
• Apply of this new technology within a harmonised methodology for the traceable measurement of power quality parameters in the laboratory and on-site.

Abstract (English)

For the first aim, namely the characterization of the high resolution ADC, a test bench based on programmable a Josephson Voltage Standard has been developed. The set up enables both the analysis of the noise floor as well as the integral linearity of ADCs. The noise characterization is based on the Allan deviation. The linearity is achieve by a step wise triangular Josephson signal applied to the input of the ADC. As this source can be considered “exact”, any difference between the ADCs and the source levels can be at-tributed to the ADC?s errors.
The harmonized methodology for the power quality parameters measurements focused primarily on the measurement of harmonics and flickers emission of power loads. These are tests done routinely in the industry for the CE certification of products. The purpose of the harmonized methodology is to ensure that the traceability is achieved on an uniform basis across all NMI in Europe. This methodology could be used at METAS if it elects to provide such services.

Transfer and application (English)

The ADC test bench has been used to characterize two commercial ADCs as well as one developed by the National Physical Laboratory (NPL) for its power quality monitoring system. The tests consisted in a measurement of their noise floor and linearity. The key results are:
-The white noise level and 1/f cut off frequency have been precisely quantified
-For some ADC, the noise floor was shown to be dependent on sampling frequency
-The integral linearity of all ADCs were generally well within a few ppm
-Some ADCs exhibited hysteresis at very low frequencies.
These results proved very useful for other projects in the electricity section were these com-mercial devices are used on a daily basis. This test facility is also likely to be a valuable tool at METAS for the characterization of ADC new devices.

Publications / Results (English)

F. Overney, A. Rüfenacht, J.P. Braun, B. Jeanneret, P.S. Wright, “Characterization of Metrological Grade Analog-to-Digital Converters using a Programmable Josephson Voltage Standard”, to be published in IEEE Transactions on Instrumentation and Measurement, 2011