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Rietveld G.,Dutch National Metrology Institute
IEEE Transactions on Instrumentation and Measurement | Year: 2013

An extremely sensitive vibrating reed electrometer is built, which has attocoulomb charge resolution and subattoampere current resolution within a 1-min measurement. The input leakage current of the setup is typically less than 1 aA with values as low as 0.12 aA, which is less than 1 electron/s. Allan deviation analysis shows that the lowest standard deviation that can be achieved in current measurements is 0.065 aA with a 3-h integration time. Crucial for this extreme sensitivity and low leakage current was the development of an input measurement stage with only vacuum-gap capacitors. The stability and sensitivity of this new electrometer make it suitable for accurate low-frequency characterization of vacuum-gap capacitors as for example used in the electron counting capacitance standard experiment. As a first step toward such a study, the internal vacuum-gap feedback capacitor of the electrometer was measured as a function of applied charge and for different heat treatments resulting in changing surface layers of the capacitor plates. © 2012 IEEE. Source

Rietveld G.,Dutch National Metrology Institute | Braun J.-P.,Federal Office of Metrology | Martin R.,Laborarorio Central Official de Electrotecnia | Wright P.,National Physical Laboratory United Kingdom | And 4 more authors.
IEEE Transactions on Instrumentation and Measurement | Year: 2015

Grid operators are facing a significant challenge in ensuring continuity and quality of electricity supply, while more and more renewable energy sources are connected to the grid. The resulting evolvement of so-called smart grids strongly relies on the availability of reliable measurement data for monitoring and control of these grids. This paper presents an overview of the results achieved in recent smart grid metrology research in Europe, aiming to realize the required metrology infrastructure for ensuring security and quality of supply in future smart electrical grids. A consortium of 22 metrology and research institutes has made significant steps in modeling of smart grids, enhancement of the revenue metering infrastructure, performance and evaluation of onsite power quality campaigns, and the development of a metrological framework for traceability of smart grid phasor measurements. © 1963-2012 IEEE. Source

Rietveld G.,Dutch National Metrology Institute | Jol L.,Dutch National Metrology Institute | Van Den Brom H.E.,Dutch National Metrology Institute | So E.,National Research Council Canada
IEEE Transactions on Instrumentation and Measurement | Year: 2013

A measurement setup is developed for the accurate ratio measurement of ac current transformers (CTs) for primary currents up to 5 kA. A unique property of the system is the use of high-quality digitizers for sampling of the secondary current signals and step-down transformers with different current ratios. This allows for accurate comparison of CTs even when their nominal ratios are not equal. The calibration results of the key components in the setup show that the sampling current ratio bridge has a ratio uncertainty of better than 2 μ A/A in magnitude and 0.8 μrad in phase for CT-under-test current ratios that do not differ by more than a factor of 5 from one of the ratios in the reference CT. The linearity of the bridge for input currents changing between 1% and 120% of nominal input current is better than 4 μ A/A in magnitude and 0.5 μ rad in phase. © 2013 IEEE. Source

Houtzager E.,Dutch National Metrology Institute | Rietveld G.,Dutch National Metrology Institute | Van Den Brom H.E.,Dutch National Metrology Institute
IEEE Transactions on Instrumentation and Measurement | Year: 2013

This paper describes a power measurement setup that is able to measure power up to the MHz region. The setup consists of a commercial digitizer together with a switch unit, and buffer amplifiers to alternately measure the voltage and current channel. A reference AC voltmeter provides an absolute reference by simultaneous measurement of the rms voltage of one channel, which significantly reduces the need for flat frequency response of the setup. The method described in this paper makes complex voltage ratio measurements possible in the range of 50 Hz up to 1 MHz with an uncertainty of a few parts in 10 6 and in addition can be applied in wideband power measurements. Using our new method, the frequency response of cables and several other components is no longer a limiting factor for power measurements up to 1 MHz. © 2013 IEEE. Source

Rietveld G.,Dutch National Metrology Institute | Van Der Beek J.H.N.,Dutch National Metrology Institute
IEEE Transactions on Instrumentation and Measurement | Year: 2013

A high-ohmic bridge for automated resistance measurements in the range between 1 MΩ and up to and above 100 TΩ is described. Whereas similar setups reported so far use only current null detection, the present system developed at VSL can use either voltage or current null detection. We compare the two null detection methods and find no significant difference between the methods over the resistance range between 10 MΩ and 100 GΩ. Voltage null detection is more accurate for resistance values below 10 GΩ at 10 V measurement voltage, whereas for resistance measurements above 100 GΩ current null detection should be used. Careful automation and refinement of the measurement procedure lead to excellent results and uncertainties. For example, the measurement of the 1:100 ratio of the series and parallel connection of a 10 × 100 M Ω Hamon device agrees within (0.5 ± 0.4) μ Ω/Ω with the nominal Hamon ratio. The total measurement uncertainty at 1 G Ω equals 1.7 μΩ/Ω(k=1), which has been confirmed in a recent international comparison. © 2013 IEEE. Source

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