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A new reference resistive-capacitive voltage divider is presented in this paper, operating in dc and ac from 10 to 200 kHz. The ratio error is lower than 0.1% and the phase error is lower than $400~\mu $ rad (1.375’) at 100 kHz. The divider is stable and repeatable. The scale factor (SF) and the phase error repeatability, tested in 24-h continuous measurements repeated during 15 weeks, show an SF variation lower than 80 ppm and a phase error variation lower than 20 $\mu $ rad. This allows one to define a calibration matrix of the device bringing its relative measurement uncertainty lower than $0.5 \cdot 10^{-3}$. The divider calibration has been obtained with a step-up method, which could improve traceability in many laboratories and is described in this paper. The divider can be embedded in a calibration chain to test the accuracy of voltage transducers in the measurement of the ac voltage ripple, in the presence of a significant dc component, as it occurs in many power electronic systems. The voltage calibration chain is based on the use of the reference divider and a voltage injector, the secondary of which is placed in series with a stable dc source. By means of this calibration system, one of the best commercial voltage transducers on the market has been analyzed. This paper also highlights how the proposed voltage calibration chain could be used in perspective in a phantom power system for the development of a dc plus ac power standard. [ABSTRACT FROM AUTHOR]

To establish a single European railway area, the European Commission requires, by 2019, that energy billings shall be computed on the actual energy consumed. So, in the near future, all the trains shall be equipped with an energy measurement system, whose measurement accuracy should be assessed and periodically reverified, as required by EN 50463-2. As for every energy and power measuring system, the voltage and current transducers play a crucial role as their accuracy could determine the performance level of the entire measurement chain. To answer to this emerging need, this paper presents a calibration system allowing the accurate testing of dc voltage and current transducers, up to 6 kV and 300 A and up to 10 kHz. It is able to reproduce all the tests prescribed by EN 50463-2, but in order to characterize the transducers in actual operating conditions, a series of additional tests can also be performed using synthetic complex waveforms or even signals acquired on-board trains. The expanded uncertainty (level of confidence 95%) of the calibration system is 43 $\mu \text{V}$ /V and 24 $\mu \text{A}$ /A at dc and 520 $\mu \text{V}$ /V and 820 $\mu \text{A}$ /A at 10 kHz. Moreover, the calibration of two commercial voltage and current transducers, currently installed in the trains of an Italian operator, is presented. [ABSTRACT FROM AUTHOR]

This paper describes the application of GUM supplement 1 and supplement 2 in the intercomparison procedure of a group of four dc voltage reference standards. The results obtained are presented and according to these, the choice of a restriction is suggested to improve the uncertainty and avoiding the strong correlation of the estimated values. [ABSTRACT FROM AUTHOR]

This paper aims at characterizing and improving the metrological performances of current and voltage instrument transformers (CTs and VTs) in harmonic measurements in the power system. A theoretical analysis is carried out to demonstrate that, due to the iron core nonlinearity, CT and VT output signal is distorted even when the input signal is a pure sine wave. Starting from this analysis, a new method for CT and VT characterization and compensation is proposed. In a first step, they are characterized in sinusoidal conditions and the harmonic phasors of the distorted output are measured; in the second step, these phasors are used to compensate the harmonic phasors measured in normal operating conditions, which are typically distorted. The proposed characterization and compensation techniques are called SINusoidal characterization for DIstortion COMPensation (SINDICOMP). Several experimental tests, using high-accuracy calibration setups, have been performed to verify the proposed methods. The experimental results showed that the SINDICOMP technique assures a significant improvement of CT and VT metrological performances in harmonic measurements. [ABSTRACT FROM AUTHOR]

This paper presents an improved calibration setup for static bridge standards with a carrier frequency supply voltage in the frequency range between 225 Hz and 5 kHz. In the past, the small bridge differential voltage in the mV/V range was calibrated in two subsequent voltage ratio calibrations. However, this procedure is time-consuming and only works reliably if both voltages are stable over time. For this purpose, a new setup was developed that is able to measure the differential voltage of the bridge standard in one single measurement. This reduces the calibration time by approximately two thirds, thereby also reducing the uncertainty. [ABSTRACT FROM AUTHOR]