Intercomparison of Calibration Systems for AC Shunts Up to Audio Frequencies

Calibration of Rogowski coils at frequencies up to 10 kHz using digital sampling

“…The ac shunt operated at currents not larger than 2 A, which is 20% of its rated current, and its self-heating was consequently 25 times smaller. The calibration of the ac shunt [21] has shown uncertainties (k =2)for both in-phase and quadrature components of less than 20 · 10 −6 in the frequency range up to 10 kHz. To estimate the impact of the DSS input impedance on the measurement results, the input impedance was modeled as a simple parallel connection of a resistance and a capacitance.…”

AC power standard using a programmable Josephson voltage standard

“…The 5 A applied current is converted to 0.5 V using a 3-stage, amplifier-aided current transformer T1 [4] with resistive burden. At 60 Hz, the residual magnitude and phase errors of the transducer output voltage at full-scale 5 A input current are less than 2 μV/V and have been determined by comparing it to a 0.1 Ω temperature-controlled standard shunt [7] using a system similar to the one described in [8].…”

Dual Phase Lock-In Amplifier with Photovoltaic Modules and Quasi-Invariant Common-Mode Signal

“…In measuring small voltage deviations of about 1 µV and lower, it is important to separate a useful signal from noise. This problem is relevant to the metrological support of measuring transducers, such as inductive voltage dividers [1][2][3][4], current shunts [5][6][7], current transformers, current clamps [8,9] for AC voltage measurements [10][11][12][13], vibration measurements of MEMS gyroscopes, accelerometers [14][15][16] and other sensors [17][18][19][20][21][22][23][24]. The measurement of small voltage deviations between the amplitudes of two AC signals in wide frequency and voltage ranges is performed by using lock-in amplifiers with the differential input as a comparator (null-indicator and null-detector) [25,26].…”