At the National Institute of Metrological Research a convenient setup to verify the DMMs linearity has been developed. It consists in a top-class calibrated DC Voltage calibrator supplying directly the DMMs under test. Some Keysight 3458A, a Fluke 8508A and an 8588A DMMs are being enrolled in the tests. This setup is also compared with another setup with a Digital Analog Converter (R – 2R DAC) in place of the calibrator. The DMMs linearity is being verified both when DMMs are just switched on and at thermal regime. The interference of the input stages of the DMMs connected in parallel during the linearity measurements and the linearity by inverting the plug of one of the DMMs connected in parallel are currently under verification.

The paper describes design of a new multirange AC resistive voltage divider (RVD) for input voltage up to 1 kV for measurement of LF power and power quality parameters. Two prototypes were constructed and characterised in terms of temperature dependence, power dependence of gain and phase errors and AC transfer. The new RVD reached phase change below 0.5 μrad and gain change below 8 μV/V at 53 Hz for voltage step from 100V to 1 kV with time constant below 2.5 minutes. Voltage dependence and DC ratio stability are under evaluation.

In modern power systems, the measurement infrastructure represents the backbone of any monitoring and control application. Indeed, the everincreasing penetration of renewable energy sources and distributed generation has produced an operating scenario prone to instability and rapid variations. Power quality assessment procedures must evolve in order to address these challenges. In this regard, the use of phasor measurement units (PMUs), which measure the phasor values of current and voltage with high precision time stamp, presents a significant opportunity to evolve current power quality assessment procedures. This position paper suggests the inclusion of novel PMU-based metrics in order to extend quality power assessment procedures at each sensitive network node towards the further use of aggregated data at both local and/or central level. The proposed PMU-based metrics will provide a better description of the behavior of the system, allowing to take control actions as part of the extended quality power assessment procedures.

The diffusion of renewable energy sources is heavily affecting all aspects of modern power grids equipped by distributed energy resources and Battery Energy Storage Systems. Suitable Key Performance Indicators (KPI) have been developed, to find optimal storage capacity and control algorithms, which are resulted to be really dependent on data recording time interval. The aim of this paper is to analyze, on real data, which effect the time resolution of measurement data has on energy KPIs and to investigate how to select a proper compression algorithm to enhance the efficiency of the data collection process. Results shows that the KPI will be underestimated by the 40% if the sampling time rises from 5 s to 10 s, making lossy algorithms not interesting. Furthermore, lossless compression algorithms are effective but the tuning of those algorithms is all but intuitive.

This paper describes the experimental application of the AC quantum voltmeter, developed at PTB, for impedance ratio measurements at voltages up to 5 V and frequencies up to 1 kHz, as continuation of previous work. In such an application the AC quantum voltmeter is not directly measuring the output voltage of an AC source (as in ordinary use), but measures the voltage drop on the impedance, raising the requirements for synchronisation, grounding, and load influence of the used AC voltage source. Therefore, three types of AC sources were tested, a calibrator Fluke 5720A, a new version of an Aivon DualDAC3, and PTB’s PDWQ mk21. As impedances, two temperature stabilized Vishay resistors of nominal values of 10 kΩ are used. They are measured in a potentiometric way, i.e., the AC quantum voltmeter measures the RMS voltages on each resistor in a time sequence. The measurement results for different setups are described and presented.