Papers by Helko Van Den Brom
2016 IEEE International Workshop on Applied Measurements for Power Systems (AMPS), 2016
In distribution networks, the data redundancy is usually assumed to be an inevitable bottleneck o... more In distribution networks, the data redundancy is usually assumed to be an inevitable bottleneck of traditional grid control and operation. Recently, the availability of smart meter data in distribution systems has provided an opportunity to improve the observability. As for the medium-voltage (MV) distribution system, there is an increasing interest to use the spatially aggregated smart meter data from low-voltage (LV) feeders in the state estimation, instead of inaccurate pseudomeasurements. However, good performance of state estimators requires good knowledge of the available measurements, in terms of both the mean value and the associated uncertainty. Hence, this paper intends to pave a new way of utilizing and aggregating smart meter data for the purpose of state estimation in the MV distribution system, in a concrete and reliable manner. The feasibility of the proposed method is verified on the IEEE European Low Voltage Test Feeder with a set of real-world smart meter data. Simulation results show that the utilization of aggregated smart meter data is able to improve the accuracy of load modelling of three-phase transformers.
IEEE International Symposium on Electromagnetic Compatibility (EMC Europe), 2019
Previous studies regarding static energy meter errors under non-sinusoidal load conditions have s... more Previous studies regarding static energy meter errors under non-sinusoidal load conditions have shown that these meters can produce erroneous readings. This paper describes an investigation done using loads consisting of a commercial lighting dimmer in combination with either a resistive heater or an array of various energy-saving lamps. Dimmer impedance and phase firing angle were gradually adjusted to change load conditions. Several meters showed dramatic variations in metering error under different load conditions. In the most extreme case, metering errors ranged from five times the energy consumed by the load to registering almost no energy. Though perhaps not typically found in households, the load combinations used in this study were able to highlight sensitivities of different static energy meters to changes in load conditions.
Measurement, 2025
The adoption of dc architectures for electricity distribution has been increasingly considered to... more The adoption of dc architectures for electricity distribution has been increasingly considered to reduce the number of energy conversions and to exploit their inherent ability to cope with peaks in energy supply and demand. Furthermore, dc systems have been commonly and widely adopted for high-voltage transmission systems and public transport for many years. Despite this, the Power Quality (PQ) assessment in dc power networks is still unstandardized. In the scientific literature, various indices have been proposed for the quantification of dc PQ. However, not all the aspects encountered in practical applications are adequately accounted for, and their effects regarding the impact on the measurement results are not fully analysed. This paper focuses on signal processing for the analysis of PQ of dc networks in stationary or quasi-stationary conditions aimed at compatibility level assessment. The influence quantities that affect the measurement results of the most commonly adopted procedures for determining the PQ index determination are identified and modelled, and their impact is analytically calculated. Advanced signal processing methods, suitable to be adopted in standards for dc PQ compatibility level surveys, are proposed to improve the accuracy and reliability of results. The rationality and effectiveness of the proposed procedures are shown with analytical calculations and in real measurement situations.
2024 International Instrumentation and Measurement Technology Conference, Glasgow, UK, 2024
Low-voltage DC microgrids are becoming more widely acknowledged as a viable option as local exten... more Low-voltage DC microgrids are becoming more widely acknowledged as a viable option as local extensions of the conventional AC distribution grid. Consequently, consistent definitions and measuring techniques of the parameters and criteria defining the power quality of these DC microgrids are needed, analogous to the traditional standards for AC electricity. An open issue in this aspect is the lack of available measurement results in real-world situations. In this paper, the results of a power quality measurement campaign performed in a unipolar 700 V DC microgrid in an open parking garage with currents up to 35 A are presented.
Energies, 2023
The growing use of renewable energy sources and sustainable technologies has increased the attrac... more The growing use of renewable energy sources and sustainable technologies has increased the attractiveness of low-voltage DC distribution grids. Despite initial research and standardization work, the definition of power quality (PQ) issues and their related compatibility levels in DC grids and the related measurement techniques remain in their infancy. The lack of available measurement results obtained in real-world situations is a major shortcoming. In this paper, the results of a measurement campaign obtained in a configurable bipolar 350 V/700 V DC microgrid in an urban environment are presented. Voltage and current signals were registered continuously at different positions in the microgrid with a sampling rate of 500 kSa/s while changing the configuration of the microgrid; the resulting data were analyzed afterwards, with a focus on DC voltage and current variation, ripple, and spectral analysis. The measurements were taken with custom-designed metrology-sound measurement equipment. The measurement results provide input to the development of DC PQ analysis tools and the standardization of DC PQ measurement methods. Furthermore, the experience obtained will be beneficial for utility companies and regulatory authorities for reliable planning-level and compatibility-level surveys.
A quantum standard for sampled electrical measurements - main goals and first results of the EMRP project Q-WAVE
29th Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014
ABSTRACT
2004 Conference on Precision Electromagnetic Measurements, 2004
The European JAWS project addresses the lack of instrumentation and knowledge for accurate and tr... more The European JAWS project addresses the lack of instrumentation and knowledge for accurate and traceable measurement and generation of altemating (AC) voltage with arbitrary waveforms. The objective is to develop a standard based on a Josephson Arbitrary Waveforn Synthesizer (JAWS), a precise instrument that links the generated voltage to the Josephson effect, which in turn relates the voltage to fundamental constants and a frequency. The standard aims at synthesized voltages up to 1O mV, frequencies up to 10 kIHz and uncertainty smaller than 1 part in 1 This paper reports on the progress in developing tie key components for JAWS.
IEEE Transactions on Instrumentation and Measurement, 2003
The European COUNT project exploits two complementary single electron tunneling devices for use i... more The European COUNT project exploits two complementary single electron tunneling devices for use in electrical current metrology: a single electron pump as a current source and a single electron counter as a current meter. An electron pump has been developed with on-chip resistors in order to suppress cotunneling. The intended accuracy is 1 ppm for a current of a few picoampere. Apart from being a quantum current standard, the electron pump could also be the basis of a capacitance standard. A coaxial tunable cryogenic capacitor of 1 picofarad has been developed for this purpose. A passive electron counter based on a single electron transistor embedded in a resonant tank circuit has been further investigated and developed in order to reach both high sensitivity and high counting speed. The intended accuracy is 10 ppm for a current of a few picoampere.
Accurate Measurements of Energy, Efficiency and Power Quality in the Electric Railway System
2018 Conference on Precision Electromagnetic Measurements (CPEM 2018), 2018
This paper describes a new EU co-funded project on metrology for smart energy management is elect... more This paper describes a new EU co-funded project on metrology for smart energy management is electric railway systems (MyRailS). The project involves 7 national metrology institutes, 3 universities and 6 railway companies. Research focusses on the following topics: i) new calibration facilities for energy meters on-board installed, ii) power quality monitoring systems, iii) accurate estimation of the saved energy by the installation of new reversible substations (RSS) and iv) by the adoption of eco-driving strategies.
Three-phase state estimation in the medium-voltage network with aggregated smart meter data
International Journal of Electrical Power & Energy Systems
Abstract In distribution networks, the lack of measurement data is usually thought to be an inevi... more Abstract In distribution networks, the lack of measurement data is usually thought to be an inevitable bottleneck of conventional grid operation and planning. Recently, the availability of smart meters in the distribution network has provided an opportunity to improve the network observability. In medium-voltage (MV) distribution networks, there is an increasing demand to use aggregated smart meter data for the state estimation, instead of adopting pseudo-measurements with a low level of accuracy. However, the performance of an estimator requires good knowledge of the available measurements, in terms of both expected values and associated uncertainties. Therefore, this paper intends to firstly pave a new way of utilizing smart meter data gathered from the low-voltage (LV) feeders in a concrete and reliable manner. For the purpose of state estimation in MV distribution networks, smart meter data is to be processed through three steps: phase identification, data aggregation and uncertainty evaluation. The feasibility of the proposed method is verified on the IEEE European LV Test Feeder with a set of real-world smart meter data. Afterwards, the influence of the aggregated smart meter data on the three-phase state estimation are investigated on the modified IEEE 13-node test system and IEEE 34-node test system. Simulation results show that the effect of aggregated smart meter data on the accuracy of state estimators is dependent on both the accuracy level of the aggregated data and the measurement configuration in the network. Furthermore, the use of aggregated smart meter data is shown to be able to provide improved state estimation.
2012 Conference on Precision electromagnetic Measurements, 2012
This paper describes the first results of an experiment aiming to determine the frequency depende... more This paper describes the first results of an experiment aiming to determine the frequency dependence of a cryogenic vacuum-gap capacitor between 0.01 Hz ('DC') and 1 kHz (AC). The AC-'DC' difference of the vacuum-gap capacitor is measured as a function of temperature, and the measured change of around 23 F/F between 273 K and 4 K agrees well with an extrapolation of earlier measurements on the same capacitor between 100 Hz and 1 kHz. The results also seem to support estimates that the AC-'DC' difference of this capacitor is well below 1 F/F at 4 K.
High-current AC current transformer calibration using an automated sampling system
2012 Conference on Precision electromagnetic Measurements, 2012
ABSTRACT A measurement setup is developed for the accurate ratio measurement of AC current transf... more ABSTRACT 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 digitizers for sampling of the secondary current signals and step-down transformers with a large number of current ratios. This allows for accurate comparison of CTs even when their nominal ratios are not equal.
29th Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014
A sampling current ratio bridge has been developed, tested and validated for the accurate complex... more A sampling current ratio bridge has been developed, tested and validated for the accurate complex ratio measurement of AC current transducers for primary currents up to 10 kA with expanded uncertainties of 5 • 10 -6 in magnitude and 5 µrad in phase (k = 2). A unique property of the system is the use of digitizers for sampling of the secondary current signals and step-down transformers with a large number of current ratios. This allows for the accurate calibration of a large variety of different current transformers and other types of current transducers.
Measurement of the harmonic impedance of the aggregated distribution network
2016 17th International Conference on Harmonics and Quality of Power (ICHQP), 2016
This paper presents a method for measurement of the harmonic impedance of an aggregated distribut... more This paper presents a method for measurement of the harmonic impedance of an aggregated distribution network using multiple Phasor Measurement Units (PMUs) with the additional capability of synchronized voltage and current spectrum measurement. The perturbations of the harmonic voltages which originate from the higher voltage levels are distinguished based on the measurements from multiple busbars, and used as the input for the calculation. Results of a test case using measurements from a 50 kV network are given to illustrate the method.
International comparison of quantum AC voltage standards for frequencies up to 100kHz
Measurement, 2012
ABSTRACT This paper presents results of an international comparison of two quantum AC voltage sta... more ABSTRACT This paper presents results of an international comparison of two quantum AC voltage standards based on pulse-driven Josephson arrays. The two systems differ in several hardware and software characteristics as well as in the level of automation, features which can influence the accuracy of transferring the quantum-standard voltage value to a calibrated instrument. The comparison was performed at 100 mV, 20 mV and 12 mV, at frequencies between 2.5 kHz and 100 kHz. An electronically-aided thermal transfer standard was used as a travelling standard. At the most accurate voltage and frequency point, 100 mV at 2.5 kHz, both laboratories agreed to better than 1 part in 106.
Josephson Arbitrary Waveform Synthesizer: Electronics for a Quantum Standard for Ac Voltage
A new primary standard for AC voltage based on pulse driven Josephson junction arrays is under de... more A new primary standard for AC voltage based on pulse driven Josephson junction arrays is under development. In this paper, preliminary spectral measurements and simulations are presented on a fast switching multiplexer unit built for the high precision synthesis of arbitrary waves. First order delta-sigma modulation is used to represent the wave to be synthesized. The first results are promising with respect to the conditions for high precision filtering of the quantization noise, i.e. a high signal-to-noise ratio is expected for the demodulated signal.
Electrical Power Quality and Utilisation. Journal, 2013
Standardization has contributed significantly to comparable analysis methods for power quality pa... more Standardization has contributed significantly to comparable analysis methods for power quality parameters. However, in order to have undisputable results, the measurement values themselves should also be comparable. This can only be achieved by traceability to international measurement standards. For this reason, at VSL, the Dutch national metrology institute, a fully traceable reference setup was developed for calibration of power quality analyzers. In this paper, we show the calibration results of the critical components of the reference setup, we demonstrate its applicability by test measurements on the public low-voltage supply system for specific parameters, and show its ability to simulate and generate events that can be detected and analyzed by both the equipment under test and the reference setup.
Design of a non-invasive current sensor for application on high voltage lines
29th Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014
The propagation of Power Quality (PQ) phenomena through distribution networks is dependent on a n... more The propagation of Power Quality (PQ) phenomena through distribution networks is dependent on a number of parameters, including the characteristics of the disturbance source, impedances and configuration of the network and behaviour of loads and generators in the analysed area. Due to the large numbers of network users, estimation of disturbance levels in the network includes a large number of uncertainties. This paper proposes a method for analysing the propagation of PQ phenomena through the distribution network based on wide-area field measurements. In the future, the method will be used to analyse the data obtained from Live-Lab the permanent field experiment of the Dutch DSO Alliander. The analysis takes into account the state of the network, loading of substations and measurement uncertainty.
Results of an International Comparison of Instrument Current Transformers up to 10 kA at 50 Hz Frequency
Traceability of the current ratio is crucial for the measurement of electrical energy in revenue ... more Traceability of the current ratio is crucial for the measurement of electrical energy in revenue metering. A comparison of the AC current ratio was therefore performed within EURAMET in the time period 2012 - 2016, using a precision CT as the traveling device. The Czech Metrology Institute (CMI) as coordinator processed the measurement results of the 15 European participating laboratories. The comparison of the results for transformer ratios of (4, 5, 6, 8, 10) kA/5 A at 15 VA burden and (4 and 10) kA/5 A ratios at 5 VA burden indicates good agreement between the participating laboratories. The main differences are found for phase displacement, at least in part due to instability of the traveling standard.
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Papers by Helko Van Den Brom