Category: student projects

As of this newsletter, we have added a new section. In this section, we want to introduce you to students at Dutch Technical Universities and Universities of Applied Sciences who are studying our field of expertise. Each newsletter will feature a student or PhD candidate introducing themselves and explaining what their research entails. With this, we hope to build a bridge between the business community and universities. If you would like to get in touch with these students, you can do so via the following email address: info@emc-esd.nl.

Tom Hartman – Meter EMI, University of Twente

Tom Hartman was born in August 1995 in Rossum. In 2016 he obtained his bachelor's degree in Electrical Engineering at the University of Twente. In 2018 he obtained his master's degree in "Electrical Engineering", also at the University of Twente.

Since August 2018, he is working as a PhD candidate at the Power Electronics group (formerly Telecommunication Engineering group) at the University of Twente, in Enschede. Tom is working on a project about Electromagnetic Interference on Static Electricity Meters. In this project, Tom is working on improving the digital signal processing techniques used for multichannel TDEMI measurements.

In modern households, energy consumption is measured using static energy meters, which are called smart meters when a communication link is added. These smart electricity meters are currently widely deployed by energy companies throughout Europe. In recent studies, large deviations in some meter readings have been reported. This is due to electromagnetic interference affecting the energy measurements of static energy meters. Lower readings of static energy meters have been reported in many publications, but higher readings were also found when commercial equipment was used as a load in combination with a dimmer [1]. In the most extreme case, deviations between -61% and +2675% were found when using a standard mains supply [2]. To assess the underlying problem behind the static meter deviations, a measurement technique needs to be developed to characterize the currents to which static meters are typically exposed [3]. Previous studies have shown that the reading of static meters is erroneous when impulsive currents are drawn from the mains, this can happen even with standalone commercial equipment [4][5].

The measurement bandwidth of the static energy measurements is increased. This is done to capture all harmonic components introduced by non-linear loads and distributed generators. This increases the complexity of the measurement electronics and makes them sensitive to electromagnetic interference.

A recently accepted article for publication in the “IEEE Transaction on Electromagnetic Compatibility” proposes to change the accuracy paradigm by focusing on fundamental active power and only the lower harmonic components for energy measurement. This should allow to simplify the electronics and focus on making them more robust against electromagnetic interference. Using the orthogonality of the power supply via Parseval’s theorem, theoretical analysis, simulations and measurements on power calculations are addressed. As a result, the principle of fundamental active power is presented. The paper shows that a perfect power measurement can be achieved with a clean 50 Hz supply voltage, regardless of the nonlinear current. Even at the most extreme allowed harmonic distortion of the voltage and current as stated in the international standards EN 50160 and IEC 61000-3-2, more than 97.5 % of the active power is contained in the fundamental active power. A negligible active power is contained in the higher frequency components. This error margin is within the limits of the electricity meters. The article will soon be available for public viewing at http://empir.npl.co.uk/meteremi/publications/.

[1] F. Leferink, C. Keyer, and A. Melentjev, “Static Energy Meter Errors Caused by Conducted Electromagnetic Interference, IEEE Electromagnetic Compatibility Magazine, vol. 4, pp. 49–55, 2016.

[2] B. ten Have, T. Hartman, N. Moonen, C. Keyer, and F. Leferink, “Faulty Readings of Static Energy Meters Caused by Conducted Electromagnetic Interference from a Water Pump,” in International Conference on Renewable Energies and Power Quality (ICREPQ'19), Tenerife, 2019, pp. 15–19.

[3] T. Hartman, M. Pous, MA Azpúrua, F. Silva and F. Leferink, “On-site Waveform Characterization at Static Meters Loaded with Electrical Vehicle Chargers,” 2019 International Symposium on Electromagnetic Compatibility – EMC EUROPE, Barcelona, Spain, 2019, pp. 191-196, doi: 10.1109/EMCEurope.2019.8871469.

[4] B. ten Have, T. Hartman, N. Moonen, and F. Leferink, “Inclination of fast changing currents effect the readings of static energy meters,” in 2019 International Symposium on Electromagnetic Compatibility – EMCEUROPE, 2019, pp. 208–213.

[5] J. Dijkstra, T. Hartman, N. Moonen and F. Leferink, “An AC Controlled-Current Load for Controllable Waveform Parameters to Quantify Static Energy Meter Errors,” 2020 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI), Reno, NV, USA, 2020, pp. 472-477, doi: 10.1109/EMCSI38923.2020.9191617.