Papers by Ernest Houtzager
Calibration of Commercial Test Sets for Non-Conventional Instrument Transformers
2017 IEEE International Workshop on Applied Measurements for Power Systems (AMPS), 2017
This paper describes the design and setup of different measuring systems for the calibration of c... more This paper describes the design and setup of different measuring systems for the calibration of commercial voltage and current transformer test sets for non-conventional instrument transformers. The calibration systems are recently developed at the national metrology institutes VSL, PTB, METAS and TUBITAK within the frame of the European project “FUTURE GRID — Non-conventional voltage and current sensors for future power grids”. The attained uncertainty of the calibration systems is in the order of 10 ppm and 10 μrad for testing the analogue non-conventional input and 20 ppm and 80 μrad for testing the digital (IEC 61850-9-2) input of the test set.
Losses constitute a significant part of the total cost of ownership of power transformers. Since ... more Losses constitute a significant part of the total cost of ownership of power transformers. Since these losses have an impact on the environment as well, the European Union has issued a regulation with regard to losses in power transformers, as part of the sustainable energy policies of the Ecodesign Directive. Already for many years, commercial power transformer loss measurement (TLM) systems are used by power transformer manufacturers for verification of the loss specifications of their products. With the new commission regulation, it is more than ever important to calibrate these TLM systems to assure and demonstrate an independently verified accuracy in the tests. Two approaches can be used in calibrations of TLM systems: a component and a system calibration approach. The latter has the advantage that all influence factors of the complete TLM system are taken into account in the calibration. Using state of the art reference equipment, in both approaches calibration accuracies can...
New references for HVDC metering
Power transformer efficiency measurements are a crucial part of the acceptance tests of a power t... more Power transformer efficiency measurements are a crucial part of the acceptance tests of a power transformer. These tests have increased importance since the EU Ecodesign Directive per 1 July 2015 has put efficiency limits to power transformers that are sold on the European market. In this paper we present a series of measures to assure that power transformer efficiency tests performed by power transformer manufacturers are accurate and reliable. This includes the development of more accurate industrial loss measure-ment systems (LMS), optimized LMS calibration approaches, and a reference system for on-site LMS calibration.
CIRED - Open Access Proceedings Journal, 2017
As part of the sustainable energy policies of the EU, the Ecodesign Directive puts efficiency req... more As part of the sustainable energy policies of the EU, the Ecodesign Directive puts efficiency requirements per 1 July 2015 on medium and large power transformers. This increases the importance of unambiguous measurement of power transformer losses, and thus of the accuracy of the transformer loss measurement (TLM) systems used by power transformer manufacturers for verification of these losses. Higher accuracy measurements not only lead to increased confidence in the product at the customers, but also allows for saving costs by designing transformers close to the loss limits. To support highquality power transformer loss measurements, VSL has developed a reference system for calibration of TLM systems at the best accuracy levels. A significant advantage is that the TLM systems are calibrated as a whole, thereby covering all possible error sources. Using advanced digital signal processing techniques, high currents are generated with adjustable, stable phase with respect to the applied test voltage. Test results show that calibration accuracies of 25 rad in phase (corresponding to 0.25 % in active power at power factor of 0.01) are achieved for test voltages and currents up to 100 kV and 2 kA respectivelya factor 10 better than typical TLM system specifications.
IEEE Transactions on Instrumentation and Measurement, 2018
An optoelectronic pulse drive system based on commercially available telecoms optoelectronic comp... more An optoelectronic pulse drive system based on commercially available telecoms optoelectronic components and a field-programmable gate array has been developed. In order to allow the use of ac-coupled optoelectronic components, a method of adding and subtracting complementary pulses was developed. The system was used to drive a Josephson junction array to synthesize quantum-accurate voltage waveforms. These waveforms will be used in voltage waveform metrology applications. Results from the synthesis of sinusoidal unipolar voltage waveforms from 3 to 300 kHz are presented. The margin of operation was measured and shown to require an optical pulse height stability better than 0.15 mW. The use of delta-sigma code with repeated sections, suitable for a quantum voltage digitizer was also examined. A test code corresponding to a deltasigma feedback loop rate of 250 MHz was used to synthesize a 3.125 kHz sinusoidal waveform.
Measurement Science and Technology, 2017
A pulse-driven AC Josephson voltage standard (ACJVS) generates calculable AC voltage signals at l... more A pulse-driven AC Josephson voltage standard (ACJVS) generates calculable AC voltage signals at low temperatures, whereas measurements are performed with a device under test (DUT) at room temperature. The voltage leads cause the output voltage to show deviations that scale with the frequency squared. Error correction mechanisms investigated so far allow the ACJVS to be operational for frequencies up to 100 kHz. In this paper, calculations are presented to deal with these errors in terms of reflected waves. Impedance matching at the source side of the system, which is loaded with a high-impedance DUT, is proposed as an accurate method to mitigate these errors for frequencies up to 1 MHz. Simulations show that the influence of non-ideal component characteristics, such as the tolerance of the matching resistor, the capacitance of the load input impedance, losses in the voltage leads, non-homogeneity in the voltage leads, a non-ideal on-chip connection and inductors between Josephson junction array and the voltage leads, can be corrected for using the proposed procedures. The results show that an expanded uncertainty of 12 parts in 10 6 at 1 MHz and 0.5 part in 10 6 at 100 kHz is within reach.
Calibration systems for analogue non-conventional voltage and current transducers
2016 Conference on Precision Electromagnetic Measurements (CPEM 2016), 2016
This paper describes the design and setup of different measuring systems for the calibration of b... more This paper describes the design and setup of different measuring systems for the calibration of both voltage and current transducers which are recently developed at VSL, PTB, and TUBITAK. The output levels of non-conventional transducers are adapted to traditional levels using step-up and step-down converters so that they can be measured using traditional measurement bridges. Verification and performance of a recently developed commercial transformer test set is investigated. The reference measuring systems are developed within the frame of the European project “FUTURE GRID - Non-conventional voltage and current sensors for future power grids”.
Voltage lead errors in an AC Josephson voltage standard: Explanation in terms of standing waves
2016 Conference on Precision Electromagnetic Measurements (CPEM 2016), 2016
A pulse-driven AC Josephson voltage standard generates calculable AC voltage signals at low tempe... more A pulse-driven AC Josephson voltage standard generates calculable AC voltage signals at low temperatures, whereas measurements are performed with a device under test at room temperature. The voltage leads cause the output voltage to show deviations that scale with the frequency squared. So far, these deviations where thought of as a resonance, that could be damped, filtered or corrected for. However, in this paper calculations and measurements are presented that show that the problem is caused by standing waves. Solutions are thought for trying to minimize or compensate the reflection of waves.
Development of a programmable bipolar Josephson-array voltage-standard
Conference on Precision Electromagnetic Measurements. Conference Digest. CPEM 2000 (Cat. No.00CH37031), 2000
We describe the development of a programmable alternating voltage source based on a non-hystereti... more We describe the development of a programmable alternating voltage source based on a non-hysteretic Josephson array. The array is driven by a sinusoidal signal in combination with a digital code. The code causes the array to rapidly switch between states that correspond to its first positive and negative constant-voltage step respectively. If the inverse switching time is made comparable to
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.
Design of a non-invasive current sensor for application on high voltage lines
29th Conference on Precision Electromagnetic Measurements (CPEM 2014), 2014
ABSTRACT This paper describes the design and construction of an openable core current transformer... more ABSTRACT This paper describes the design and construction of an openable core current transformer (CT) to be used on high-voltage lines or busbars. The current sensor consists of a high current stage with a ratio of 400:1 and a low current stage with a ratio of 100:1. Both have a toroid core and are of the enhanced core type. The high current stage is cut in two halves to be able to connect without breaking the high voltage line. The overall accuracy is limited by the cut core of the high current stage. The accuracy is < 10 µA/A and < 5 µrad.
Calibrating a sampling voltmeter using a binary Josephson system
2008 Conference on Precision Electromagnetic Measurements Digest, 2008
Page 1. CALIBRATING A SAMPLING VOLTMETER USING A BINARY JOSEPHSON SYSTEM Helko E. van den Brom, E... more Page 1. CALIBRATING A SAMPLING VOLTMETER USING A BINARY JOSEPHSON SYSTEM Helko E. van den Brom, Ernest Houtzager, Quincy EVN Martina, and Gert Rietveld ... Note that small glitches can occur in between two voltage steps. ...
Minimizing voltage lead corrections for a pulse-driven josephson voltage standard
CPEM 2010, 2010
ABSTRACT This paper describes possible strategies towards minimizing or compensating the influenc... more ABSTRACT This paper describes possible strategies towards minimizing or compensating the influence of the voltage leads when using a pulse driven AC Josephson voltage standard as a calculable reference source in practice.
Selection and characterization of resistors for a HVDC reference divider
2012 Conference on Precision electromagnetic Measurements, 2012
ABSTRACT This paper describes the selection and characterization of resistors for a 1000 kV HVDC ... more ABSTRACT This paper describes the selection and characterization of resistors for a 1000 kV HVDC divider. One thousand 10 MΩ resistors will be connected in series in the final design. Due to the large number of resistors only a randomly selected set has been characterized. The measured temperature and voltage coefficients of the resistors are around 1 μΩ/Ω/K and -10 μΩ/Ω/kV respectively, which make them very suitable for reaching the overall desired divider uncertainty of better than 100 μV/V.
Pulse Drive Electronics for Josephson Arbitrary Waveform Synthesis
2004 Conference on Precision Electromagnetic Measurements, 2004
Two sets of dedicated electronics for driving Josephson arbitrary waveform synthesizers (JAWS) ha... more Two sets of dedicated electronics for driving Josephson arbitrary waveform synthesizers (JAWS) have been manufactured as part of a European collaboration. Their different architectures are described in detail. The results from the characterisation of their electrical outputs are also presented
Characteristics of binary Josephson arrays for a programmable voltage standard
Conference Digest Conference on Precision Electromagnetic Measurements
Within the Euromet project no. 626, I-V curves of two non-hysteretic Josephson arrays (of SINIS a... more Within the Euromet project no. 626, I-V curves of two non-hysteretic Josephson arrays (of SINIS and externally shunted SIS types) are studied at NMi as a function of microwave power at the drive frequency of 76.275 GHz and temperature 4 K. A stable operation at about 1.1 V is registered.
Design of a wideband HVDC reference divider
2012 Conference on Precision electromagnetic Measurements, 2012
ABSTRACT This paper describes design principles of a wideband HVDC reference divider. The modular... more ABSTRACT This paper describes design principles of a wideband HVDC reference divider. The modular divider will be used for traceable calibration of HVDC measuring systems up to 1000 kV in customers' laboratories. The first priority in the design was the accuracy of HVDC measurements. In addition the divider was designed to have wide bandwidth, both to enable measurement of ripple voltages and to prevent damage during possible flashovers.
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
Synthesis of sinusoidal signals with a Josephson arbitrary waveform synthesizer
Superconductor Science and Technology, 2007
... Helko E van den Brom1,4, Ernest Houtzager1, Oleg Chevtchenko1, Gerd Wende2, Marco Schubert2, ... more ... Helko E van den Brom1,4, Ernest Houtzager1, Oleg Chevtchenko1, Gerd Wende2, Marco Schubert2, Torsten May2, Hans-Georg Meyer2, Oliver Kieler3 ... 54 62831 [8] Williams JM, Janssen TJBM, Palafox L, Humphreys DA, Behr R, Kohlmann J and Müller F 2004 Simulation ...
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Papers by Ernest Houtzager