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  • 1. Bastos, M. C.
    et al.
    Hammarquist, M.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    A high-voltage reference testbed for the evaluation of high-voltage dividers for pulsed applications2010Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2010, s. 667-668Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The design, evaluation and commissioning of a high voltage reference testbed for pulsed applications to be used in the precision testing of high voltage dividers is described. The testbed is composed of a pulsed power supply, a reference divider based on compressed gas capacitor technology and an acquisition system which makes use of the fast measurement capabilities of the HP 3458 DVM. Results of the evaluation of the reference system are presented. © 2010 IEEE.

  • 2. Bastos, M. C.
    et al.
    Hammarquist, M.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    A high-voltage test bed for the evaluation of high-voltage dividers for pulsed applications2011Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 60, nr 7, s. 2462-2468, artikkel-id 5682402Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The design, evaluation, and commissioning of a high-voltage reference test bed for pulsed applications to be used in the precision testing of high-voltage dividers is described. The test bed is composed of a pulsed power supply, a reference divider based on compressed-gas capacitor technology, and an acquisition system that makes use of the fast measurement capabilities of the HP3458 digital voltmeter. The results of the evaluation of the reference system are presented. © 2006 IEEE.

  • 3.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Absolute calibration of a 100 KV DC divider1996Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An absolute determination of the ratio of a 100 kV DC divider has been made. A new Zener device that has recently become available has been used in a step-up mode to obtain the divider ratio. The uncertainty of the determination is 5.5 ppm.

  • 4.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Absolute calibration of a 100 kV DC divider.1996Rapport (Fagfellevurdert)
  • 5.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Achievable Accuracy in Industrial Measurement of Dissipation Factor of Power Capacitors2018Inngår i: NCSLI Measure, ISSN 1931-5775, Vol. 12, nr 1, s. 34-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modern dielectrics used in power capacitors can exhibit a dissipation factor lower than 0.005 %, which approaches the limits of presently available measurement techniques. This article reviews techniques, apparatus, and available calibration services for dissipation factor with regard to lowest achievable uncertainties. It is shown that further metrological advances are necessary to lower uncertainty in the measurement to levels at least five times less than presently achievable, in order to ensure traceable and quality-assured measurement of modern dielectrics with such low dissipation factors

  • 6.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Analysis of metrological requirements for electrical measurement of HVDC station losses2012Inngår i: IEEE Transactions on Instrumentation and Measurement, Vol. 61, nr 10, s. 2695-2700Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    23 May 2012

  • 7.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Calibration of high resolution digital recorders for impulse measurements.1998Rapport (Fagfellevurdert)
  • 8.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Difference amplifier for use in accurate voltage transformer calibrations.1989Rapport (Fagfellevurdert)
  • 9.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Estimation of errors of voltage transformers on-site and the uncertainty of the estimate2000Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2000, s. 415-416Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A deregulated energy market needs demonstrably correct energy measurements for correct billing. Voltage transformers may be prone to drift implying a need for verification of their errors. A method to do this on-site using previous calibrations and comparative measurements has been developed and its uncertainty has been estimated.

  • 10.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Influence of coaxial cable on response of high-voltage resisitive dividers2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lightning impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. During these investigations a deterioration of step response was identified when longer coaxial cables were inserted in the measuring circuit. The measured front time T1 was also affected, in one observed case by 2.5 % elongation of front time as another 25 m cable was inserted. Compared to the intention to calibrate front time measurement to better than 5 % uncertainty for front time, this contribution must be well known, or preferably be eliminated. This paper presents the experimental findings from these investigations. The investigated cables included selected coaxial, tri-axial, and cables with a corrugated screen. The effect of cable length was also studied. The influence was first discovered when applying a very fast step (rise-time < 4 ns) to the high voltage arm of a resistive divider and convolution of this step with the time derivative of an ideal lightning impulse with 0.84/60 µs impulse. The calculated output was analysed with IEC 61083 compliant software to evaluate the front time. Subsequently, these analyses have been augmented by additional comparative measurements where two reference dividers were connected to the same impulse generator, and varying the cable length of one of them. The summarized changes in front time calculated for different combinations of cable and impulse voltage dividers are shown and discussed. It is noted that a change in T1 error depends both on length of cable and its type. The results show that non-negligible front time errors may be introduced when the cable length is increased. To support these findings, further tests have been carried out with two reference impulse dividers connected in standard calibration configuration in accordance with IEC 60060-2. One divider was used as reference, while the cable for the other was varied. In this way, the change of error between configurations could be measured. A theoretical study has also been performed, calculating the distortion of a lightning impulse on a coaxial cable. The results agree qualitatively with experiments, but the detailed results show discrepancies that need further investigation.

  • 11.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    In-situ calibration of voltage transformers on the Swedish national grid1996Inngår i: IEE Conference Publication, 1996, nr 426, s. 227-239Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Swedish voltage transformer calibration system is based on the use of a very accurate multi-ratio inductive voltage transformer rated for the full dielectric requirements on the 400 kV grid. The output voltage from the voltage transformer under test is compared to the output from the reference transformer in an automatic bridge circuit. A computer is used to read the data from the bridge and to prepare the calibration certificate. A six decade precision inductive voltage transformer, an inductive voltage divider, can be employed as a ratio matching element.

  • 12.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    International comparison of measurement of 200 kV DC, Results obtained of SP.2008Rapport (Fagfellevurdert)
  • 13.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Measuring system for in-situ calibration of high voltage transformers1994Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 1994, s. 301-302Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A mobile calibration system for in-situ calibration of voltage transformers is analyzed with respect to measuring uncertainty under field conditions. The total basic uncertainty is better than ±0.015% respectively ±0.3 mrad. The system has been, used to calibrate 570 capacitor voltage transformers.

  • 14.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Metrology for high voltage direct current state-of-art and current development2011Inngår i: Joint IMEKO TC11-TC19-TC20 Int. Symp. Metrological Infrastructure, Environmental and Energy Measurement and Int. Symp. of Energy Agencies of Mediterranean Countries, IMEKO-MI 2011, 2011, s. 29-33Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Energy transmission by high voltage direct current - HVDC - is steadily increasing in the world, both at the highest power levels, but also at medium power, for example in connections of remote wind-parks to the main a.c. grid. Although principles for d.c. side measurements are known since long, support from metrology is not on par with the needs. An overview of available technologies and the challenges for metrology shows that advances are needed in determination of power losses in convertors, traceability for transmission line voltage measurement, power quality and d.c. side metering. Response to these challenges is given by seven national metrology institutes, one university and one industrial partner, in a project funded by the European Union under Article 169. The research will provide traceable calibrations and measurements in the assigned areas, and capability of measurement will extend to transmission line levels including 1000 kV d.c.

  • 15.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Publishable JRP2012Rapport (Fagfellevurdert)
  • 16.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Qualification of a reference measuring systems for impulse voltage.1992Rapport (Fagfellevurdert)
  • 17.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Elektronik.
    Bergman, Allan
    RISE - Research Institutes of Sweden.
    Jönsson, Bengt
    ABB AB, Sweden.
    Rietveld, Gert
    VSL Nederlands Metrologisch Instituut, Netherlands.
    Sauzay, Mathieu
    JST transformateurs, France.
    Walmsley, Jonathan
    GE Power, UK.
    Sund, John Bjarne
    MSC EE Transformer Consultant, Norway.
    Estimating Uncertainty in Loss Measurement of Power Transformers2019Inngår i: ISH 2019, International Sympsoium on High Voltage Engineering, Budapest, Hungary, August 26-30, 2019., 2019Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Eco-design directive issued by the European Commission has led to re-quirements on efficiency of power transformers. In the case of large power transformers used in grid applications, serious problems are encountered in establishing how reliable the loss measurements are. An effort is currently on-going within IEC to produce a documentary standard on “Rules for the determination of uncertainties in the measurement of the losses of power transformers”. An IEC standard should be clear and easy to understand by all users in the industry. Background theory and material, whilst necessary for understanding, is not required for the day-to-day application of the standard. This paper presents a more detailed background and theory on the measure-ment of transformer losses and how to quantify precision. The authors are all members of the IEC maintenance team working with the standard.

  • 18.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergman, Sixten
    Consultant, Rönnvägen 1 A, 507 71 Gånghester, Sweden.
    Hoffmann, Christian
    Baur Gmbh, Austria.
    Paulus, Eberhard
    Baur Gmbh, Austria.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Traceable measurement of dielectric dissipation factor at Very Low Frequency2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Very Low Frequency (VLF) tests are often used for after-laying tests of power cables since the reactive power demand is much lower at VLF than at 50 Hz. In order to augment the usefulness of the test, it is often complemented by a measurement of dielectric dissipation factor (tan ), where the acceptance of the tested object is based on this measurement. A traceability chain for dissipation factor at high voltage and very low frequency has as yet not been recognized by the International Bureau of Weights and Measures (BIPM), which results in difficulties to prove the quality of the measurement. The measurement is complicated by the limited range of the current in the test object that can be resolved by available high voltage test equipment, thus limiting the possible choices of reference systems. A novel reference measuring system that can fulfil these needs has been developed at SP Technical Research Institute of Sweden in the capacity as National Measurement Institute. The traceability of the system to National Standards of Measurement is ensured by careful scientific work and analyses. This measuring system has the ability to measure dissipation factor at 0.1 Hz in the voltage range from 0.5 kV up to 50 kV with an uncertainty better than 0.004 %.

  • 19.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Elg, Alf Peter
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Hällström, J
    Dedeoglu, S
    Houtzager, E
    lucas, W
    Merev, A
    Weber, C
    Design of a wideband HVDC reference divider2012Inngår i: Conference on Precision Electromagnetic Measurements, CPEM 2012, 2012, , s. 207-208s. 207-208Konferansepaper (Fagfellevurdert)
  • 20.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hällström, Jari
    VTT-MIKES, Finland.
    Evaluation of step response of transient recorders for lightning impulse2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    High voltage equipment will be subjected to several types of electrical stress during operation. A battery of factory tests is defined to ensure that the equipment will perform satisfactorily in service. One of the crucial tests is to apply a simulated lighting impulse as standardised to a double-exponential impulse with at front time of 1.2 µs (± 30 %) and a time to half value of 50 µs (± 20 %). Although this wave-shape only approximates natural lightning, there is a solid body of experience within industry, proving that reliability of equipment in service is adequately proven by the standard waveform. It is however crucial for consistency of results that the both voltage level and wave-shape are correctly measured. This paper discusses the requirements and performance of the recording instruments used, leaving the properties of high voltage impulse dividers outside the discussion. The requirements for the recording instrument – transient recorder – are given in IEC 61083-1. The standard provides requirements for, and/or tests to verify, that the recorder has moderately fast response, fast settling time, high resolution, linearity under dynamic conditions, high accuracy and reasonably low internal noise. This is partly in contrast to major trends in transient recorder development, where fast sampling and fast step response are prioritized ahead of high accuracy and fast settling without creeping response. We have therefore evaluated several commercially available recorders in order to find one with respectively flat and reasonably fast step response. In this campaign, a proprietary step generator based on the use of a mercury reed relay has been used. Evaluation of this device is submitted to ISH 2017. It has been found that the measured flatness of the step response directly after the step is a good first indicator of the performance of the transient recorder. This is identified in IEC 61083-1 clauses 1.5.2 and 1.5.3, as a requirement on stability of the recorded step from 0.5 T1min to T2max. For lightning impulse this means from 0.42 µs to 60 µs. For approved transient recorders the requirement is to be within 1 %. For reference transient recorders, a limit of not more than 0.5 % should be applied. Further proof of the accuracy of the transient recorder can be achieved by convolution of an ideal waveform with the recorded step response and analysing the resulting curve with lightning impulse parameter software. A third possibility is to make direct calibration of the transient recorder, using a calculable impulse calibrator. Several state-of-art transient recorders have been evaluated and the results show that only a few are suited for measurement of lightning impulse. Also, the variation of the performance between the ranges and channels of one instruments are significantly large. Both direct assessment of step response as well as result of convolution with a theoretical 0.84/50 µs impulse will be reported. The agreement with results obtained with a calculable impulse calibrator will be illustrated.

  • 21.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Hällström, J
    Impulse dividers for dummies2003Konferansepaper (Annet vitenskapelig)
  • 22.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik.
    Larsson, A
    Verfication of AC measuring system linearity1998Inngår i: Conference proceedings, ERA Technology, 1998, , s. 2/2.1-10Konferansepaper (Annet vitenskapelig)
  • 23.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Marx, R.
    Schon, K.
    Suomalainen, E. -P
    Hallstrom, J.
    Intercomparison of AC peak voltage measurement1999Inngår i: IEE Conference Publication, 1999, nr 467, s. 1.9.S1-1.12.S1Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An intercomparison on the measurement of high voltage peak value has been carried out between the National Metrology Institutes of Sweden and Germany in 1995 and between Finland and Sweden in 1996. The results show a very satisfactory agreement between the participants. It seems that part of the discrepancies found may be due to the loose definition of peak voltage in IEC 60060-1.

  • 24.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Meisner, J
    Svensson, Stefan
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Enabling DC-Side Metering in HVDC Stations2014Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 29, nr 1, s. 370-377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    HVDC power transmission is now being considered not only for point-to-point interties, but also as true grids where several operators may tie into the grid, each having its own economic sphere. In this new situation, it is important that transmitted energy be distinguished from losses incurred in the converter stations, to enable a fair distribution of costs for grid operation. To this end, a metrology infrastructure is needed where high-current and high-voltage transducers must be possible to calibrate traceably, and where dc electricity meters can be calibrated and approved. A research project is currently working with these questions in a concerted European research effort, funded by the European Commission. The present publication highlights important aspects of this work.

  • 25.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Nilsson, H.
    A Constant Voltage Source Based on a Mercury Battery1993Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 42, nr 2, s. 365-367Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A constant voltage source based on a stable mercury battery has been developed at SP (Swedish National Testing and Research Institute). By using as active current compensation technique, the inherent high stability of a mercury battery can be retained up to a load current of several milliamperes.

  • 26.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Characterisationat low voltage of two reference lightning impulse dividers2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An effort is pursued by several European National Measurement Institutes to lower the uncertainties in calibration of UHV measuring systems for lighting impulse. To this end, several reference dividers are investigated as regards their accuracy both for amplitude and for time parameters. At SP - RISE Research Institutes of Sweden, a 500 kV resistive reference divider has been in use since 2000. Additionally an 800 kV resistive divider is investigated as a possible reference divider for UHV lightning impulse measuring systems. The best uncertainty for the 500 kV reference measuring system is 1 % for voltage amplitude and 3 % for time parameters. The present work aims at lowering these uncertainties by means of better characterisation and evaluation of the possibilities to apply corrections for known errors. The scale factor and dynamic behaviour of a resistive divider can be conveniently determined at low voltage and frequency. Further experiments such as linearity tests and augmented by scientific work is needed to ascertain the performance at high voltage. Step response plays a major role in the characterisation of dividers, and in this work much effort has gone into gathering step responses and evaluating them for various circuit layouts to characterise the variation of the step response due to circuit dimensions and diverse proximity effects. The step applied to the divider is generated by a mercury wetted relay based step generator with an output voltage of 200 V. The step rise-time is a few ns, and thus appreciably faster than the response of the divider. Apart from inspection of the step response itself, evaluation of measurement errors is performed by convolving an ideal curve with the step response of the divider, including its transmission cable. The convolved signal is evaluated with impulse evaluation software and the parameters compared to the ideal input. The difference is a measure of the errors introduced by the divider. This procedure follows IEC 60060-2: 2010.

  • 27.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Nordlund, Mathias
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Meisner, Johann
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Passon, Stephan
    Physikalisch-Technische Bundesanstalt PTB, Germany.
    Hällström, Jari
    VTT-MIKES, Finland.
    Lehtonen, Tapio
    VTT-MIKES, Finland.
    Characterization of a fast step generator2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lighting impulse measurements are made as a matter of routine in high voltage testing of high-voltage electrical equipment. The test is often decisive for acceptance of the equipment under test, and consequently proper and precise calibration of the measuring system is needed. The present work centres on the need to quantify the errors of reference measuring systems for lightning impulse. Scale factor determination at low frequency (or DC) is the starting point for this determination. The extrapolation from this frequency domain to the domain where microsecond pulses must be faithfully captured requires application either of methods in the frequency domain or in the time domain. Radio frequency measurements are only well defined for coaxial structures and at impedances in the range of 50 O or thereabouts, making them difficult to apply to the large structures of high-voltage measuring systems. The converse method in the time domain is to apply a Dirac impulse to the system and calculate the response to an assumed input signal by convolution. A true Dirac pulse is not readily available and in practice the applied pulse is a step voltage, which is then derived with respect to time and convolved with the applied signal to obtain the response of the measuring system. The step generator used for this purpose should have very fast front without oscillations. The intent is to achieve a close approximation of an ideal step function, which when derived with respect to time, yields the impulse response of a tested system. A necessary prerequisite is that the step is much steeper than the lightning impulse, and is flat after the step on times much longer than the impulse. The ideal switch element in such a step generator should have infinite resistance and zero capacitance in the off-state, very fast switching to on-state and very low resistance in on-state. The mercury wetted reed switch has often been used for this purpose since it has good characteristics in all these respects. Few, if any, electronic components exhibit competitive advantages compared to the reed switch. The relative lack of parasitic effects means that it is close to being an ideal device. Based on earlier experiences by the authors, a new design has been developed with focus on electrical screening and coaxial design in order to realise a step generator that works into a high impedance instrument. Considerable work has been performed to characterise the new device with regard to steepness of step and most importantly, to voltage stability after the step. The most demanding part of this work has been to separate the performance of the switch from that of the oscilloscope. Findings indicate that the step rise-time is less than 0.5 ns, and settling to within 0.5 % within 10 ns.

  • 28.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Pogliano, U.
    Hällström, J.
    Wright, P.
    Lucas, W.
    Merev, A.
    Rietveld, G.
    Kurrat, M.
    Rickmann, J.
    Metrology for high voltage direct current2010Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2010, s. 669-670Konferansepaper (Fagfellevurdert)
    Abstract [en]

    HVDC energy transmission is crucial for a successful uptake of renewable energy sources in the grid. A research program is described, intended to provide metrology support for the needs of HVDC energy transmission. This program will provide improvements for the present HVDC metrology infrastructure: accurate measurement of HVDC, determination of losses in HVDC systems, on-site power quality measurements at HVDC substations, and DC metering. It is a combined effort of 7 European national metrology institutes, one university and one industrial partner. © 2010 IEEE.

  • 29.
    Bergman, Anders
    et al.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Rietveld, Gert
    VSL, Netherlands.
    CIGRE Science & Enginering, Volume No.15, October 2019: Innovation in the Power Systems industry2019Inngår i: CIGRE Science & Engineering, ISSN 2426-1335, Vol. 15, s. 85-93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Losses of HVDC converter stations need to be accurately quantified to support evaluation of bids for such systems and to underpin efforts to reduce greenhouse gas emissions. At present, these losses are estimated, based on loss calculations for individual converter components, and no reliable method exists to measure the actual HVDC converter station loss as difference between power on the AC- and DC-side of the station. The necessary requirements for such a measurement are investigated in this study, and a tentative design of a suitable loss measuring setup is explored. This approach is a useful alternative for those cases where a direct measurement of losses via a temporary connection with two converters operating in back-to-back mode cannot be made.

  • 30.
    Bergman, Anders
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Wang, Feng
    Le Tuan, Ahn
    Bertling-Tjernberg, Lina
    A New Approach for Benefit Evaluation of Multiterminal VSC-HVDC Using A Proposed Mixed AC/DC Optimal Power Flow2013Inngår i: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 99Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, an extended optimal power-flow (OPF) model incorporating a detailed model of a voltage-source converter-based–multiterminal high-voltage direct current system (VSC–MTDC) is proposed, hereafter referred to as the mixed ac/dc OPF (M-OPF) model. A cost-benefit analysis approach using the M-OPF model as the calculation engine is proposed to determine the preferred VSC-MTDC alternative to be installed in an existing ac transmission system. In this approach, the operational benefits of VSC–MTDC systems are evaluated against their investment costs to derive the benefit-to-cost ratios (BCR) which reflect the cost-effectiveness of the alternatives. A case study has been carried out using a modified Nordic 32-bus system. The results of the study show that VSC–MTDC systems might lead to a reduction in total operation cost, and the reduction of the total system transmission loss depends to a large extent on the VSC–MTDC configuration. The results from sensitivity analyses show that if the VSC loss could be reduced to a third of the original level, the total benefit from the system would be increased by about 70%. A suggestion for the placement and configuration of a VSC–MTDC system is made based on calculated BCRs.

  • 31.
    Bergman, Sixten
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    New reference measurement system for calibration of VLF high voltage2010Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2010, s. 682-683Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A reference measuring system for 200 kV at very low frequency (0.1 Hz, VLF) has been developed and verified. The reference system will make it possible to perform traceable calibration of VLF test systems used for after-laying-tests of extruded power cables. © 2010 IEEE.

  • 32.
    Bergman, Sixten
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    New reference measurement system for calibration of VLF high voltage2011Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 60, nr 7, s. 2422-2426, artikkel-id 5746641Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A reference measuring system for 200 kV from very low frequencies (0.1 Hz, VLF) up to 50 Hz based on traditional high-voltage components, such as compressed gas capacitors, has been developed and verified. The verification of the measuring system has been performed by two experimental methods, one directly measuring the scale factor and one using measurements over the frequency and voltage range of the components of the measuring system. The frequency dependence of the measuring system proved to be one of the dominating uncertainties and was extensively researched. Proper correction for known errors and estimation of uncertainty contributions proved that traceable measurement of VLF voltage can be made with an uncertainty of less than 0.038% up to a voltage of 200 kV. This measurement service has been notified to be included in SP entries for Bureau International des Poids et Mesures key comparison database and can serve an important need for the cable industry. © 2006 IEEE.

  • 33. Cerqueira Bastos, Miguel
    et al.
    Hammarquist, Maria
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    A High-Voltage Testbed for the Evaluation of High-Voltage Dividers for Pulsed Applications.2011Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 60, nr 7, s. 2462-2468Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The design, evaluation and commissioning of a high voltage reference testbed for pulsed applications to be used in the precision testing of high voltage dividers is described. The testbed is composed of a pulsed power supply, a reference divider based on compressed gas capacitor technology and an acquisition system which makes use of the fast measurement capabilities of the HP 3458 DVM. Results of the evaluation of the reference system are presented.

  • 34.
    Draxler, K.
    et al.
    CTU, Czech Republic.
    Styblikova, R.
    CMI, Czech Republic.
    Hlavacek, J.
    CTU, Czech Republic.
    Rietveld, G.
    VSL, Netherlands.
    Van Den Brom, H. E.
    VSL, Netherlands.
    Schnaitt, M.
    BEV, Austria.
    Waldmann, W.
    BEV, Austria.
    Dimitrov, E.
    BIM, Bulgaria.
    Cincar-Vujovic, T.
    DMDM, Serbia.
    Paczek, B.
    GUM, Poland.
    Sadkowski, G.
    GUM, Poland.
    Crotti, G.
    INRIM, Italy.
    Martin, R.
    LCOE, Spain.
    Garnacho, F.
    LCOE, Spain.
    Blanc, I.
    LNE, France.
    Kampfer, R.
    METAS, Switzerland.
    Mester, C.
    METAS, Switzerland.
    Wheaton, A.
    NPL, UK.
    Mohns, E.
    PTB, Germany.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Hammarquist, Maria
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Cayci, H.
    UME, Turkey.
    Hallstrom, J.
    VTT, Finland.
    Suomalainen, E. -P
    VTT, Finland.
    Results of an International Comparison of Instrument Current Transformers up to 10 kA at 50 Hz Frequency2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    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. .

  • 35.
    Elg, Alf Peter
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Hallstrom, J.
    Kharezy, M.
    Nieminen, T.
    Traceability and characterization of a 1000 kV HVDC reference divider2014Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2014, s. 780-781Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents the characterization of a resistive HVDC reference divider and methods to establish a traceability. The divider is designed for use as a laboratory reference for calibration of HVDC measuring systems up to 1000 kV. Targeting a measurement uncertainty of 20 ppm at full voltage has put a focus on the temperature coefficients of the resistors, elimination of humidity dependence and control of leakage currents in the high voltage arm. © 2014 IEEE.

  • 36.
    Elg, Alf Peter
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Hällström, Jari
    MIKES Centre for Metrology and Accreditation, Finland.
    Kharezy, Mohammad
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Nieminen, Tatu
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Traceability and Characterization of a 1000 kV HVDC Reference Divider2015Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 64, nr 6, s. 1709-1715, artikkel-id 7100891Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents the characterization of a resistive high-voltage dc (HVDC) reference divider and methods to establish traceability. The divider is designed for use as a laboratory reference for calibration of HVDC measuring systems up to 1000 kV. Targeting a measurement uncertainty of 20 μV/V at full voltage has put a focus on the temperature coefficients of the resistors, elimination of humidity dependence, and control of leakage currents in the high-voltage arm. A scale factor calibration against a 50 kV divider at 10 kV leads to an expanded uncertainty of 15 μV/V.

  • 37.
    Elg, Alf Peter
    et al.
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Kharezy, M.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Hällström, J.
    Characterization of dielectric properties of insulating materials for use in an HVDC reference divider2012Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2012, s. 80-81Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Dielectric properties of polyethylene (PE), polyoxymethylene (POM) and ceramic glass (MACOR) are compared. Their suitability to act as a support for a resistor chain in a wideband HVDC reference divider is characterized. The support material forms a parallel capacitance to the resistive resistor chain, and a bandwidth of more than 100 kHz is needed. The frequency dependence of dielectric constant has been measured in the range 20 - 100 kHz. The depolarization current of these materials was measured to be at least 6 orders of magnitude lower than the current through the resistive chain. Neither MACOR nor PE does build up space charge which POM does. Possessing the highest dielectric constant makes MACOR well suited for the application. © 2012 IEEE.

  • 38. Feng, W.
    et al.
    Tjernberg, L. B.
    Tuan, L. A.
    Mannikoff, A.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    An extended OPF incorporating multi-terminal VSC-HVDC and its application on transmission loss evaluation2013Inngår i: 2013 IEEE Grenoble Conference PowerTech, POWERTECH 2013, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper proposes an extension of the traditional ac Optimal Power Flow (OPF) model to incorporate the Voltage Source Converter based Multi-terminal High Voltage Direct Current system (VSC-MTDC). In the extended OPF model, the detailed VSC-MTDC system model is included, and the key technical limits of VSC (e.g., the maximum VSC valve current and the maximum dc voltage) are used as the operating constraints of the VSC-MTDC system. The extended OPF model is applied to a case study using the Nordic 32-bus system to evaluate the contribution of the embedded VSC-MTDC system on the overall system loss reduction. The study results show that the overall system loss of an ac transmission grid is not necessarily reduced by embedding a VSC-MTDC system into it. The reduction of the system loss by embedded VSC-MTDC system depends on their configuration and location, and the VSC station loss ratio as well. © 2013 IEEE.

  • 39. Gunnarsson, O.
    et al.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Rydler, K. -E
    A method for calibration of partial discharge calibrators1999Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 48, nr 2, s. 453-456Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method for calibration of partial discharge calibrators has been developed based on passive integration of the induced charge. The voltage over a known capacitor is measured by a calibrated digital sampling voltmeter and the charge is calculated as the voltage multiplied by the capacitance. The best achieved uncertainty is ±2% with a coverage factor k = 2. © 1999 IEEE.

  • 40. Gunnarsson, O.
    et al.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Rydler, K. -E
    Method for calibration of partial discharge calibrators1998Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 1998, s. 205-206Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A method for calibration of partial discharge calibrators has been developed based on passive integration of the induced charge. The voltage over a known capacitor is measured by a calibrated digital sampling voltmeter and the charge is calculated as the voltage multiplied by the capacitance. The best achieved uncertainty is ±2% for a coverage factor k = 2.

  • 41. Hallstrom, J.
    et al.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Dedeoglu, S.
    Elg, Alf Peter
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Houtzager, E.
    Lehtonen, T.
    Kluss, J.
    Lucas, W.
    Merev, A.
    Nieminen, T.
    Meisner, J.
    Suomalainen, E. -P
    Schmidt, M.
    Weber, C.
    Performance of a modular wideband 1000 kV HVDC reference divider2014Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2014, s. 782-783Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes the performance of a wideband HVDC reference divider. The divider concept is a shielded modular divider and it is intended 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. © 2014 IEEE.

  • 42. Hallström, J.
    et al.
    Aro, M.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Bovier-Lapierre, V.
    Garnacho, F.
    Juvik, J. I.
    Kiseliev, V.
    Lian Hong, Z.
    Lucas, W.
    Li, Y.
    Pykälä, M. -L
    Rungis, J.
    Schon, K.
    Truong, V. H.
    Worldwide comparison of lightning impulse voltage measuring systems at the 400-kV level2007Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 56, nr 2, s. 388-391Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An international comparison of lightning and switching impulse voltage measuring systems was arranged and coordinated by the Helsinki University of Technology (MIKES-TKK), Espoo, Finland, between 1999 and 2002. The number of participants was 26, including the coordinator. This paper summarizes the results obtained by those eight National Metrology Institutes that participated in the comparison. A 400-kV transfer reference measuring system for measuring lightning impulse voltages was prepared by the coordinator. In addition, a 1-kV impulse voltage calibrator system, including calibrators for both standard lightning and switching impulses, was circulated. © 2007 IEEE.

  • 43. Hammarqvist, M.
    et al.
    Elg, Alf Peter
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Wolbert, J.
    Blennow, J.
    Gubanski, S. M.
    Improvement of frequency response for a zero-flux current measuring system2014Inngår i: CPEM Digest (Conference on Precision Electromagnetic Measurements), 2014, s. 618-619Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Magnetic zero-flux current transformers are widely utilized to measure AC and DC electrical currents. To improve the AC characteristics between 10 Hz and 100 kHz, a method is proposed to evaluate adjustments in the circuitry; increase of the amplification in the AC feed-back circuit and introduction of an external coaxial read-out shunt resistor. The method is generally applicable and includes a coaxial current path within the entire reference system and traceability to national standards. The AC working range is extended from about 1 kHz to about 3 kHz. Outside the nominal AC working range, the scale factor variation is reduced from 45 % to 3.5% and the phase angle error offset changes from ca 5.8 μs to below 0.3 μs. © 2014 IEEE.

  • 44.
    Havunen, Jussi
    et al.
    VTT-MIKES, Finland.
    Hällström, Jari
    VTT-MIKES, Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergman, Allan E.
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Using deconvolution for correction of non-ideal step response of lightning impulsedigitizers and measurement systems2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Lightning impulse measurements can be highly influenced by measurement arrangement, characteristics of high voltage divider, digitizer (transient recorder) performance, and algorithms used for parameter evaluation. The main sources of measurement errors are the non-ideal step responses of digitizer and voltage divider. This paper discusses the use of deconvolution to correct for the non-ideal step response of a digitizer, and of a large mixed divider. Correcting the step response of the complete measuring system by one part at a time is desirable because it allows to evaluate the effectiveness of the correction with trustworthy methods. Step response describes the output of a system as function of time when its input changes between two levels infinitely fast. Real life impulse digitizers and impulse voltage dividers have a finite rise time, and the response does not immediately settle to final value. Slow rise time is often the cause of error for front time parameter. Creeping response is often the cause of error for time to half-value parameter. Step response of an instrument can be determined by applying a stable, known direct voltage, which is then shorted to ground by a mercury-wetted relay. The mercury-wetted relay is assumed nearly an ideal switch, which creates almost an ideal voltage step for input of the instrument. Convolving the derivative of the measured step response with an ideal input gives a measure of distortion caused by the non-perfect step response, and conversely deconvolving the measured step response with the measured signal gives the original input signal. This paper presents an FFT-based method for step response correction using deconvolution. Deconvolution is a mathematical process, which is used to reverse the non-ideal effects of measuring instrument on recorded data. Effectiveness of the method is demonstrated by two examples. In the first example, the non-ideal step responses of the different ranges of an impulse digitizer are corrected. Functionality of the step response correction is evaluated by comparing the results against a calculable impulse voltage calibrator. Results showed that the step response correction reduced errors in lightning impulse parameters. Stability of the step response correction was analysed by studying several impulse calibration results that have been performed for the instrument within a year. The second example corrects the response of a 2400 kV impulse voltage divider. The effectiveness of the correction is evaluated by comparing its results to a 400 kV reference divider.

  • 45.
    Havunen, Jussi
    et al.
    VTT, Finland.
    Passon, Stephan
    PTB, Germany.
    Hallstrom, Jari
    VTT, Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Effect of Coaxial Cables on Measurements Performed with Resistive Lightning Impulse Voltage Dividers2018Inngår i: CPEM 2018 - Conference on Precision Electromagnetic Measurements, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The effect of the coaxial cable type and length on the lightning impulse parameters is often neglected. However, studies have shown that the coaxial cable length can affect the parameters that are calculated according to IEC 60060-1:2010. This study investigates how different coaxial cables influence the impulse waveforms by measuring the input and output of the cable under test with a 2-channel digitizer. Non-standard lightning impulses were generated using an impulse voltage calibrator. Results indicate that coaxial cables attenuate the test voltage and increase both the front time and time-to-half value.

  • 46. Hällström, J.
    et al.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Dedeoǧlu, S.
    Elg, Alf Peter
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Houtzager, E.
    Lucas, W.
    Merev, A.
    Meisner, J.
    Schmidt, M.
    Suomalainen, E. -P
    Weber, C.
    Performance of a wideband 200-kV HVDC reference divider module2014Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 63, nr 9, s. 2264-2270, artikkel-id 6754159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes the design and performance of a wideband high-voltage dc (HVDC) reference divider module. The module has a nominal voltage of 200 kV, and it has been designed so that a number of modules can be stacked to extend voltages up to 1000 kV. The module, or a stack of modules, will be used for traceable calibration of HVDC measuring systems 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. 0018-9456 © 2014 IEEE.

  • 47.
    Hällström, J
    et al.
    Helsinki University of Technology (TKK), Finland.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Ding,
    Beijing Hua Tian Mechanical-Electrical Institute (BHT), China.
    Garnacho, F
    Electrotechnical Official Central Laboratory (LCOE), Spain.
    Gobbo, R
    University of Padova, Italy.
    Kato, T
    Doshisha University, Japan.
    Li, Y
    National Measurement Institute (NMIA), Australia.
    Nilsson, Andreas
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Pesavento, G
    University of Padova, Italy.
    Sato, S
    Utsunomiya University, Japan.
    Yu, AX
    Beijing Hua Tian Mechanical-Electrical Institute, China.
    International comparison of software for calculation of lightning impulse parameters based on a new processing algorithm2007Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A new algorithm has been proposed to calculate the parameters of full lightning voltage impulses. The new algorithm enables the application of the test voltage factor (also referred to as k-factor in some literatures) for calculation of the equivalent test voltage of impulses with superimposed oscillations/overshoots. The new algorithm at the same time provides a robust procedure for obtaining time parameters of the impulses from not only smooth waveforms but also waveforms with varying degrees of distortions in the front part of the impulses. These distortions include oscillations on the impulse front and overshoots in the peak region. A critical part of the new algorithm is a 4-parameter fitting procedure to obtain the base curve, which is used for calculation of the test voltage curve. Another important part of the algorithm is applying a filtering procedure in the calculation of the test voltage curve.

     

    The new algorithm was tested in different laboratories using different programming languages and different techniques for realising the fitting and filtering routines. The paper reports the results obtained from the participating laboratories using the proposed algorithm. The results obtained by the participating laboratories using existing software based on the requirement of IEC 60060-1: 1989 were also compared. It is anticipated that the results can serve as a part of the basis for a new procedure for determination of lightning impulse parameters in the revised IEC 60060-1.

  • 48.
    Hällström, Jari
    et al.
    VTT Technical Research Centre of Finland, Finland.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Dedeoğlu, Serkan
    TÜBİTAK UME National Metrology Institute, Turkey.
    Elg, Alf Peter
    RISE., SP – Sveriges Tekniska Forskningsinstitut.
    Houtzager, Ernest
    VSL Dutch Metrology Institute, Netherlands.
    Klüss, Joni
    Aalto University, Finland.
    Lehtonen, Tapio
    VTT Technical Research Centre of Finland, Finland.
    Lucas, Wolfgang
    PTB Physikalisch-Technische Bundesanstalt, Germany.
    Meisner, Johann
    PTB Physikalisch-Technische Bundesanstalt, Germany.
    Merev, Ahmet
    TÜBİTAK UME National Metrology Institute, Turkey.
    Nieminen, Tatu
    Aalto University, Finland.
    Schmidt, Matthias
    PTB Physikalisch-Technische Bundesanstalt, Germany.
    Suomalainen, Esa-Pekka
    VTT Technical Research Centre of Finland, Finland.
    Weber, Christian
    Trench Switzerland and France, France.
    Performance of a Modular Wideband HVDC Reference Divider for Voltages up to 1000 kV2015Inngår i: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 64, nr 6, s. 1390-1397, artikkel-id 7063966Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes the design and performance of a modular wideband high-voltage dc (HVDC) reference divider with a ratio uncertainty of less than 0.005% at 1000 kV. The divider has a maximum nominal voltage of 1000 kV when five 200-kV modules are stacked on top of each other. The divider is used for traceable calibration of HVDC measuring systems 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.

  • 49.
    Larzelere, W
    et al.
    Evergreen HV, USA.
    Hällström, J
    VTT, Finland.
    Elg, Alf Peter
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Bergman, Anders
    RISE - Research Institutes of Sweden, Säkerhet och transport, Mätteknik.
    Kluss, J
    Mississippi State University, USA.
    Li, Y
    National Measurement Institute, Australia.
    Zhou, L
    Hua Gao, China.
    MEASUREMENT OF THE INTERNAL INDUCTANCE OF IMPULSEVOLTAGE GENERATORS AND THE LIMITS OF LI FRONT TIMES2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The recent push to higher testing voltages for research and production tests onUHV system components rated above 800kV class has led to difficulties in achieving thestandard waveshapes as required by IEC60060 Parts 1 and 2 and other existing IEC,IEEE/ANSI and other standards. One of the limiting components in achieving themaximum capacitive loading on an impulse generator for standard lightning impulse fronttimes is the inductance of the circuit. The total inductance of the circuit is comprised ofthe internal inductance of the impulse generator and the inductance of the loop toconnect to the load. The higher the voltage class of test objects, the larger the loop,yielding more inductance that in turn, reduces the test capacitance that can be connectedand still remain inside the overshoot requirements of the standards. The internalinductance of the impulse generator is comprised of the wiring of the stages and thestage capacitor inductance and/or the inductance of the waveshaping resistors. Thispaper shows the results of methods to measure and calculate the internal inductance ofseveral impulse generators and we review the formulas for calculating the maximum loadof an impulse generator with a given internal inductance. We believe these methods givemore realistic values than adding up nameplate inductance values from an impulsegenerator. The paper also reviews the pros and cons of higher stage capacitances inimpulse generators to test larger loads that are ultimately limited by the circuit inductancevalue. The intent of this paper is to assist in the revision of future IEC and IEEE standardsfor impulse testing apparatus in the UHV range

  • 50. Li, Yi
    et al.
    Bergman, Anders
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Larzelere, Bill
    Rickmann, Johannes
    Hauschild, Wolfgang
    Diaz, Ricardo
    Garnacho, Fernando
    McComb, Terry
    Zhang, Y
    Elg, Alf Peter
    RISE., SP – Sveriges Tekniska Forskningsinstitut, SP Mätteknik, Elektricitet.
    Past, present and future of IEC and IEEE high-voltage and high current testing standards2014Rapport (Fagfellevurdert)
    Abstract [en]

    Recently, IEC and IEEE have published a number of revised and new standards for high-voltage and high-current testing. Significant changes and additions have been introduced to these revised and new standards. CIGRE WG D1.35 has developed a guide to give high-voltage test engineers a broader knowledge of how to apply the latest high-voltage and high-current testing standards. The guide presents a brief account of the history of these standards with the aim to allow readers to gain a better appreciation of the technical background followed by sections summarize the major changes made to the standards in their latest revisions to provide a general picture of the revisions. Finally, some discussion is given on the practical implications of these changes. Practical examples are provided to illustrate some of the new techniques and new procedures. The guide also lists areas of possible improvements to the standards for future revisions.

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