| 1. |
- Elg, Alf Peter, et al.
(författare)
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Traceability and characterization of a 1000 kV HVDC reference divider
- 2014
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Ingår i: CPEM Digest (Conference on Precision Electromagnetic Measurements). - 9781479952052 ; , s. 780-781
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Konferensbidrag (refereegranskat)abstract
- 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.
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| 2. |
- Elg, Alf Peter, et al.
(författare)
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Traceability and Characterization of a 1000 kV HVDC Reference Divider
- 2015
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 64:6, s. 1709-1715
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Hällström, Jari, et al.
(författare)
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Performance of a Modular Wideband HVDC Reference Divider for Voltages up to 1000 kV
- 2015
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 64:6, s. 1390-1397
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 4. |
- Kharezy, Mohammad, 1968, et al.
(författare)
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Performance of Insulation of DC/DC Converter Transformer for Offshore Wind Power Applications
- 2020
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Ingår i: Annual Report - Conference on Electrical Insulation and Dielectric Phenomena, CEIDP. - 0084-9162. ; 2020-October, s. 382-385
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Konferensbidrag (refereegranskat)abstract
- High voltage direct current transmission is an effective way of energy transportation from offshore wind farms to the grid. One of the most economical solutions to realize it is based on a series connection of the wind turbines. This technology requires implementation of a DC/DC converter incorporating a special transformer operating at high DC voltages with superimposed high frequency components. To design the high voltage insulation of such a transformer, the dielectric properties of the materials constituting the insulation are to be known in a wide range of variations of the electric field and temperature. In the present study, results of the measurements of field and temperature dependencies of the electric conductivities of a typical high-quality mineral transformer oil and oil-impregnated pressboard are reported. The measurements were performed at different combinations of voltage-temperature stresses reflecting the insulation’s operation condition. The obtained data are used for performance evaluation of the insulation system of a prototype of the transformer.
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| 5. |
- Rydler, Karl-Erik, et al.
(författare)
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A calorimetric measuring system for measurement of loss in high voltage cable conductors
- 2019
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Ingår i: JiCable 2019, 10th international conference on insulated power cables, Versailles,France. June, 2019..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- A calorimetric measuring system for measuring the ratio between AC and DC resistance, RAC/RDC, of high voltage power cable conductors has been designed and constructed. An uncertainty analysis predicts that the ratio RAC/RDC at 90°C of a 2500 mm2 cable of low loss design can be measured with an uncertainty of 1,0%. But the uncertainty of an actual measurement was larger due to unresolved sources of uncertainty.
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