Supplementary comparison for the traceability in high voltage capacitance and dissipation factor measurements (EURAMET.EM-S34)

Abstract

Main textThe intercomparison consisted of calibrating the capacitance and loss factor (tan δ) of a set of reference capacitors at different voltage levels, including high voltage up to 200 kV, for frequencies between 50 Hz and 1kHz in low voltage measurements and 50 Hz in high voltage measurements.The travelling standards consisted of a set of four reference capacitors (TRC) with fixed input and grounding leads and the corresponding connection cables of the following rated characteristics:* System 1: 100 pF and rated voltage of 200 kV.* System 2: 100 pF and rated voltage of 700 V.* System 3: 500 nF and rated voltage of 10 V.* System 4: 5000 nF and rated voltage of 10 V.The coordinating laboratory was LCOE (Spain) and the participating institutes were LNE (France), VTT MIKES (Finland), RISE (Sweden), TÜBITAK UME (Türkiye), PTB (Germany) and LCOE (Spain). Participants used their best measurement procedures and setups in order to achieve their best calibration capabilities.Some of the institutes did not perform all the measurements, therefore comparison reference values are based sometimes in the results of only 4 institutes.Not all the laboratories measured at the same ambient temperature; to prevent this inconvenience and to be able to compare results, all capacitance values were corrected at 23 °C. The long drift of the high voltage capacitor of system 1, probably due to some small SF6 leakage, was also considered to calculate the CRV of each institute. Very good agreement between institutes is obtained for high voltage capacitance measurements (high voltage capacitance coefficient determination) and for low or high voltage dissipation factor measurements. Only a few low voltage measurements of capacitance are considered not compatible.Undertaking the work collaboratively through EURAMET proved to be an excellent tool to compare calibration and measurement capabilities of NMI and DI, as well as an opportunity for several institutes to improve their CMCs.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).