Improvement of calibration capabilities with an a posteriori evaluation of the lighting impulse international comparison EURAMET.EM-S42

By the evaluation of the EURAMET.EM-S42 intercomparison results, the Laboratorio Alte Tensioni e Forti Correnti (LATFC) of Istituto Nazionale di Ricerca Metrologica (INRiM, Italy NMI) starts an analysis of the calibration capabilities with the developed measuring system for lightning impulse voltages. This paper addresses the issue of the expanded uncertainty re-evaluation for the INRiM’s CMCs up to 200 kV according to a new analysis of the comparison reference value (CRV), without affecting the results of the other participants in the comparison for all the involved lighting impulse parameters. A validation of the new uncertainty values has been performed by means the calculation, for some test data waveforms extract for reference standard IEC 61083 - 2, of the convolution with the measured divider step response.