Özet:

The development of standards based on quantum effects, in particular, alternating voltage synthesizers, has not yet allowed defining the metrological characteristics of measuring instruments for alternating voltage up to 1,000 V at a frequency up to 1 MHz. Therefore, a comparative analysis of international comparisons of national standards has summarized the possibilities of metrological support with the use of AC/DC voltage transfer standards. The conducted analytical and experimental studies give grounds to state the decisive contribution of national metrological institutes in the formation of the modern equivalence level of AC/DC voltage transfer standards. A comparative analysis of the uncertainty of measurements achieved by the leading national metrology institutes has made it possible to distinguish the most accurate type of thermal voltage converters based on the thermocouples connected in series. Such a measuring instrument allows measuring AC/DC transfer difference with an uncertainty of less than 1 μV/V at certain points of the measuring range. Consideration of the capabilities of the travelling standards to ensure a stable storage of a value of AC/DC voltage transfer difference has indicated the advantage of the thermal converter of an indicated above type, relative to the other types used in the comparisons of AC/DC transfer standards. The calculation of stability coefficients for different types of standards has shown an approximately twofold advantage of thermal converters based on the thermocouple comparing with multi-range thermal comparators on the basis of the root-mean-square voltage sensor. The results of the considered comparisons have shown that there were no advantages of any of the measurement schemes used by the laboratories since no relation has been found between the reported measurement uncertainty and the scheme.The results of the estimation of the frequency influence of the input voltage on the transformation coefficient of the AC/DC voltage transfer standards of the two types have given the grounds to neglect correcting the contribution of this source of uncertainty. The proposed approach to measuring the AC/DC transfer difference with providing the connection with a direct definition allows us to estimate more appropriately this metrological characteristic in two ways Author Biographies Oleh Velychko, State Enterprise “All-Ukrainian State Scientific and Production Centre for Standardization, Metrology, Certification and Protection of Consumer”, (SE “Ukrmetrteststandard”) Metrolohychna str., 4, Kyiv, Ukraine, 03143 Doctor of Technical Sciences, Professor, Director Scientific and Production Institute of Electromagnetic Measurements

Anahtar Kelimeler: