INTERLABORATORY COMPARISONS OF CALIBRATION RESULTS OF THREE-PHASE ELECTRICAL ENERGY METERS

Reliable measurement of electric energy is of great importance both in industry and for household consumers of both single-phase and three-phase networks. Interlaboratory comparisons (ILCs) are one of the experimental forms of confirming the scope of accreditation of calibration laboratories (CLs). The article is devoted to the analysis of the results of the ILC of a three-phase electric energy meter, which was conducted in 2025. The ILC was conducted with the participation of accredited CLs from Ukraine and Israel. A feature of this ILC was the calibration of the meter both for three phases in general and for each phase separately. Calibration was carried out with a nominal AC voltage of 230 V, frequency 50 Hz, currents from 2.5 A to 100 A at KP 1.0 and 0.5 for positive and negative flow. Processing of the primary ILC data received from the laboratories was carried out using special software “InterLab 1.0”, developed in UMTS. The deviation of the results obtained by each laboratory was determined and the consistency of the results obtained was assessed taking into account the measurement uncertainty using the criterion of performance statistics. In general, the laboratories obtained satisfactory results with good consistency. The laboratories fully meet the established requirements for the En number and have confirmed their technical competence during the calibration of meters in accordance with the requirements of the international standard ISO/IEC 17025. The results of the ILC allow for the mutual recognition of the results of the calibration of electricity meters by the national accreditation bodies that accredited these CLs.