Advanced Instrument For Field Calibration of Electrical Energy Meters

Calibration of electrical energy meters is coming up as a metrological concern. The latest European Union (EU) directives about measuring instruments adopted for commercial transactions state that their accuracy has to be verified in actual operating conditions. This requirement is leaving all laboratories involved in energy meter calibration in serious difficulty because this kind of metrological verification is, at the moment, still not fully developed or even clarified in all involved aspects. In this paper, a measurement equipment for the calibration of energy meters is presented. Its structure and metrological characterization are discussed. To improve its performances without increasing its costs, two online digital compensation procedures have been realized and are shown: one increases the spectral purity of test signals and one corrects the transducer frequency response. Experimental results relating metrological characterization have shown that the so-realized calibrator is suitable for the onsite calibration of energy meters.