Measurement Analysis of Three Phase Intelligent Electricity Meter Based on Nonlinear Load

In order to improve the accuracy of non-linear load measurement in three-phase smart meters, the author proposes a measurement analysis of three-phase smart meters based on non-linear loads. The author analyzed the nonlinearity of most differential amplifiers in metering chips, theoretically analyzed the reasons for low metering accuracy under non-linear loads, and analyzed and designed the reasons for phase errors in electric energy meters. The results indicate that: At 5%, 20%, 100%, and 120% of the rated current, the phase error limits of the current transformer are ± 15 ', ± 8', ± 5 ', and ± 5', respectively. At 5% of the rated current, the phase error generated by the transformer reaches 100% of the rated current and 3 times that of 120%. This is also the reason for the large error in measuring small current signals in electric energy meters. The author provides a precise analysis and design method for nonlinear load measurement of three-phase smart meters to improve the performance of measurement chips and improve the accuracy of nonlinear load measurement.