METHOD OF MEASURING ELECTRICITY WITH A DIGITAL METER

Abstract

The object of research is an electricity digital meter. The subject is the method of measuring active and reactive energy, which is consumed by the load. The goal of the research is to increase the accuracy of electricity measurement in real-time using a digital meter. Electricity meters, which are widely used as part of commercial electricity metering units, are characterized by low measurement accuracy in the presence of semiconductor converters in the power grid. Reduction of measurement error is possible by using an algorithm, which takes into account higher harmonics in the current and voltage. As a result of the study the method of measuring electricity with a digital meter has been improved. The method uses the discrete Fourier transform to estimate amplitudes and frequencies of the current and voltage from the corresponding sensors. As a result, root mean square values of harmonic components of current and voltage, active and reactive powers are obtained. Using numerical integration of the discrete power readings, the active and reactive energies values can be determined. The proposed method is different from the known ones by considering of higher harmonic components to the consumed energy. Thanks to this, the accuracy of electricity metering can be increased. The use of such a method is especially relevant in power supply systems with semiconductor converters. Taking into account higher harmonics allows to reduce fraud when using unaccounted energy at high frequency. The accuracy of power flow accounting also increases, which is relevant for Micro and Smart Grid power grids. The developed method can be used to improve the software of commercial electricity metering units on a digital element base, build new devices, as part of energy meters of various functional purposes. The method also allows to improve the software of microprocessor terminals within the digital substations.