ACTIVE ELECTRICITY METERS ERROR ANALYSIS IN CASE OF HARMONICALLY DISTORTED VOLTAGES AND CURRENTS

Abstract

High order harmonic components in voltage and current signals are nowadays more prevalent in power grids at any voltage level, therefore demands for accurate measurements of the system’s parameters go beyond the performance of instruments under pure sine wave conditions. This topic is highly challenging, especially in domain of electricity meters intended for legal metrology purposes, i.e. for billing in the regulated trade of electrical energy. Test procedures for examination of electricity meters’ output in case of harmonically distorted signals are proposed in several international standards and recommendations. The drawbacks of the signals presented in these documents are the lack of complexity and random behavior of single harmonic component’s amplitude and phase shift. Because many types of electricity meters are used worldwide, different output is expected for instruments based on different measurement principles. For faithful presentation of meters’ errors in case of harmonics, several devices are about to be tested with random distorted signals, by using different currents and phase shifts.