Search

Currently, electricity is treated as commodity that should be delivered from a distributor to a consumer with a certain quality. The power quality is defined by the set of measures with specific limit values. One of the basic measures is the Total Harmonic Distortion (THD), which allows to assess the level of the voltage distortion. The measurement of THD ratio should be carried out in accordance with the normative specification. It is assumed that this requirement is met by class A power quality analyzers. Currently, measures are taken to monitor power quality in a large number of measurement points with the use of smart energy meters that are part of the Advanced Metering Infrastructure (AMI). The paper presents the problem of THD ratio measurement by AMI meters if voltage fluctuations occur. In such situation, inconsistency in measurement results of AMI meters and class A power quality analyzers occurs. The problem is presented on the basis of laboratory study results in which disturbances in power grid are recreated. [ABSTRACT FROM AUTHOR]

It is important to conduct the examination of reactive power and energy instruments in normal operating conditions, due to their place in the regulated trade of electrical energy. The challenge arises when the normal operating conditions encompass non-sinusoidal voltages and currents, for two main reasons: the fact that the term reactive power/energy is not unambiguously defined in case of harmonically polluted environment and the fact that the measurement algorithm implemented in the meter is usually not explicitly presented by the producer. Different algorithms provide the same result in case of sinusoidal signals, while in case of harmonics the instrument's performance may vary significantly, when different power theories are adopted. In the paper, a commercially available reactive energy electricity meter is tested with harmonically distorted voltage and current signals, and an analysis of its output is performed from the perspective of the implemented measuring algorithm, which is not known a priori. The tests encompass alteration of different waveform parameters and the instrument's output is analyzed from the perspective of several reactive power theories. The conclusion of the analysis results in the meter's performance feature illustration in correlation with different harmonic parameters and different reference conditions. [ABSTRACT FROM AUTHOR]

This paper presents an error analysis of the estimation of energy meter correction factor (CF) using a remote non-invasive technique. A method of the CF estimation based on the comparison of synchronously detected power steps in power consumption profiles of meter under test and reference meter is elaborated. The dependence of meter CF estimation uncertainty upon the magnitude of power steps, the number of power steps per observation interval, and the number of meters under test monitored by one reference meter is approximated. The synthesized consumer active power profiles are used to obtain training data points that are fit by these approximating equations. [ABSTRACT FROM AUTHOR]