A power measurement system under non-sinusoidal loads (original) (raw)

Development of an Experimental Tool to Measure Power Quantities

Renewable Energy and Power Quality Journal

The development of an experimental flexible measurement system, DSP-based, to be used in a low voltage distribution grid is presented. The metering system, a key element in the liberalized electricity market, is developed for measuring and analyzing electrical power quantities under sinusoidal, nonsinusoidal, balanced or unbalanced conditions. Various issues involved in selecting a DSP, adopting the hardware architecture and developing software for the application are discussed. In this paper, the development of a tool capable of measuring power-related quantities based on power definition from IEEE Trial Std. 1459 is described. The general structure of the platform is explained alongside a more detailed discussion of the power measurement functions, hardware and software architecture and the comparison between them.

Ac Power Measurement System of Ume

imeko.org

Abstract: A high accuracy power measurement system, based on digital sampling techniques, has been developed and evaluated for the power frequencies at UME (National Metrology Institute of Turkey). The system is based on two sampling voltmeters and a ...

Sampling Rate Impact on Electrical Power Measurements Based on Conservative Power Theory

Energies

This article presents a study of the sampling rate effect on electrical power measurements whose definitions are based on the Conservative Power Theory (CPT). The definitions of active power and reactive power of the CPT were applied in the MATLAB® software by varying the sampling rate and using a digital power meter as a reference. The measurements were performed in scenarios with linear and non-linear loads. Due to the usage of an integral in the CPT calculus, an error was verified associated with the reactive power being inversely proportional to the sampling rate. From the present study, it is possible to conclude that depending on the sample rate, the errors associated with the reactive power measurements are unacceptable and make the CPT implementation unfeasible. The results also presented effective information about the minimal sampling rate needed to make these errors neglected and to assist in choosing suitable microprocessors for the digital implementation of the CPT. It ...

Parametric approach for power measurements under non-sinusoidal conditions

European Transactions on Electrical Power, 2007

The determination of the power components under non-sinusoidal conditions has received great attention in the last years. Digital instrumentation, provided of signal processing capability, allows to accomplish this task by evaluating the voltage and current spectral characteristics, from which all the needed power components can be derived. The paper presents a parametric method, based on a proper model for the input signal, able to perform the evaluation of the spectral components on the basis of data collected during short observation interval. This characteristic enhances the tracking capability of the estimation method and is useful when timevarying conditions must be detected.

Numerical algorithms for power measurements

1993

-sinusoidal situations. However, when the spectral characteristics of the input signals are known, all the power components corresponding to the different definitions can be easily evaluated. The paper presents some numerical algorithms suited for the estimation of the voltage and current spectra[ components, by which all the power components and other interesting load parameters can be evaluated. Simulation examples related to the power decomposition proposed by Czarnecki are reported, showing the high accuracy that can be obtained with numerical algorithms.

Alternative definitions of energy for power meters in non-sinusoidal systems

International Journal of Electrical Power & Energy Systems, 2015

Energy flow in sinusoidal systems is analyzed without problems by means of the traditional power definitions such as: apparent, active, and reactive, but these definitions are not properly applied in nonlinear loads. These loads present several distortions which are not correctly measured with the prevailing instruments designed for measuring energy and power. This is because a generalized set of power definitions is not available. In this paper, an alternative set of energy and power definitions is suggested for non-sinusoidal systems. Each definition is obtained through the analysis of power in the time domain. The proposed definitions add information to alleviate the power and energy measurement problem of the power meters, offer alternative indexes to measure the energy distribution, and allow calculations in transient and steady states. Furthermore, an experimental measurement of the proposed powers by means of a half-wave rectifier is shown.

A METHODOLOGY FOR QUALITY ASSURANCE IN ENERGY MEASUREMENTS UNDER NON-SINUSOIDAL CONDITIONS

The evaluation of the electrical energy flows is at the base of all operations connected to the commercial transactions in energy market. The assessment of "metrological quality" of the power/energy measuring apparatuses is well establishes in ideal sinusoidal conditions. But, with increasing diffusion of power electronics the typical characteristics of power network are far from sinusoidal one. In this paper a new methodology for quality assurance of energy meters in non sinusoidal operating conditions is reported. The description of methodology and some experimental results obtained are discussed in detail.

The registration of harmonic power by analog and digital power meters

IEEE Transactions on Instrumentation and Measurement, 1998

This paper discusses the measurement error of energy meters operating under harmonic distortion. A system to determine the magnitude of the error caused by an individual harmonic is used to generate curves on which the error introduced by different frequency components is displayed. An algorithm using these data to predict the resulting measurement error of a linearly operating energy meter registering under circumstances of any known harmonics in the voltage and the current is presented.