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Testing Of energy meters under three-phase determined and random nonsinusoidal conditions

Olencki A., Mróz P.

Metrology and Measurement Systems

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2014

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Vol. 21, nr 2

217--232

EN

Electric energy meters are designed to account energy under sinusoidal and nonsinusoidal conditions, because both, old and new standards for energy meters require testing their accuracy under different conditions. The latest EN 50470 standard increases the range of meter testing under nonsinusoidal conditions, introducing new shapes of test signals such as the phase fired waveform or the burst fired waveform. This paper discusses calibration problems of electronic revenue energy meters for direct connection and for connection through current transformers, and it proposes a new calibration procedure which reproduces normal operating conditions better: three-phase configurations of measurement systems, load range during meter testing or shapes of test signals. Recently, modern Electrical Power Standards, also known as Power Calibrators, enable automatic testing of various types of electrical devices, including electricity meters in their normal operating conditions. This article presents examples of single and multi position fully automatic test systems, which employ Power/Energy Calibrator from Poland as the precision source with programmed waveforms of three phase voltages up to 560 V and currents up to 120 A conforming to EN 50470, or with random waveforms generated by PC software random wave generator. Measurement uncertainty of the energy meters under different nonsinusoidal conditions using a test system with reference to accuracy of the power calibrator or to the reference meter, are discussed. Comparative analysis of test results for different shapes of voltage and current signals is presented in the conclusions of this paper.

2

On Power Factor Improvement by Lossless Linear Filters under Nonlinear Nonsinusoidal Conditions

del Puerto-Flores D., Ortega R., Scherpen J. M. A.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 1

112-117

EN

Recently, it has been established that the problem of power factor compensation for nonlinear loads with nonsinusoidal source voltage can be recast in terms of the property of cyclodissipativity. The purpose of this brief note is to review and to illustrate the application of this framework to the practical of passive reactive compensation of linear loads with a nonsinusoidal source voltage. We give criteria for determining the optimal values of the compensator parameters that depend of the spectral line of load susceptance and voltage source.

PL

Stwierdzono ostatnio, że problem poprawy współczynnika mocy odbiornikowi nieliniowych zasilanych napięciem niesinusoidalnym może być rozpatrywany z punktu widzenia cyklo-rozpraszania (cyclodissipativity). Celem tego artykułu jest przegląd i pokazanie zastosowania takiego podejścia przy bezstratnej kompensacji odbiornikowi liniowych zasilanych napięciem niesinusoidalnym. Podane zostały kryteria do określenia optymalnych wartości parametrów kompensatora, które zależą; od charakterystyki widmowej susceptancji obciążenie i źródła napięcia.

3

Effects of source voltage harmonics on power factor compensation in ac chopper circuits

Balci M. E., Hocaoglu M. H.

Electrical Power Quality and Utilisation. Journal

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2008

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Vol. 14, iss. 1

53--60

EN

In recent years, the detailed modelling of power electronic devices and their behaviours on various system conditions are a great concern of the power industries and customers. One of the widely proliferated such devices is the triac controlled ac choppers. Although these types of devices have important application areas, their poor power factor is the main obstacle for the large scale implementation in power systems. This paper presents an analysis on the behaviour of a single phase load composed with triac controlled ac chopper during the reactive power compensation with a basic capacitor in nonsinusoidal voltage case. The results of these analysis show that the distortion of voltage improves power factor, which is contradicting with previous findings, for the high conduction angles of triac controlled ac chopper. In addition, it is observed that the performance of power factor improvement with a basic capacitor is noticeably affected by the phase angles of voltage harmonics, which is an extensively ignored issue in the literature.