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On the Definition of Apparent Power

Canturk S., Balci M. E., Hocaoglu M. H.

Electrical Power Quality and Utilisation. Journal

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2015

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Vol. 18, iss. 2

1--9

EN

In this paper, the widely recognised apparent power definitions, which are Arithmetic, Vector, IEEE standard, DIN standard apparent power definitions and the apparent power definition of Mayordomo and Usaola, are rigorously reviewed, and their abilities on the measurement of the system’s power transfer efficiency are analysed by using a specially derived apparent power, which is calculated in terms of the total line losses of the system with and without the reactive power compensation. In the analyses, two major compensation strategies, namely the minimum line loss (MLL) and sinusoidal and balanced current (SBC) compensation strategies, are considered to determine the total line loss of the system with the compensation. Therefore, in a representative nonsinusoidal and unbalanced test system, the results are simulated by taking into account unbalance among the resistances of neutral and phase lines. The simulated results show that under nonsinusoidal and unbalanced conditions, the unbalance among the resistances of neutral and phase lines highly affects the system’s power transfer efficiency. Additionally, Mayordomo and Usaola’s apparent power definition can be used for proper measurement of the power transfer efficiency in the nonsinusoidal and unbalanced systems. On the other hand, the accuracies of the rest of the reviewed definitions considerably depends on unbalance among the resistances of neutral and phase lines. It should also be mentioned that the accuracies of the apparent power definitions are considerably not affected by the type of compensation strategy.

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A current decomposition-based method for computationally efficient implementation of power resolution meters in non-sinusoidal single-phase systems

Balci M. E., Hocaoglu M. H.

Metrology and Measurement Systems

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2013

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Vol. 20, nr 2

263--274

EN

For non-sinusoidal single-phase systems, the classical apparent power has been divided into various components using different techniques. These power resolutions generally aim at to provide a tool for the accurate determination of the maximum power factor achievable with a passive compensator and to measure the load's nonlinearity degree. This paper presents a current decomposition-based methodology that can be employed for computationally efficient implementation of the widely recognized non-sinusoidal power resolutions. The proposed measurement method and the original expressions of the power resolutions are comparatively evaluated by considering their computational complexity. The results show that the proposed method has a significant advantage in terms of computational efficiency for the simultaneous measurements of the powers when compared with the original expressions. Finally, in this paper, a PC-based power meter is developed using the proposed measurement method via the LabVIEW programme.

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.