ANALYSIS OF ENERGY FLOWS IN POWER SUPPLY SYSTEMS WITH NON-LINEAR LOAD
Keywords:electric network, power supply system, non-linear load, non-sinusoidal voltage, high harmonics, power losses, neutral line.
The problem of the non-sinusoidal modes analysis of the power supply system with non-linear elements and their influence on the efficiency of the power transmission are considered. It is carried out numerical analysis of electric energy flows for three phase power supply system with sinusoidal electromotive force source, linear active load and non-linear elements (diodes). Power transfer is considered as distribution of the primary power flow from source. The part of this flow is converted by non-linear elements and return into the network like secondary power stream of zero sequence and high harmonics which is consumed by resistance elements and causes additional power losses. As a result transporting efficiency and power factor are reduced and energy quality becomes worse. In order to improve the quality of electricity, it is proposed to normalize the relative value of the reactive power of distortion for non-linear electric collectors and to oblige manufacturers of electrical products to complete them with filters of higher harmonics. With the purpose of correct selection of the type and power of compensating devices and monitoring the parameters of the electric network mode, it is proposed to expand the functionality of electronic meters by dividing the reactive power into two components - shear power and distortion power, and for the objective analysis of energy flows, it is proposed to standardize the reactive power of distortion. It is shown that in such system current in neutral line increases due to overlaying of zero sequence harmonics currents. This should be taking into account during neutral line cross-section choice and power losses calculation.
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