Computational Model for the Dimensioning of Neutral Conductor in Low Voltage Power Networks Operating in Various Regimes

Abstract

In low-voltage electrical installations, power issues having the highest incidence are related to the presence of higher harmonics in the waveform spectrum of the absorbed currents and also to the imbalances in the three-phase distributions. The deforming (non-sinusoidal) regime becomes even more undesirable for networks having a low short-circuit response factor (high impedance systems) and, normally, it also causes distortion of waveforms of the supply voltage. Current unbalance (more rarely) is typically seen in networks that supply single-phase consumers (where virtually no balancing is possible on each phase) causing unwanted effects in installations. In this paper, we will investigate how the neutral conductor should be dimensioned inside low-voltage three-phase electric installations, where these deforming modes and / or load imbalances may occur. A new algorithm, easy to implement in any software environment, dedicated for dimensioning the neutral conductor of that installation, will be also described.