The article considers the current problem of ensuring fire safety in low-voltage power supply systems of residential and public buildings in modern conditions. The analysis shows that even with formal compliance with all regulatory requirements at all stages of the life cycle of an electrical installation, there remains a risk of specific, potentially fire-hazardous modes of operation. These modes, which often go unnoticed, are characterized by significant non-sinusoidality and asymmetry of currents and voltages, which leads to additional heating of the network elements. The purpose of the study is to analyze the magnitude of the current in the zero wire of the 0.4 kV network of an apartment building with a predominance of household nonlinear load. Special attention is paid to the mechanism of summing currents of higher harmonics, in particular the third harmonic multiple of three, in a neutral conductor, which leads to its overload (and, as a result, overheating) even with an externally balanced phase load. Based on the analysis of the simulation results, the necessity of supplementing the current regulatory framework with new indicators and criteria is justified, which make it possible to identify and normalize such hidden dangerous modes that remain out of sight during traditional voltage parameter monitoring.
KOZLOVA et al. (Mon,) studied this question.