Asymmetric modes of 0.4 kV electric networks, calculation methods

This paper examines the characteristics of symmetrical and asymmetrical operating modes of three-phase 0.4 kV electrical networks. It is noted that the symmetry of phase voltages and currents is key to the efficient and reliable operation of electrical equipment, while asymmetry resulting from uneven distribution of single-phase loads, damage, or transients leads to increased losses, overheating of electric motor windings, reduced service life of electrical equipment, and deterioration in power quality. This paper analyzes methods for assessing asymmetry based on the theory of symmetrical components for voltages and currents, presents calculated dependencies of asymmetry coefficients, and specifies the standard values established by GOST 32144-2013. Modern approaches to studying asymmetrical modes based on computer modeling in specialized software packages-RastrWin3, DIgSILENT PowerFactory, ETAP, and NEPLAN-are also considered.