Algorithms and Models of Power Losses in Circuit Breakers of Shop Networks of Industrial Enterprises

The article discusses the main features of mechanical, chemical, thermal, and electrical processes occurring in the contact zones of the surfaces of contact connections of electrical devices. The parameters determining the value of power losses and power consumption in low voltage switching equipment are analyzed. The main characteristic features of the topology and technical condition under operation of the equipment of shop low-voltage industrial power supply networks are shown, the account of which is necessary for the analysis and assessment of power and electricity losses in such networks. A comparative analysis of the technical characteristics of automatic circuit breakers VA57-31 (KEAZ), NSX100 TM-D (Schneider Electric), DPX $^{3} 160$ (Legrand), $T_{\max }$ XT1 TMD (ABB) was carried out, which showed that the main technical parameters of the machines are close in their values. At the same time, it was found out that automatic switches of the VA57-3l series have the lowest value of power losses per pole $7.5 \mathrm{~W}$, whereas the automatic switches of the $T_{\max } \mathrm{XTl}$ TMD series have the highest value - 10 W. Therefore, the lowest value of power and electricity losses characterizes low-voltage electrical networks with installed automatic circuit breakers of the VA57-31 series, and the highest losses value occurs in in-shop systems with installed automatic circuit breakers $T_{\max } \mathrm{XTl}$ TMD by ABB. Using catalog data, the dependences of active power losses in circuit breakers on rated currents has been established. Algorithms have been developed and the obtained dependences have been modeled using approximating functions. The standard deviation of the compiled approximating functions has been calculated. Analytical expressions of the dynamics of power losses per pole are presented as a function of the rated current. The graphical dependences of the investigated parameters of low-voltage equipment are presented. The developed models are recommended to be used to increase the reliability of the assessment and refinement of the amount of active power and electricity losses in low-voltage electrical networks of industrial power supply systems, agrotechnical complexes, and enterprises of the public utility sector.