Özet:

Research of improving the reliability of electric power supply system with electric motor load voltage of 0,4 kV by rationing of simultaneously contact breaking of switching devices and the use of electric protection devices integrated with elements of adaptability are conducted. A study of the conditions of maximum switching overvoltage considering simultaneously contact breaking of switching devices and rationing of specified time are conducted. These studies are needed to determine the levels of asymmetry, nonsinusoidality of the voltage and switching surges in the electric power supply systems with electric motor voltage of 0,4 kV with switching by vacuum contactors, which then affect the quality of electricity. It is proposed a non-simultaneity standard of contact breaking of low-voltage switching devices, and method of non-simultaneity detection of contact breaking of low-voltage switching devices. It is developed a mathematical model of "electric network – integrated device for electric motor protection – induction motor", which differs from the known by ability to complex research of electromechanical processes and modes of switching devices, devices for integrated motor protection. Dependences of non-simultaneity impact of contact closure of low-voltage switching devices, which is guided by an asynchronous motor at switching surge, are determined. It is determined that the maximum overvoltage occurs under the following conditions: the third contact of the switching device is breaking with delay relative to the first, which are breaking simultaneously; breaking the third contact occurs after the extinction of the currents flowing through the second and third contacts. For this purpose, it is proposed the method of non-simultaneity detection of contact breaking of switching electric devices, which, in turn, will help determine the level of asymmetry, nonsinusoidality of the voltage and switching overvoltage in the system electric power supply system of 0,4 kV switching by vacuum contactors. Author Biographies Василь Ярославович Бунько, Branch of National University of Life and Environmental Sciences of Ukraine «Berezhany Agrotechnical Institute», Str. Academichna, 20, Berezhany, Ukraine, 47501 Candidate of Technical Science, Associate Professor Department of power industry and automation

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