The research involved the determination of physical factors affecting the generation of arc column length disturbances in electrotechnological devices. The article contains a justification related to the selection of the Pentegov model for representing the dynamic characteristics of a sinusoidal current powered arc. The research also included the modification of the Ayrton formula approximating static voltage-current characteristics by taking into consideration arc column length random disturbances as well as the development of an arc macro-model and simulations of processes in a simple circuit using MATLAB-Simulink software. The research demonstrated the efficiency of the three measurement method for determining the Pentegov model parameters in conditions arc column length disturbances.