On the Initial Recovering Strength of Low-Voltage Switching Devices in the Range of Short-Circuit Currents

It is shown that the initial recovering strength of low-voltage switching devices in the range of short-circuit currents is largely determined by the geometric parameters of arc-extinguishing grid plates, the distances between them, and the design features of contact arc-extinguishing systems. A method for determining the initial recovering strength of circuit breakers in a short-circuit current interruption mode is proposed. The analysis of the initial recovering strength of circuit breakers from various manufacturers allows obtaining the dependences of this parameter on the design features and rated currents of these breakers. The distribution of the electric field strength at the arc’s entering the grid and the forces of the interaction of the rupturing arc with the grid plates are simulated in the COMSOL Multiphysics software package for different plate cutout shapes. The relationship between the values of the interaction forces and the initial recovering strength is shown.