Analysis of electromagnetic and thermal processes in a grounding device at a voltage of 10 kV

The paper considers electromagnetic and thermal processes in the system of current-carrying elements of the grounding device in the medium voltage switchgear cabinet, occurring during a short circuit. The short-circuit mode is a necessary stage in testing switching devices. The occurrence of large currents leads to significant electrodynamic and thermal effects. Resistance to short-circuit currents depends on the duration, shape of the current curve, as well as on the distribution of the current density over the cross-section of the current-carrying elements of the device. When designing new devices, a set of calculations and tests is carried out. The use of analytical calculation methods does not allow to fully take into account the influence of various factors. The aim of the article is to develop a numerical model of electromagnetic and thermal processes in a grounding device to improve calculation accuracy, reduce testing time, and determine the maximum permissible current values when assessing thermal stability. The problem is solved using a multiphysical electrothermal model built using the finite element method. The obtained results of modeling electromagnetic and thermal fields in the design of the ground electrode system allow us to determine the most loaded sections and provide measures to change the design in order to increase the thermal and dynamic resistance of the ground electrode system.