The article is devoted to the development of a mathematical model of an insulator breakdown and the methodology for assessing the development of a breakdown. The main calculation expressions are presented in the article. The design of a real insulator (the outdoor voltage insulator of 35 kV type IOSK 3/35 UHL1) is presented as an example of the technique applicability. The datasheet of this outdoor isolator was used to verify the mathematical model and the results of numerical simulation. The results of numerical simulation and the outdoor insulator breakdown voltage are presented in the article. Numerical simulation was carried out in Comsol Multiphysics software. The obtained results can be applied in the engineering design of outdoor insulators and elements of electrical constructions.

The article presents the numerical simulation results of the high frequency generator (electron tube type) with self-excitation in the Simulink. The main structural element of this generator is an electron tube GU-66A. Digitization characteristics of the electron tube is made. A mathematical model of the HF generator, taking into account the anode and grid characteristics of GU-66A according to the passport data of the product, has been developed. The parameters of the HF generator circuit are determined. A plasma-chemical reactor and its equivalent electrical parameters (set in a wide range of accepted values) are used as a load oscillation circuit. The developed model allows to determine the optimal parameters of the HF generator, as well as to predict operating modes, providing continuous supply of HF power for a long time (more than 20 hours). The equivalent electrical parameters of the plasma-chemical reactor are designed to ignite plasma discharges in argon and gas mixtures based on argon at atmospheric pressure.

The experimental results of the circuit breaker interrupting capacity are presented in the article. The scheme of the experimental workbench and diagnostic methods are described. The study was performed using high-speed shooting methods. The high-speed shooting results and diagrams for different modes are presented. The analysis of the arc divider geometry influence on the extinguishing process for different modes and power factor is completed. A parametric study of the influence of the power factor, the interrupting current magnitude and the moment of switching on the extinction of the electric arc in the circuit breaker is also performed. The influence of the arc chute geometry on the formation of a new arc attachment point is shown in the article. The test was carried out on the basis of a specially developed prototype of a low-voltage circuit breaker (AC). The obtained results can be used when designing a low-voltage circuit breaker (AC).

The experimental results of the hollow electrodes erosion resistance considering a pilot arc re-ignition during plasma torches operating, are presented in the paper. A high voltage alternating current oscillator is used to simulate an initial process instability. The electrical circuit of the experimental setup with a pulsed discharge current up to 2 kA with time parameter 8/250 and a follow current of 800 A at industrial frequency is described. Four electrodes materials of tungsten (W), iron (Fe), copper (Cu), copper with a sprayed nickel+iron powder (Cu-Ni-Fe) are investigated. X-ray patterns of the different electrode surfaces are demonstrated after 4–9 pulses and one pulse with follow current impacts. The electric charge is calculated by integrating the obtained discharge current to assess the erosion coefficient. The following decreasing order of the electrical erosion resistance is determined: W - Fe - Cu-Ni-Fe - Cu.

The article is devoted to the study of heat transfer processes of the high-current AC circuit breaker contact system. The creation of a mathematical model is based on the application of well-known physical laws such as the Joule-Lenz and Fourier laws, which describe physical processes in the form of partial differential equations. Cooper-Mikic-Yovanovich correlation is used for evaluation of thermal and electrical contact conductance. The developed mathematical model is verified by the results of experimental studies. The calculation of the composite material properties for numerical simulation of heat transfer processes is presented. The calculation is presented for the actual design and materials of the circuit breaker.