The object of research of the Thesis is the arc current and the chopping current occurring inside the vacuum interrupter. The aim of the Thesis is to use additional Petersen reactor coils for automatic adjustment of the switching process, as well as optimization of LTT thyristor set implementation for suppressing arc currents and chopping currents. In addition, the solution of the mathematical model synthesis problem obtains the result of static process modeling as a softswitching circuit breaker of a vacuum interrupter. Although there are three negative phenomena, mainly inside vacuum interrupter could be disruptive the insulation levels in medium voltage apparatus. However, there are also other disruptive phenomena, which are not so dangerous. 1. Restrikes of voltages – fast oscillating voltages. 2. Prestrikes over voltages – fast oscillating currents. 3. Multiple re ignitions. 4. Voltage escalation – oscillations phenomena. 5. Post-arc currents. 6. Thermal – Joule heating. The author of the Thesis proposes a new invention, a softswitching circuit breaker, which completely eliminates arc current, chopping current and transient overvoltage.