Tomasz Kuczek

Simulations of electric arc behavior in hybrid LV switches

In this paper the commutation mechanism based on LV mechanical circuit breaker and parallel semiconductor device is discussed. This hybrid switch comprises electromechanical relay connected in parallel with semiconductor branch controlled by microprocessor unit. The work presented herein covers both laboratory experiments as well as EMTP-ATP simulations, where modeling of electric arc behavior was based on Cassie-Mayr black-box model with accordingly estimated parameters. Such analyses are especially important in case of hybrid switching systems due to possibility of estimating system response during transient conditions (overvoltages, current distribution, power and energy dissipated at semiconductor branch, power and energy of electric arc, etc.). Presented model provides satisfactory convergence of simulation results with data obtained during experiments.

Modeling of Repetitive Ignitions in Switching Devices: Case Studies on Vacuum Circuit Breaker and GIS Disconnector

Repetitive ignitions of electric arc during switching operation may result in generating Fast and Very Fast Transients (FT and VFT) and thus require analyses to ensure reliable system operation. The paper presents a common approach for modeling and simulation of such phenomenon for two types of switching devices: Vacuum Circuit Breakers (VCB) and GIS disconnectors. In each case, the associated (VFT) are modeled with the use of a case-specific Breakdown Voltage Characteristic (BDV), characterizing the switching process, and with the use of case-specific power system conditions. Two case studies are presented. For Vacuum Circuit Breaker, a switching operation of un-loaded transformer is presented. For GIS disconnector, switching of short bus-bar during the disconnector type testing is presented.

Application of bidirectional transient voltage suppressor for electric arc suppression in LV switches - simulation and laboratory case study

This paper presents the analysis of bidirectional Transient Voltage Suppressor (TVS) application for limitation of the electric arc energy in a low voltage circuit. The study employs both simulations and laboratory experiments, which were conducted to present inductive current breaking procedure with use of a standard switch and a switch with passive arc suppressor connected in parallel. EMTP-ATP simulations, where modeling of electric arc behavior was based on Cassie-Mayr black-box model with accordingly estimated parameters, provided satisfactory convergence with data obtained during experiments. Therefore, it can be concluded that in this case, the simulation is an accurate representation of physical nature of the analyzed switching process. Hence, developed computer model can be used to analyze switching overvoltages, current distribution, power and energy dissipated at semiconductor branch, as well as, power and energy of electric arc.