Mathematical Modeling of Arc Faults in Networks with Low Single Phase-to-Ground Fault Currents

¹ Electrical Power Systems Design and Development Department, JSC “Scientific and Technical Center of Unified Power System”, 1 lit A Kurchatov Str., St. Petersburg, 194223, Russia
² Higher school of Electric Power Systems, Institute of Energy, Peter the Great St. Petersburg Polytechnic University, 29 Polytechnicheskaya Str., St. Petersburg, 195251, Russia
³ Scuola di Ingegneria Industriale e dell’Informazione – MI, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy

^* Corresponding author: petrova4anna@gmail.com

Abstract

The article comprises the results of the research defining open-flame arcs self-quenching conditions in the event of a single phase-to-ground fault in overhead medium-voltage distribution networks according to existing theories of arc extinguishing. The calculations included metallic and arc faults modeling in a network with low phase-to-ground fault current. The arc gap simulation based on the mathematical channel model of a cylindrically symmetrical upright arc stabilized by rising convective gas flow was carried out in ATPDraw software program. The single phase-to-ground arc fault calculations results indicated an increase in high-frequency currents’ attenuation rate during transient processes as well as a reduce reduction in the electric arc lifetime from 8 ms to 2 ms in case of the breakdown voltage decrease from the peak value to zero. Notably, in case of low single phase-to-ground fault current the arc extinguishing took place at the first high-frequency current zero. For the cases of nonzero breakdown voltages, the electric arc extinguishing was detected at the fundamental frequency current component zero-crossing instant. The maximum overvoltage ratio of K = 2.8 was obtained as athe result of the single phase-to-ground fault at the peak phase voltage.