Effects of Fast Elongation on Switching Arcs Characteristics in Fast Air Switches

Abstract

This paper is devoted to investigating the effects of high-speed elongation of arcs inside ultra-fast switches (ucontact≈ 5–80 m/s), through a 2-D time-dependent model, in Cartesian coordinates. Two air arcs in series, one between a stationary anode and a moving cathode and the other between a stationary cathode and a moving anode in the arc chamber, are considered. A variable speed experimental setup through a Thomson drive actuator is designed to support this study. A computational fluid dynamics (CFD) equations system is solved for fluid velocity, pressure, temperature, and electric potential, as well as the magnetic vector potential. Electron emission mechanisms on the contact surface and induced current density due to magnetic field changes are also considered to describe the arc root formation, arc bending, lengthening, and calculating the arc current density, as well as the contact temperatures, in a better way. Data processing techniques are utilized to derive instantaneous core shape and profiles of the arc to investigate thermo-electrical characteristics during the elongation progress. The results are compared with another experimentally verified magnetohydrodynamics model of a fixed-length, free-burning arc in the air. The simulation and experimental results confirm each other.

Metal vapor content of an electric arc initiated by exploding wire in a model N2 circuit breaker: simulation and experiment

“…As is shown in figure 16(c) at pressures between 20 and 80 bar, the copper content of the arc initiated by the ignition wire, is between 2% and 45%, and the effect of nozzles on the mixture ratio is not negligible. So, the commonly used method of utilizing EEW in the model CBs instead of contact separation does not apply to SCFCB and complex actuator design, complicated simulation, and measuring methods [22,55] due to the arc elongation in a dense medium [56] is required for an accurate study.…”

A Method for Analysing and Characterizing the Arc Cooling Effect of Different Gases in Strong Axial Flow With SF6 and Air as Examples

“…Laminar flow prediction of the critical RRRV [25] is at least one order of magnitude lower than the measurement for both nitrogen and SF6 [23]. The importance of turbulence in switching arcs was also confirmed by the work in [26] [27].…”

Fluid-chemical modeling of the near-cathode sheath formation process in a high current broken in DC air circuit breaker

“…[1] DCCB is now developing towards extinguishing the arc more effectively and rapidly, so the arc needs to be stretched rapidly when generated in the DCCB. [2] Metal splitter plates are usually used in a DCCB to extinguish the arc, whose principle is to cut the arc into series of sub-arcs through the splitter plates. The voltage drop of the near-electrode sheath formed by the sub-arcs can increase the arc voltage to the supply voltage, so that the arc is extinguished.…”