Dielectric recovery in a high-voltage circuit breaker in SF₆

Abstract

The dielectric recovery in high-voltage circuit breakers after interruption of high-current amplitudes was investigated experimentally in a test device. Various current amplitudes were tested, which cover a typical range of practical interest. Simulations with computational fluid dynamics together with electric field simulations allowed one to deduce the physical parameters in the region where the breakdown was decided. A leader inception model using these parameters explains under which condition leader inception occurs; causing breakdown of the gap. Based on this model scaling laws for leader inception are given.

Perspectives on Research on High Voltage Gas Circuit Breakers

“…This can happen in the former arc channel during the early dielectric recovery within less than 100 ls after CZ, typically. During the later dielectric recovery, it is completely independent of the previous arc channel [7]. Usually an electric breakdown event associated with a thermal failure exhibits a slow transition from the TRV to the arc voltage of the reestablished arc.…”

“…Streamer and leader models can serve to describe the electric breakdown during the dielectric recovery [7], i.e. breakdown mechanisms under these conditions are similar to those in cold SF 6 .…”

“…Breakdown models for the relevant conditions, as e.g. [7][8][9] [27] Plasma Chem Plasma Process the early dielectric recovery need further attention. The dielectric breakdown under the conditions of high ion concentrations, i.e.…”

Circuit Level Model of Miniature Circuit Breakers

“…In a MCB, current interruption is obtained thanks to magnetic fields by guiding the arc in a region where it is fragmented by transversal ferromagnetic splitter plates [12]. Electron transitions from the solid phase, i.e, from an anode or a cathode, into the plasma phase are associated to roughly current independent surfacic voltage drops (in the [10,20] V range per anode-cathode pair, depending on plate material). Consequently, multiplying the number of serial arc roots, by means of for example 10 splitter plates, amounts to sensibly increasing the total arc voltage drop to a value comparable to the supply voltage.…”

Recovery of Alumina Nanocapacitors after High Voltage Breakdown

“…In gas circuit breakers, widely used in high-voltage transmission and distribution networks, the dielectric breakdown plays the key role for a successful interruption of high short circuit currents 11 , 12 . The subsequent recovery of a gaseous dielectric, during which the gas recombines, cools, and recovers its initial dielectric strength, is one of the main stages of the breaker operation.…”