[en] The Joule heating of an inhomogeneous, temperature dependent resistivity conductor is studied numerically when a time-varying current flows through it. The bidimensionnel numerical model computes the temperature and current distributions at each time step consistently. A simple experimental verification is presented, together with one example showing how the model may be exploited

[en] Primary erosion conception of a plasma current breaker suggested an appearance of an vacuum gap near cathode, through which electromagnetic energy may reach the load. The theory of two-dimensional flows of electrons and ions of a quasineutral plasma near electrodes is given

[en] A fast circuit breaker operated by an electromagnetic command has been realized. It can open very high currents in times in order of a few microseconds. By means of electromagnetic forces, a conductor is sent against rods and thus cut. The current is then transferred onto a fuse placed in parallel. The explosion of the fuse opens the circuit. A simplified set up has permitted to test some performances of the switch. A 240kA current has been opened in 6μs and a 5kV peak voltage simultaneously generated (half-width : 3μs). The transfer of a 130kA current has been realized in a time as small as 2μs

[en] The circuit breaker presented here is capable of interrupting a 10kA current within 1μs and then sustain an over voltage of the order of 20kV for a 3mm insulation width. The construction is of the mechanical rupture type in which the replacement of a piece of conductor by an insulator is ensured by means of the explosion of a stoichiometric mixture of hydrogen and oxygen. The current is then transfered into a fuse which finally transfers the energy to the load or opens the circuit

No abstract available

No abstract available

[en] Influence of the shock wave on the turbulence in a supersonic nozzle was investigated for a SF₆ puffer circuit breaker interruption process. Turbulence is enlarged through the shock wave. Baroclinic generation of vortex causes flow separation and broadening of the arc cross section. V-I characteristics are slightly modified due to the shock wave's influence.

[en] Rotating arc circuit breakers are of increasing interest at present for a number of reasons. These relate to their perceived open-quote soft close-quote interruption capability and their potential for cost savings through low-energy operation. Such advantages have led to a growth in the application of rotating arc geometries to low voltage interrupters, from 11 to 25kV but also at medium voltage levels, such as the autopuffer. While it is known that rotating arcs must undergo some deformation as a result of their movement, the effects of such deformations have remained largely unreported. The aim of this paper is to present data on the deformation of a swiftly rotating arc column and the effect this has on the subsequent behaviour of the column. Far from being a steady-state problem, as it has previously been discussed, the arc column undergoes a continuous process of deformation and collapse, allowing it to move axially as well as azimuthally within the field coil

No abstract available

No abstract available