Modellierung des Plasmas im Vakuum-Leistungsschalter unter Berücksichtigung axialer Magnetfelder

The main task of vacuum circuit breakers is the switching of short circuit currents, which can reach values of about 50 kA in medium voltage systems. In the medium voltage area the vacuum technique is the dominant switching principle and is mostly used worldwide whereas the market share amounts 60 %. Vacuum circuit breakers are typically used up to a voltage of 36 kV and a short circuit current of 50 kV. The substantial switching element is the lightning arc which forms when separating the contacts. The constriction of this arc at higher currents because of the pinch effect leads to a strong erosion of material on the contact surfaces, especially on the anode surface, and consequently decreases the switching capability. The positive effect of axial magnetic field (AMF) contacts on the switching behaviour is based on the stabilisation of the vacuum arc by the axial magnetic field, which is produced by the current flowing through the contacts. This concept does not only enable the switching of higher currents. It also allows the application of vacuum circuit breakers at higher voltages because of the reduced erosion on the contact surface. Within the scope of this work the arc plasma between AMF contacts is modelled by a simulation program and hence the influence of axial magnetic fields on the discharge of high current vacuum arcs is studied. The main intentions are the determination of the important plasma parameters such as charge density, current density and internal fields, the investigation of the forming time of the anode spots and an estimation of the influencing variables. This work aims to point out an alternative to the widely used fluid models, which are based on a local thermodynamic equilibrium, by a kinetic modelling of the arc plasma and to present possibilities for its solution. For this reason, a substantial contribution to the characterisation of the switching behaviour of AMF-contacts is done by this project.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2003

Author dc:creator

• Jenkes-Botterweck, Kerstin

Contributors dc:contributor

• Schnettler, Armin

• info:eu-repo/classification/ddc/530
• Physik
• Vakuum-Leistungsschalter
• Plasma

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-120673%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:58842