AbstractsEngineering
Modelling of breaking arcs when they are extinguished by current zero-crossings
| Institution: | Uppsala University |
|---|---|
| Department: | |
| Year: | 2014 |
| Keywords: | Engineering and Technology; Electrical Engineering, Electronic Engineering, Information Engineering; Other Electrical Engineering, Electronic Engineering, Information Engineering; Teknik och teknologier; Elektroteknik och elektronik; Annan elektroteknik och elektronik; Civilingenjörsprogrammet i teknisk fysik med materialvetenskap; Master Programme in Materials Engineering |
| Record ID: | 1338780 |
| Full text PDF: | http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226204 |
Abstract
When breaking large currents in switching devices, arcs are created, which continue to carry the current. It is desirable to extinguish these in order to break the current. In this master thesis a model of the arcs behavior during current zero-crossings was made and put into a module, which is to be used when simulating electrical AC arcs. The module will be used when designing switches, e.g. contactors. When the current falls to 0 A there is a race between the transient recovery voltage and the dielectric strength, which determines if the arc will extinguish or restrike. The arc is extinguished if the dielectric strength is greater than the transient recovery voltage through the whole cycle. The transient recovery voltage is only dependent on the circuit used. The dielectric strength was found to mainly depend on the arc current, gap length and contact material. A model of the dielectric strength was made to determine if the arc will restrike or not.
