Sadegh Rahimi - University of Tehran
Asghar Bagherpour - University of Tehran
Ali Asghar Razi-Kazemi - K. N. Toosi University ofTechnology
Kaveh Niayesh - Norwegian University of Science andTechnology (NTNU)

Circuit breaker (CB) as the critical part of theprotection system, is used to isolate power system during faults.Electric power system blackouts and equipment damage mayoccur if a CB fails to operate due to failure in its interruptionchamber. Arc contacts are the most important part of theinterruption chamber therefore, condition assessment of theseparts are necessary. In this paper, a noninvasive method has beenproposed to measure the length of the arc contacts throughmonitoring of the delay in the drop voltage rise across the CBterminals during opening process. The proposed method hasbeen verified through experiments conducted on a real SF۶ CB.

Interruption chamber, arc contact, conditionassessment, delay measurement.