Based on discharge mechanism of the pantograph and catenary

extract the characteristic quantity—（ 250 ±10） nm wave band ultraviolet light of arcing discharge occurring

as online testing goals

and develops a kind of non-contact UV detection system for pantograph-catenary arcing.Detect the arc phenomenon for Guangzhou Metro Line 2 by this detection system

screen the tendentious signal of current by the way of empirical mode decomposition method and analyze the processed current signal

results show that the arcing causes the 0

50 Hz harmonic amplitude in traction current increased significantly.