To meet the needs of rapid and reliable short-circuit fault protection and location in urban rail DC traction networks

this paper proposes a method for short-circuit fault protection and location based on multi-source characteristic harmonics. The method and implementation process are outlined according to the characteristics of short-circuit faults involving multi-source characteristic harmonics. Research results show that no malfunctions occur in the protective devices of operating urban rail vehicles during startup procedures. When metallic short-circuit faults occur

the device triggers a response within 0.1 s following the onset of the fault. In scenarios where urban rail vehicles are not in operation

short-circuit faults do not see fault type judgment affected by deviations between calculated transition resistance values and set values

with the maximum deviation between calculated fault locations and set values reaching 12.10 m. Fault detection is conducted in segments of 300 m

with a maximum error rate of 4.03%5%. The research results provide a reference for improving the reliability of short-circuit fault protection and location in urban rail DC traction networks.