The detection system in substation of medium voltage overhead line can mostly detect only low impedance fault, neither broken conductor on the source side with high impedance, nor broken conductor on the load side with even direct to ground. This paper presents novel method to characterize such faults using time shifting in 3 phase line current. It can be applied, however, in parallel with the conventional over-current relays. The experimental results show that this method can well detect those occurrence independent on line distance from substation with radial outgoing feeders.