Detection of down conductor faults in an overhead electrical power distribution system is extremely difficult by the conventional over current protection devices. This paper presents a new digital down conductor detection scheme which is based on the combination (AND logic) of the ratio of the negative sequence current to the positive sequence current and the value of under current during an actual down conductor condition. Real time implementation of the proposed scheme has been carried out on an existing Indian 11 kV, 3 Phase, 50 Hz power distribution system with the help of digital over current relay. At the end, a comparative evaluation of the proposed scheme with the scheme modeled in PSCAD/EMTDC software package is also presented. Both practical and simulation results indicate the effectiveness of the proposed scheme.
