Fault location algorithm for cross-bonded cables using the singularity of the sheath impedance matrix

This paper proposes a fault location algorithm for cross-bonded cables. The algorithm uses nonlinear equations that describe the voltage drops between both ends of core conductors and sheaths in terms of the phase voltages and currents of both the local and remote ends. Arranging these equations about the sheath currents yields a sheath impedance matrix, which is singular independently of the fault distance. Due to this singularity, the equations have no solution or an infinite number of solutions. The proposed algorithm finds the condition for which a solution to the equations exists. Since the equation of the condition is linear and explicit, the fault location can be found easily. Test results indicate that the algorithm accurately estimates the fault distance regardless of fault impedance, fault type, and fault section.