Patent ID: 7514933

Claim:
A fault detecting device for locating a phase-to-earth fault in a three-phase electric line of an electric network, the fault detecting device being configured to: monitor current and voltage quantities of the three-phase electric line at a measuring point; detect a phase-to-earth fault on the three-phase electric line and a faulted phase of the three-phase electric line; calculate load-compensated zero and negative sequence currents by using a ratio of a total zero sequence admittance of the electric network and a zero sequence admittance of the electric network without the faulted electric line and by using a negative sequence current of the faulted phase and a zero sequence current; calculate a load-compensated phase voltage of the faulted phase by using the compensated zero sequence current; and calculate a distance between the measuring point and a point of fault using the compensated negative sequence current and the compensated phase voltage and an equation relating the current and voltage quantities to the distance.