Method to protect lines of two cables from single phase-to-earth fault

The method of protection against single phase-to-earth fault of the electric line of two cables based on measurement of current difference of zero-sequence in cables of this line has been developed. For this purpose, a simple method of zero-sequence current simulation in line of two cables, based on the conversion of an electrical network scheme to the design scheme and use of the Electronics Workbench general-circuit simulation system is offered. The paper reveals dependences of these currents and their difference from the location of a point of single phase-to-earth fault and sizes of capacity concerning the earth of all lines of a network except for the studied two-cable and offers schemes for implementation of the protection organization on this method and defined zone of its action.