Influence of earthing conductors on current reduction factor of a distribution cable laid in high resistivity soil

Various types of system circuit faults are possible. The most common is the phase-earth fault. During this fault, currents flow through earthing grids as well as through the earth. These currents are the consequence of electromagnetic coupling of conductors and earthing grid potentials and can be presented by current reduction factor. When earthing conductors are laid together with cables, the current reduction factor is very difficult to define. In this paper a mathematical determination model of current reduction factor is presented for the cable and earthing conductors laid in the same trench. Influence of both electromagnetic characteristics and earthing conductor geometrical characteristics as well as influence of geophysical features on the current reduction factor is analyzed in this paper.