To ensure the staff safety under hot-line overhead transmission line (OTL) maintenance, as well as overhead ground-wire cable
(OGWC) insulation integrity maintaining, by the example of three-phase 750 kV OTL has been presented an algorithm for
calculation of voltages and electromotive forces (EMF) induced in this line’s OGWC by electric and magnetic fields (EF and MF)
generated by OTL phases’ voltages and currents. Algorithms for calculation of line-to-earth voltages distribution along grounded
at one end OGWC’ intervals have been given. It has been shown that the voltage induced at OGWC by EF of 750 kV OTL is much
less than the voltage induced by this OTL’s MF. For single-phase short circuits modes has been presented an algorithm for
selection of grounded at one end OGWC’ interval length by condition of respecting of voltage’s maximum permissible level on a
spark gap shunting OGWC’s insulator set.