To calculate the efficiency of the cable protection of overhead lines (OL), a formula, common for OLs of all voltage classes, has been offered. The formula takes account of the main parameters, affecting a break: working voltage, the angle between the cable and the conductor on the support, the shift of the cable and the conductor in the horizontal plane, the capacitance of the conductor. In
... [Show full abstract] estimating the probability of a lightning break in a variety of 330-765 kV OLs, the discrepancy between calculated and operational values of lightning-surge proofness did not exceed±10%.