We should consider the following points when choosing OPGW cable:

1. It is necessary to meet the requirements of meteorological conditions, the requirements of its own tensile strength and the requirements of the allowable design load of the tower.

2. The main technical data to be considered in the design of OPGW are: optical fiber type, optical fiber core number, optical cable diameter, optical cable cross-sectional area, optical cable unit mass, ultimate tensile strength, short-circuit current, DC resistance, elastic modulus, thermal expansion coefficient, Annual average operating stress, minimum bending diameter, maximum coil length, etc.

3. Under the condition that the ambient temperature is +15℃, there is no ice and no wind, and the sag of another ground wire is consistent, OPGW optical cable can be selected.

4. OPGW allows the determination of short-circuit current. First determine the equivalent time of short-circuit current. Generally, when the short-circuit current of a 220kV line is large, the equivalent time of fault current can be considered as 0.3s. According to the short-circuit current provided by the system, the total short-circuit current of the line entering the ground is calculated, and the short-circuit thermal stability value of the OPGW and another ground wire is checked at the outlet of the substation by calculating the short-circuit current distribution between the OPGW and another ground wire. When a single-phase short circuit occurs on the line, a brief large current appears on the overhead ground wire, and the heat generated by the current increases the temperature of the optical cable and the shunt wire. Because of the short duration of the current, the heat does not dissipate to the surrounding ring