Summary

Recommendation ITU-T K.101 contains the calculation procedure for the shielding factors used in Recommendations ITU‑T K.46, ITU-T K.47, ITU-T K.56 and ITU-T K.97, and it is intended to:

1)          provide the rationale for the shielding factor approximate formulas or values contained in the aforementioned Recommendations;

2)          allow a more precise calculation of the shielding factors, by using the equations provided in this Recommendation.

The shielding factors considered in this Recommendation refer to:

•            that of the lightning current distribution in a telecommunication tower, i.e., that of the tower (α_T) as per Recommendations ITU‑T K.56 and ITU-T K.97;

•            that of the lightning current distribution among several conductors placed in a cable ladder, i.e., that of the feeder tray (α_F) as per Recommendations ITU‑T K.56 and ITU-T K.97;

•            that provided by the cable tray (β) as per Recommendation ITU‑T K.56;

•            that of parallel conductors (η) as per Recommendation ITU‑T K.47;

•            that of refraction (δ) due to the earthing connection of a telecommunication cable, as per Recommendation ITU‑T K.46;

•            that provided by a telecommunication cable having a metallic sheath (shield) (η) as per Recommendation ITU‑T K.46.