Correct Answer - Option 4 : D = d + 2t
The formation of ice on overhead conductors may take several physical forms (glaze ice, rime ice, or wet snow). The impact of lower density ice formation is usually considered in the design of line sections at high altitudes.
The formation of ice on overhead conductors has the following influence on line design:
- Ice loads determine the maximum vertical conductor loads that structures and foundations must withstand.
- In combination with simultaneous wind loads, ice loads also determine the maximum transverse loads on structures
- In regions of heavy ice loads, the maximum sags and the permanent increase in sag with time (the difference between initial and final sags) may be due to ice loadings.
The overall diameter of the ice-covered conductor becomes,
D = d + 2t
Where d is the diameter of an overhead transmission line conductor and t is the thickness of the ice-covered over it.