Conductor blowout - wind loaded sag or not?

[designdraft]

When calculating conductor blowout, do you use sag calculated with wind loading, or without? The literature seems undecided.

"Since the wind-displaced sag in the conductor is affected by the both the wind and weight forces, a resultant force can be calculated and used as a substitute for conductor weight in the sag and tension calculations to obtain the sag along the swing angle under wind loading conditions." Calculation of Horizontal Displacement of Conductors, 1994, A Clapp

"The effective conductor dead weight results from the weight span without considering the increase in tension due to wind action." Overhead Power Lines, 2014, Keissling et al.

Any thoughts?

Thanks.

 

[jghrist]

Use the conductor weight of the weight span for the vertical force, the wind force on wind span for the horizontal wind force, and the resultant of the horizontal tension of the ruling span for the horizontal tension force.

 

[stevenal]

I've noticed the definition of sag is flexible. Sometimes it's the vertical component, sometimes the resultant. Make sure you understand which definition applies.

 

[KillBill7]

It makes sense to the use the resultant weight as that would include the the horizontal component of weight due to wind load. With electrical clearances like blow out, it's not a bad idea to stay on the conservative side.

 

[designdraft]

Thanks for your responses. Yes, that all makes sense.

Graham Willis
ipowermation.com