Appendix B says to use both synoptic and downdraft for region III. How do you apply this? Does this mean do 2 calculations for every line and use the worst case for your design? I'd appreciated hearing any thoughts on this.
Downdraft always gives a larger value for SRF (see graph) so do you...
Thanks engratcorner. Let's say you are in the heavy loading zone. Would you examine pole loading under the heavy load case, and also under a no wind case?
jghrist, thanks for your comments. It is not only when there is a deviation at a pole. If the spans lengths are not the same, even if the tension is, the worst case pole load will probably not occur when the wind is perpendicular to the line. Other software such as Poles 'n' Wires makes...
Yes I know wind can blow from any direction, hence the provision in that standard. Other standards say the same thing - reduce wind according to the angle between the wind and the line. Other overhead software like Poles 'n' Wires does allow for the angle of wind to line, but I can't seen any...
When doing a pole load calculation (ie nett load on pole due to conductor loads) what are common load cases you'd look at? eg no wind @ 60deg, wind/ice @ 0 deg etc?
Thanks.
NESC 252B.3 indicates you should reduce the wind load on a power line due to the angle of the wind to line. sag10 has no place to allow for that wind angle. Is this something to be concerned about? Thanks.
NESC 252B.3 says wind load on a line should be reduced due to the angle of wind to line. sag10 has no provision for allowing for angle of wind to line. It is something to be concerned about? Thanks.
