transmission line construction

The question is about where you want to break down. Now, you desire a complete professional education here about this, that or something else?

Its is not like that I am in this field of about 17 years in field experience. Just I am checking some documents so I want to ensure about theory, if you know and willing to explain give details otherwise no problem.

Thanks & Regards,

R.Vijayan.

It's a bit more involved and depends a great deal upon the line location and loading but the weight span limit is well known and universal.

For a given span length, as the conductor sag is increased, the line tension at the tower or support structure will decrease until a point is reached at which the tension at the supports will begin to increase due to the weight of the conductor. This point occurs when the sag is approximately 1/3 times the span length and that relationship can be expressed as Lmax = 1.33 (T/wc) where: Lmax = maximum span length (meters or feet), T = the resultant tension at the support (Newtons or pounds force) and wc = weight of the conductor (kilograms or pounds).

Thank you very much for the explanations, but I want to know about wind span and weight span limitations.

Thanks & Regards,

R.Vijayan

Thank you very for clear explanations.

Thanks & Regards,

R.vijayan

On a transmission line conductor wind acts at 90 deg to line direction or perpendicular to the route.The wt acts down wards.In a span between two towers the total wind force on conductor is shared by the two towers.So wind span for a tower is sum of50% of the two spans on its either side .The sag point is in the middle of the span between two towers on horizontal ground.The weight of the conductors is shared by the two towers on either side .The wt span on a tower is sum of 50% of the distance from sag to the tower either side.In a plain land weight and wind spans are equal.on a hilly terrain where one tower at a higher level such that the sag poit of the conductor (projected )goes beyond the lower tower.In such case it is a negative wt span.For example let us consider four towers A, B, C, D.A,B, Care on level ground.D is on top of a hill.If span between A-B is 400 M B-C300 M C-D 500M.The wt span on B will be 350M.On c if we assume sag point of the conductor goes beyond towerc and projected length is 100M.Weight span on C is 150-100=50M.Wind span will be 400MThe concept of negative weight span comes in hilly terrains.It simply means instead of a down ward force acting on the tower due wt.of conductors on either sidethere is an upthrust and foundation has to be made suitably.Of course if next tower location Say, E will determinie wt span on D.We have not taken ICE loading which is common in cold countries and wind acting on projected area can be severe.Wind span matters a lot during river crossings or near coast.Hope could clarify.

Thank you very much sir, I had clarified now better.

Thanks & Regards,

R.Vijayan