Hi all,
I am haven trouble with a question to do with solving the Sag and Slack of a transmission line, I have been starting at this for a while now without any luck.The question is
Using a level-span catenary model, calculate the sag and slack for a 335-m span of ACSR cable having a cable mass per unit length of 1.63 kg / m and a diameter of 2.86 cm.
The load on the cable consists of (i) ice with a uniformly distributed radial thickness of 0.965 cm and (ii) a constant horizontal wind pressure of 383 Pa of total projected area. Take the breaking tension for the cable as 133 kN and use a safety factor of 3.
Take the density of ice as \(915 kg.m^-3\) and gravitational acceleration constant as \(9.81 m.s^-2\)
Neglect thermal and elongation effects.
Span \(S = 335m\)
Mass \(M = 1.63 kg/m\)
diameter \(d = 2.86cm\)
ice radius thickness \(irt = 0.965 cm \)
horizontal wind pressure \(hwp = 383Pa\)
breaking tension \(br = 133kN \)
density of ice \( id = 915 kg.m^-3\)
gravity \(g = 9.81 m.s^-2\)
So I have found that the effects of Ice and Wind loading is
Xsectional area of ice
\(Ai = pi*irt(d+irt) = 1.16*10^-3 m^3\)
Weight of ice per unit lenght of cable
\(Wi = Ai*id*g =10.409 kg\)
projected area per unit lenght of ice covered cable
\(ai=d+2*irt=0.048\)
Horizontal wind force of ice covered cable
\(Fw = hwp*ai=18.346 \)
Resultant force due to wind and ice
\( Fwi = (\sqrt(Fw^2)+\sqrt(M*g+Wi)^2)=32.148\)
Now this is where I am stuck as I need to calculate Sag and slack. Am I on the right path or is there another way I should be solving this??
Any guidance would be a great help
I am haven trouble with a question to do with solving the Sag and Slack of a transmission line, I have been starting at this for a while now without any luck.The question is
Using a level-span catenary model, calculate the sag and slack for a 335-m span of ACSR cable having a cable mass per unit length of 1.63 kg / m and a diameter of 2.86 cm.
The load on the cable consists of (i) ice with a uniformly distributed radial thickness of 0.965 cm and (ii) a constant horizontal wind pressure of 383 Pa of total projected area. Take the breaking tension for the cable as 133 kN and use a safety factor of 3.
Take the density of ice as \(915 kg.m^-3\) and gravitational acceleration constant as \(9.81 m.s^-2\)
Neglect thermal and elongation effects.
Span \(S = 335m\)
Mass \(M = 1.63 kg/m\)
diameter \(d = 2.86cm\)
ice radius thickness \(irt = 0.965 cm \)
horizontal wind pressure \(hwp = 383Pa\)
breaking tension \(br = 133kN \)
density of ice \( id = 915 kg.m^-3\)
gravity \(g = 9.81 m.s^-2\)
So I have found that the effects of Ice and Wind loading is
Xsectional area of ice
\(Ai = pi*irt(d+irt) = 1.16*10^-3 m^3\)
Weight of ice per unit lenght of cable
\(Wi = Ai*id*g =10.409 kg\)
projected area per unit lenght of ice covered cable
\(ai=d+2*irt=0.048\)
Horizontal wind force of ice covered cable
\(Fw = hwp*ai=18.346 \)
Resultant force due to wind and ice
\( Fwi = (\sqrt(Fw^2)+\sqrt(M*g+Wi)^2)=32.148\)
Now this is where I am stuck as I need to calculate Sag and slack. Am I on the right path or is there another way I should be solving this??
Any guidance would be a great help