Overloading distribution O/H line ?

[sparky1976]

All,

I have 5 kilometers 33 kV overhead line, with hawk conductor.

Now reach its ampacity limit which the table says 420 amperes. Its happen statistically once per Hour for a month (caused by addtional motors that start periodically), sometimes get to 430 amperes.

What is going to happen or make significant damage to the line in the long term and short term if I wait for 1 years.

Some of I can think is increase in voltege loss, heat on the conductor, but I'm not sure if this heat will damage clamps or connection very fast.

Please advise me so I have more ammo when I ask for second O/H line to management.

Thanks
Pitat

 

[jghrist]

It is usually a bad idea to operate a distribution line at peak loads near the ampacity of the conductor. The cost of losses usually makes it uneconomical. Voltage drop may be excessive. There will be more sag and ground clearances may be a problem.

 

[MikeDB]

Don't know what table you are using, but ALCOA and RUS tables indicate higher current ratings. For 75C conductor temperature and 25C ambient temperature, these show maximum currents from 470 to 700+ amps depending on wind and sun conditions. The 75C limit is well below the annealing temperature (about 93C) and some companies might use a limit of 100C or more for emergencies. So if you have ground clearance, for conductor sag at that temp., there should be no problems. As metioned before, that may not be economical due to line loss.