MV OHL 1

[vavanapoly]

hi every one
if I have a 13.8 kv MV OHL
the total length of it is 110 km
and after 60 km the voltage droped from 13.8kv to 11kv
is it possible to install transformers that its primary voltage is 11kv after 65km?

 

[davidbeach]

You need a transformer with an automatic load tap changer. Shunt capacitors at two or three points along the line could help considerably.

 

[jghrist]

The problem is that the voltage drop will only be at heavy load. At light load, the voltage drop will be low and the 11 kV transformers will have overvoltage.

You could add shunt capacitors as suggested by davidbeach or use voltage regulators on the line at the point where the voltage drop is too high at heavy load.

110 km is very long for a MV line. Besides unacceptable voltage drop, your line losses will be very high.

 

[wareagle]

THIS WILL TAKE CARE OF YOUR PROBLEM. INSTALL THEM AT THE POINT WHERE THE VOLTAGE DROP NEEDS CORRECTION. tHREE CAN BE POLE MOUNTED ON A PLATFORM.

http://www.geindustrial.com/publibrary/checkout/Brochures|DEA270|PDF

 

[alehman]

Capacitors with automatic voltage control could be useful as well.

 

[davidbeach]

Yes, voltage regulators. I started to say that in my first post and then apparently misread the OP and thought it was a higher voltage. 110km is way too long for 13.8kV, probably about 5 times too long. A much higher voltage will provide far better results. But if it has to be that long at that voltage you probably need a combination of regulators and capacitors.

Place caps as/where needed to maintain an approximately flat voltage profile at no load. Then install voltage regulators as/where needed to maintain an acceptable voltage profile at full load. If you have no tapped loads you can get away with a less flat voltage profile; if you have tapped loads all along the line you will need more control points.