Transmission Line Field Acceptance / Performance Testing

[briand2]

My experience extends only to 11kV within buildings, so apologies for what may be a trivial question...
Once a new transmission line (say 400kV) has been constructed and commissioned, are any tests carried out to check its real performance / ampacity. (I'm aware of the type testing of the cables, etc before construction, but what if, for some reason, the completed construction does not perform, i.e. it gets too hot / sags too much / impedance too high, etc).

Thank you in advance for your help.

Brian

 

[marks1080]

I don't know if i will of any real help as I am electrical not mechanical...

I can't see any point in stressing a new line to its extreme limits in testing. I would think material characteristics (regarding line sag, etc...) are fairly standards and one can extrapolate on information to an acceptably accurate degree.

Taking thermal readings on the line during normal loadings might help give you an idea if there are 'bad spots' in the cable - these spots should be hotter than normal.

There are various other considerations might be needed based on whatever specific situation you are dealing with....

For example: Are there other transmission lines built in that corridor? Is there a possibility for ferroresonances? Could the circuit become electrically coupled with another circuit?

All of these things should be consdiered during the initial design. I do not know if they are normally tested for after construction - my gut feeling would be to say 'no'...