Pipe in high voltage yard

[Jerry123]

Can someone please refresh my mind on why pipe is used for the conductor in high voltage yards and not cable.

 

[gordonl]

I would guess because it is self supporting with better cooling characteristics. (Still made of conducting material)

 

[jmmee97]

Also, you have to tension the cable to limit its sag in the station, which can increase the size of support structures.

 

[digitrex]

It is the "skin effect", i.e. more electrons are flowing nearer to the outer edge of a conductor rod.

Therefore for a same current rating of a conductor, it is more economical (less material used and less weight) to make the conductor hollow than a solid conductor.

 

[jbartos]

Comment: I concur with the above postings. Also, the tubular bus tends to be physically more manageable or routable than many smaller cables with insulation and many connections at various terminals (the larger cross-sectional area is required, which means more copper).

 

[mersin33]

Just an addition:

3000-A bus current is generally taken as the break-point for selecting tube bus vs flexible bus. In designs with 3000-A and above, tubular bus is generally cheaper.

 

[scottf]

It depends on the voltage level, but tube may have better corona/RIV performance than cable of an equal current rating. I believe this is based on the fact that tub generally has a larger OD than cable for equal ratings.