Bus Support for IPS

[corbin801]

I was wondering if the connection shown in the drawing below,(two welded four hole connectors) would be considered a suitable bus support for the smaller IPS span? Larger Aluminum IPS span is 17” the smaller span is 12.5’. I’ve only considered insulators, S.A.’s, switches, bushings… as sufficient support for an IPS run. I’ve never seen this done.\

Thanks,

 

[jghrist]

You could use a weldment tee connector. See

http://www.acasolutions.com/resource_center/online_catalogs/pdfs/Substation-230kV.pdf

page 38. The only problem is figuring out forces during a fault. It isn't a straight forward calculation because of the configuration.

I assume you mean the the larger span is 17' not 17".

 

[corbin801]

Yeah it's 17'. A bolted tee connector or a welded connector would work. Just was wondering if anyone had worked the numbers, or could send me in the direction of some standard that would explain this connection in the terms of IPS sizing.

 

[jghrist]

Here's an attempt I made (years ago and not recently reviewed) to calculate forces on an L shaped bus section.

 

[jmmee97]

Corbin801,
I agree with you. I don't like supporting a piece of IPS with another piece of IPS that, in turn, is being supported by two switches. I would modify the structure to include a bus insulator either supported from the vertical disconnect switch steel support or add a cross member to the 'A' frame structure to mount the insulator to. My opinion...

 

[racobb]

Agreed....Support it well and make sure you allow for expansion and contraction.

Alan

 

[stevenal]

A rough rule of thumb we use, assuming the ampacity and short circuit strength is sufficient; 1" spans 10' horizontally, 2" spans 20', etc. This will avoid excessive sag so it'll look good.

Expansion is addressed by the two bends.

The longer vertical span would be at more risk of deformation from a short circuit than the short one.