Spacing between multiple overhead lines

[ukgraduate]

Hello,

I am working on a project where we need multiple overhead circuits running in parallel. On each pole there will be 2 circuits (one on either side of the pole). Further to this we need 4 powerlines running in parallel for approx 800m.

I have searched everywhere for rules and standards or engineering advice on what the separation between poles should be but cannot find anything. I have the separation between pole and vegetation, house, personell etc etc.

But I do not know if there is some guidelines of ditance between parallel powerline poles.


Thanks UKgrad

 

[Desrod2]

There are technical separation requirements and practical requirements. Minimal distance will be the one you have between your circuit on a single pole. In practice, depending on work methods you might want to have enough room to put boom truck to work on your lines so the practical distance will be greater since you have to factor clearing between live line and you equipment and road to bring the truck on location.

Utilities should have standards for that. Ask colleagues.

 

[bacon4life]

In the USA, the National Electric Safety Code (NESC) Rule 235 gives minimum distances between adjacent circuits, with distances depending on whether the circuits are on the same or different structures. The NESC specifies the minimum safe distance, the prudent design distances will be much larger.

 

[rterickson]

Your transmission planners will tell you that if you place the lines close enough together to be considered on a "common corridor", your system will need to be able to survive the simultaneous outage of all circuits.

 

[ukgraduate]

Thanks for the feedback.

There is nobody at my workplace that can help on this. I have read NESC standard and its talking in mm. As Desrod 22 said I would have thought you need space for a boom truck. I was thinking of allowing 10m between powerlines, but I am not sure if this is reasonable?

Does anyone have any documents or experience based on utilities or other designs?

Is not inductive coupling an issue? Probably not for such a short distance <1km.

Thanks

 

[ukgraduate]

Bump

 

[Padlock01]

One should take into consideration the height of a pole especially in the event of a suspension pole falling over
my rule of thumb is on say 13 metre pole 2metre in the ground 11metre above so clearance of adjacent line 11 metre.
Regards

 

[lookintomyeyes]

In Canada, we use CSA C22.3. Similar to NESC, it's spacing requirements are quite minimal.

In my utility, we consider things such as:
- allow conductors of one tower to swing towards conductors of an adjacent line (which for conservatism, is assumed at rest). Ensure you have switching surge and/or power frequency clearance between the lines.
- consider maintenance requirements. Do you need space for a boom struck, crane, helicopter, etc? Do you require helicopter landing pads? Is there space for stringing equipment to work, or will you pay compensation to landowners for damages?
- if guyed structures, ensure you have sufficient clearance to the guys. Also, ensure guys will not be too close together - or you may affect the bearing capacity of the soil.
- Do you need to consider fall-over of one tower, into the other lines? Reliability requirements may require this, many may not.

Hope that gives you a few ideas of what to consider!