Allowable horizontal distance from the substation fence

[tctctraining]

We are designing a 230kV substation and wondering if there are any code/standard requirements in Canada to provide certain horizontal distance from de-energized parts a 230kV substation equipment ( such as A-Frame) to the substation fence?

 

[rterickson]

From a table of typical electrical clearances that I have (source unknown):

"Minimum Distance at Perimeter Fence, Metal-to-Fence Horizontal Distance" 19'-0" at 242kV

"Based on IEEE 1119-1988, "IEEE Guide for Fence Safety Clearances in Electric-Supply Stations""

 

[racookpe1978]

Many switchyards put at least one of their maintenace or "high-height" access roads right up against the fence specifically to take advantage of this "requirement" - thus, when I need to back a crane back through the switchyard to do repairs or replace equipment (not a transformer, but something else) I can get that crane or truck much easier "around" the switch yard next to the fence than try to go right through the middle.

the high volt cables are also higher up (going towards the first tower) to the edge of the yard, and not as high near the middle where the cutouts are.

 

[bacon4life]

Not sure about Canada, but no requirements I know of in the USA. We typically have an access road between the fence and any equipment. However, we sometimes have the incoming transmission pole just inside or just outside the fence. Thus we use the vertical & radial clearance requirements to live parts at the top of the pole and no horizontal clearance to grounded parts. We also have many structures such as control buildings, lighting standards and communication towers near fences.