Road size/radius inside substation

[atrizzy]

Does anyone have a quick/dirty guide relating required road size/radius to the equipment inside a substation?
I've used 6m/25m width/radius in the past for stations containing very large transformers, but presumably this can be reduced for simple switchyards and the like.

Thanks!

 

[cuky2000]

Turn radii for the internal roadway are important for moving large equipment. This should be designed to allow to move equipment inside the substation without an outage or major rework.

In the US, for new important substations usually is designed to accommodate a 73.5 ft (22.40 m) trailer WB-67 or largest equipment. For curves and turns should wider to accommodate the long lengths of the trailer that are needed to haul power transformers, reactors, etc. The following are the minimum recommended general criteria:
a) 14 ft (4.3 m) minimum to avoid back out.
b) 56 ft (17 m) for 90^o turn
c) 71 ft (21.6 m) to account for hauling equipment.

The trailer also should have the ability to travel along the perimeter and any primary roadway necessary for future structure or equipment deliveries. To facilitate the design and construction of the roadways, It is recommended to use of the trailer turning template to reflect that on the civil package.

 

[atrizzy]

Thanks cuky,

In this case we're not dealing with a major substation. But I think you're right, I'll just identify the truck required for installation and go from there using trailer turning template methodology.

Appreciate the response.

 

[bacon4life]

If there are gates on opposite sides of the substation, turning radius for trailer may not be necessary. At smaller substations we require turning radius for crew trucks but accept that we may have to back in semi trailers. In addition to turning radii, there are some additional clearances that might be needed:
1) The ability for standard crew trucks and our small bucket trucks to maintain 10+ feet of radial clearance from the top of the truck to any energized part.
2) Placement locations of oil tankers & oil processing trailer during transformer processing.
3) Access for a 250T hydralic crane for setting the transformer & switchgear, along with a location for the delivery truck to park. One of these might be outside the substation fence if you know for sure the area will remain accessable for the life of the substation.

 

[cuky2000]

Be aware that the internal access road design could be impacted by the hardening requirement mandated by the compliance with the NERC-CIP (North American Electric Reliability Corporation for critical infrastructure protection). Depending upon the criticality of the substation, the NERC-CIP could mandate restricting access with motorized vehicular gates, barriers and even ballistic rated walls to mitigate the vulnerability of transformer and other critical assets. This may impact the roadway design reducing the gates and restricting the adjacent, entrance and somehow the internal road design.