Bundled conductors for 13,800V overhead service

[adesmond01]

I need to run a new 13.8kV / 3000A feederline between two substations in an industrial plant. This feeder would be approximately 280 meters in length. There are several roadway crossings obstructing the route of this new feeder, making an underground conduit bank quite costly. If I were to go with an overhead distribution line, I would use 3 or 4 parallel conductors per phase with the largest ACSR wire available to give me ~ 3,000 amps. Has anyone ever seen this done? My understanding is this would be quite a unique design.

 

[ron]

Would you be triplexing the conductors and avoiding mutual heating from one paralleled set to the other? Follow NEC-2023 Table 315.60(C)(2) (Ampacities of Insulated Single Aluminum Conductor Cables Triplexed in Air) for ampacity.

 

[electrofelon]

I need to run a new 13.8kV / 3000A feederline between two substations in an industrial plant. This feeder would be approximately 280 meters in length. There are several roadway crossings obstructing the route of this new feeder, making an underground conduit bank quite costly. If I were to go with an overhead distribution line, I would use 3 or 4 parallel conductors per phase with the largest ACSR wire available to give me ~ 3,000 amps. Has anyone ever seen this done? My understanding is this would be quite a unique design.

Been a few months since I've done a 13.8kv 3000A feeder

 

[Jpflex]

Would you be triplexing the conductors and avoiding mutual heating from one paralleled set to the other? Follow NEC-2023 Table 315.60(C)(2) (Ampacities of Insulated Single Aluminum Conductor Cables Triplexed in Air) for ampacity.

I believe it’s not legal but my boss ordered triplexed 2/0 AWG Aluminum cables for underground feeders to terminate into an indoor 200 ampere single phase sub panel for a kitchen at a mine site. I would have gone 3/0 AWG non aluminum but copper and a different wiring method.

Regarding this post why so many amperes in the k range are we supplying a town lol. If you went under roads you would dig 24” minimum?

 

[synchro]

You usually see bundled ACSR cables with spacers at 230kV or above to reduce the voltage gradient of the surrounding electric field that causes corona discharges to occur.

Such spaced conductors also increase the effective diameter of the conductors in the generation of surrounding magnetic fields. This then increases the ratio of the effective conductor diameter to the distance to conductors on other phases, and so it therefore reduces the conductors' inductive reactance. That could be important at 3000A, but with the relatively short length of the run at 13.8kV it may not have much impact.

That many of the largest ACSR cables you can get is going to be very heavy, and so the support structures could be a challenge.

Would these roadway crossings be within the area owned by the plant? If so, could there be fixed support structures for raceways that pass over the roadways, but except for this there would be MV cables underground?