MikeMillerGIS commented 5 years ago

There are two main kinds of Underground Junction Boxes. There is surface mounted and subsurface mounted.

[ ] Surface mounted medium voltage junction box/cabinet
[ ] Subsurface medium voltage junction box

The surface mounted medium voltage junction box or cabinet is a cabinet that contains a junction bar with bushings that elbows connect to, as shown in this picture

The subsurface medium voltage junction box is typically a concrete box, possible precast, with a junction bar that has several bushings and medium voltage elbows connected to these bushing, as shown in this picture.

MichaelZeiler commented 5 years ago

Underground Junction Box-01 @jalsup , I used to think junction boxes were simple ;) After your comments, I'll add the key. And, I think the only difference between this and the pad-mounted junction box is to replace the vault with a pad. At first, I was modeling three busbars for each phase, but decided one three-phase busbar was more consistent with our other models.

jalsup commented 5 years ago

Ha, nothing is simple! Actually we should use a point feature, one for each phase. The feature is a Device and the Asset Group is Medium Voltage Elbow and the Asset Type is "Load Break Feedthru" and this is a picture of one from Hubbell. It can have two, three or four bushings. So, I would suggest dropping the busbar and using the point feature, one per phase. These are not typically tracked with an asset id, but they are material and I know Sempra tracks their locations and models.

MichaelZeiler commented 5 years ago

@jalsup Ok, looking at the photo above and the photo of the vault, it seems like this is the model.

Question: do the load break feedthrus break power selectively at each bushing? Or open/close all bushings at once? If they break power at each bushing, we need terminals for this device and a separate subtype for 2/3/4 bushings because they would require distinct terminal path configurations for 2/3/4 bushings. If they break power to all bushings at once, I'm not sure if we need terminals. What do you think?

There is a pad-mounted junction box a block away from me, I'll take a photo of it next time I'm out.

Also, are there any differences between the pad-mount and vault junction boxes besides the structure they attach to?

Underground Junction Box

jalsup commented 5 years ago

what happened to the other elbows? Those need to stay. The Elbows connect to the Feed Thru. there are no switches, etc inside the Feed Thru. It is basically a bus with bushings. The Loadbreak is that is has arching terminals that the arc will jump to when the elbow is opened. We don't need terminals on these.

MichaelZeiler commented 5 years ago

Underground Three Phase Junction Box-01

Ok, here are my revisions. What threw me was the name 'load break feedthrus' which implied they are breaking devices. I see now how the elbows connect into the bushings of the load break feedthrus.

One more thing still puzzles me: I see that the junction box is actually a structure junction in our data model, not an assembly. Correct me if I'm wrong, but can we really establish a structural attachment between two structure junctions? I was unaware that we could.

Once you say this is good, I'll send the PDF to the repo

pLeBlanc93 commented 5 years ago

@MichaelZeiler everything except DomainLine and StructureLine can be attached to StructureJunction

MichaelZeiler commented 5 years ago

Thanks @pLeBlanc93

jalsup commented 5 years ago

this looks good. I will actually draw this up in the data today so we can see how it looks in their.

MichaelZeiler commented 5 years ago

@jalsup The variation of this would be a pad-mounted junction box. But it would be trivial if the only change was substituting a vault for a pad. To make a variation interesting, how about a single-phase or V-phase pad mounted junction box?

jalsup commented 5 years ago

single phase would be good and easy. Let's use that for the subsurface junction box and three phase with the cabinet.

MichaelZeiler commented 5 years ago

Underground Single Phase Junction Box The single phase case with vault. I (trivially) changed the three phase case to a pad.

MikeMillerGIS commented 5 years ago

Isn;t the vault a container?

jalsup commented 5 years ago

@MichaelZeiler The vault should be removed. The attachment points would be connected to the junction box. Also, we do not use Taps on underground. The eblows would be connected to the Line Ends. Given we are removing the taps, I don't think you need to bend the lines either.

jalsup commented 5 years ago

@MichaelZeiler We don't use Taps in underground, so remove those.
Don't bend the line. Connect the Elbows to the Line Ends Remove the vault.

MichaelZeiler commented 5 years ago

Underground Single Phase Junction Box

jalsup commented 5 years ago

That looks good to me! I Like it.

MikeMillerGIS commented 5 years ago

that is a nice drawing and really helps!

MichaelZeiler commented 5 years ago

Thanks, now I've made parallel changes to the three phase case. Question: how do we distinguish the pad case from the vault case now that those structures are gone? Is it an attribute on the junction box feature?

Pad Mounted Three Phase Junction Box-01

MichaelZeiler commented 5 years ago

When I mentioned during UN scrum that I was working on some configurations, Tom emailed me later asking to looking at some. I sent him the two junction box examples. He pointed out a couple of errors/simplifications: a structure junction cannot simultaneously be a container and structure to which attachments are made. It has to be one or the other. Also, he advocated for getting rid of line ends and attachments and simplify the configuration. Lastly, Tom was confused (as I was at first) by the name "load break feedthrus" as this name implies that this is a load-breaking device, which it is not, but an electrical junction. He recommended adding a small picture, so I took a photo and made a quick drawing of the thing. I'll start adding small drawings when relevant, this one took 10 minutes.

These are the revising drawings.

Underground Single Phase Junction Box-01

Underground Three Phase Junction Box

Tom's feedback is valuable, so I'll make a habit of sending him configurations as I work on them. I invited him again to join the repo, but he didn't bite

MikeMillerGIS commented 5 years ago

That is nice mike, we just need to make sure we are not using any copyrighted material. That is my concern.

pLeBlanc93 commented 5 years ago

You can hire my kids for the low low price of Pepperidge Farm Goldfish™️ to build some Lego®️ configurations.

MichaelZeiler commented 5 years ago

Yes Mike, that's my concern too, which is why I made a new drawing from scratch in Illustrator based on a photo. We are safe with that.

Speaking of lego, LeBlanc Enterprises, I'm making the Apollo Saturn V lego rocket now ;)

MichaelZeiler commented 5 years ago

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MichaelZeiler commented 5 years ago

Added pads

Underground Single Phase Junction Box Underground Three Phase Junction Box

jalsup commented 5 years ago

looks good, can you upload the file?

MichaelZeiler commented 5 years ago

Already submitted as part of pull request on April 23

Esri / utility-network-modeling

Underground Junction Box #110

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