Electric Utility Network Subtransmission and Substation Tiers

[EdwardBlair]

Hi -

We are starting discussion on out Utility Network model and are considering adding tiers for sub-transmission and substations.   The sub-transmission tier would hold equipment energized at 34.5kV, 25 kV and 23kV - which are distinct from both transmission and distribution tiers.   So we feel pretty safe there.   

But (we *think*) we also want a substation tier that encompasses equipment within the substation - with a subnetwork controller being one or more "injection points" on the high side of the sub.   Of course the substation has equipment energized at transmission, distribution and sub-transmission voltage levels.   So this would prevent the tiers from being in a consistent hierarchy -- for example sometimes sub-transmission will be on the "load" side of the sub and sometimes sub-transmission will be on the "feed" side of the sub.

Will we run into problems with this tier definition?   Has anyone configured tiers this way?   

Any pointers would be much appreciated.

Thx,

Ed

[gis_KIWI4]

@EdwardBlair - I am going to assume you are using a partitioned subnetwork here.
The lowest number indicates the highest tier. 

So it might look like 

Transmission Tier = 1
Sub-Transmission Tier = 2
Distribution Tier = 3

Tier Rank is quite important in UN. Ranks control the trace order of subnetworks from different tiers.

If I have understood you question correctly you want a substation Tier between Transmission and Subtransmission and between Subtransmission and Distribution Tier. 
So let's assume you introduced a substation Tier with rank 2. 

Transmission Tier = 1
Substation Tier = 2
Sub-Transmission Tier = 3
Substation Tier = 2
Distribution Tier = 5

This will mess up the flow and trace order.
A Tier can only belong to one rank.

You would want 2 substation Tiers - maybe shown below. 

Transmission Tier = 1
Transmission Substation Tier = 2
Sub-Transmission Tier = 3
Sub-Transmission Substation Tier = 4
Distribution Tier = 5
====================================================================

I would also consider the need for Substation Tier as a separate Tier unless you absolutely need it.
If the use case for a substation tier is to find what assets are within a substation - I would use connectivity/containment associations.

We have modelled ours like this. 
Blue lines = 33kV
Red lines = 11kV
But you will notice that the Subtransmission tier (pink hand drawn line) actually extends all the way to the circuit breakers i.e the subnetwork controller for the distribution tier (yellow hand drawn lines) 

[EdwardBlair]

Thanks much for the reply!  And for the great level of detail here.

Our immediate though for introducing a substation tier was as a means to extract substation internals to our ADMS.  Oracle NMS considers substations a distinct "partition" that we export substation internals (currently from an ArcGIS 10.x extractor process) using a query that returns features with a common "Sub FacilityID" field.  Going forward we thought we might replace this with a subnetwork trace from the "injection points" on the high side of the station.

Given the complexities described for substation tiers we may stick with our current logic of querying with a "Sub FacilityID" field.

Thanks again!

[gis_KIWI4]

@EdwardBlair  - I would also like to point out this community (if you don't know about it already) is much more active and you may get quicker turnaround for your questions - https://community.esri.com/t5/arcgis-utility-network/ct-p/arcgis-utility-network

[Tonishatom]

Great question! You’ll likely run into complications if you introduce a single “substation” tier sitting across multiple voltage levels, since the tier hierarchy and rank need to remain consistent for correct tracing and network behavior.

A common approach is to keep the transmission, sub-transmission, and distribution tiers clean, then use containment or connectivity associations to model what’s physically inside substations, instead of a dedicated substation tier. This keeps tracing logic straightforward and avoids cross-tier conflicts.

Also, check out the ESRI Utility Network community — it’s quite active and helpful.

Best of luck modeling your network — shared from texas window!

[RandyVonrueden]

Really insightful discussion here — thank you all for sharing your approaches.

We’ve faced similar challenges when trying to maintain logical tier separation while accounting for physical complexity inside substations. Introducing a dedicated substation tier sounded attractive at first, especially for integration with external systems like ADMS, but ultimately it introduced more tracing issues than it solved.

Like others mentioned, we found that leveraging containment and connectivity associations is a more stable long-term solution. It allows us to keep tier rank logic intact while still querying and managing internal substation assets effectively.

We ran into a similar use case while working on infrastructure mapping tied to delivery zones for Home Direct Blinds, and keeping things modular using associations helped a lot.

Appreciate everyone’s input in this thread!

[JonathanSummit]

Really helpful breakdown on managing substation complexity within the Utility Network! I agree that using containment and connectivity associations keeps things cleaner and avoids rank conflicts.

If anyone’s also looking into detailed infrastructure or utility modeling examples, you can click here to explore some applied design frameworks that align well with tiered network structures.

Appreciate the shared insights from everyone here — these real-world experiences make a huge difference when planning large-scale implementations.

[JonathanSummit]

https://shutterandshades.com/