Subnetwork Modelling in Esri UN

[KokilaM]

Hi community,

We are currently working through subnetwork modeling decisions that span across Distribution, Transmission and Substation tiers in a Utility Network implementation. We wanted to reach out to the community to understand how others have handled this — particularly around substation subnetwork configuration.

Our core questions:

• Is anyone modeling multiple subnetworks within a single substation?
• Is anyone modeling substation subnetworks in a way that supports true end-to-end tracing — from a transmission circuit, through the substation, all the way down to impacted customers?

  To provide context, the Transmission Terminal serves as the connection point where a transmission circuit terminates at a substation, acting as the start and end point of a transmission line. However, in some substations the connectivity extends beyond the terminal, travelling through to the substation transformer via the primary bus. Since the subnetwork controller for transmission encompasses all terminals within the circuit, fixed start and end point designations are not considered functionally significant.

  In a substation, multiple devices are connected to the primary bus of a Transmission Terminal, and determining which device acts as the subnetwork controller is critical for accurate network tracing and isolation.

  Additionally by end-to-end tracing we mean that if a transmission circuit upstream of a substation needs to be traced, can an analyst trace through the substation subnetwork and identify downstream customers? This level of granularity is what we are working towards, and getting the subnetwork controller configuration right — for Distribution, Transmission and Substation tiers — is critical to making it work.

  If you have implemented something like this, we'd love to understand:

  1. What Features, Asset Groups (AG), and Asset Types (AT) are you using as Transmission tier subnetwork controllers?
  2. What Features, Asset Groups (AG), and Asset Types (AT) are you using as Substation tier subnetwork controllers?
  3. Are there any modeling pitfalls or lessons learned you'd flag for someone setting this up?

     We want to make sure our approach aligns with community best practices.

      would also appreciate any guidance from the Esri side on how this is typically approached.Thanks in advance!

     •  

     @RobertKrisher @MikeMillerGIS 

[RobertKrisher]

If you download the Electric Utility Network Foundation you can see examples for everything you've asked about above. Are you focused more on an American style unbalanced network? or a European style balanced network?

In an American style network you will have a power transformer that models the stepping down of voltage from transmission levels to distribution levels, this can be configured as a subnetwork controller for a distribution circuit within the substation. Each distribution circuit/feeder is controlled by a circuit breaker, and this is almost always set to be a subnetwork controller.

Things are a little different for the European model, but before I dig into the details there (and point you to some other resources) I want to confirm which approach you're looking for.

[gis_KIWI4]

Hi @KokilaM - This is how we do it.
We don't have a dedicated substation subneworks.
This is a distribution substation where the sub-transmission network (33kV - blue lines) connects to the power transformers and Distribution network (11kV - red lines) 

In the substation we have 2 Tiers - Subtransmission and Distribution. 
The Subtransmission Tier goes all the way to the circuit breakers (highlighted yellow) 
The Distribution Tiers (pink and purple) are essentially feeders/ The CBs are subnetwork controllers. 

We have end to end tracing via just 3 tiers Subtransmission Tier -> Distribution Tier -> Low Voltage Tier 

A key takeaway here is not naming you Tiers based on Voltage but rather function.
See above have the Subtransmission Tier has both (33kV and 11kV) bits in it.

Also note we have 2 distinct asset groups - Circuit Breaker and Circuit Breaker (non-subnetwork controller) 
only the feeder CB are subnetwork controller type and the rest of the CBs in the substation are non-subnetwork controller type. This is because the directional terminal requirement of the subnetwork controllers. 

Subtransmission Tier Subnetwork Controller = 33kV CB at the Grid Exit Point
Distribution Tier Subnetwork Controller = 11kV CB at the distribution substations
Low Voltage Tier Subnetwork Controller = local Distribution Transformers

[RobertKrisher]

@gis_KIWI4 that's a pretty typical approach. The place where I've seen customers (mostly North American) model their substation (Transformer to Distribution Feeder) as a subnetwork is when they want to use the GIS to feed the substation internals in their OMS/ADMS.

[Jens_Dalsgaard]

If you're looking at setting subnetwork controllers in a balanced three phase grid as operated in large shares of the world outside USA, you may download the Volue UN Implementation Guide for Balanced Three Phase Distribution Grids that come with quite an extensive sample dataset. In this sample dataset, you may trace across tiers (though the dataset does hold subnetwork controllers feeding the high voltage tier - but you could easily set that up and test)

https://www.linkedin.com/posts/danielahaldy-sellmann_distribution-arcgis-utilitynetwork-activity-746...

What this implementation guide promotes is setting up subnetwork controllers on the secondary (and tertiary) windings of the transformers. 

For substations with multiple parallel transformers you will then have two or three subnetwork controllers. 

Subnetwork controller name would then typically be:

1. Substation 100 - T1 Sec
2. Substation 100 - T2 Sec

That is, unique naming.

But as such transformers will often be operated in parallel and hence feed the same subnetwork, for both subnetwork controllers the Subnetwork name would typically be:

• Substation 100

for both subnetwork controllers