Introduction
Does the following dilemma sound familiar to you?
“I have been using ArcMap for years. And now I want to adopt the Utility Network because of its Out-Of-The-Box (OOTB) subnetwork management capabilities. Yet, I hear about its complexity and feel apprehensive about the transition.”
This apprehension is justified if what you hear is that, for example, to place a three-phase in-line switch somewhere along the circuit’s backbone you had to:
Figure 1 – Associative UN implementation.
- Split the line and open a gap, say of 10 feet.
- Place one junction at each new end vertices of the receded lines.
- Place three switch devices somewhere in between (kind of floating in the air).
- Establish connectivity associations between the fuses and the junctions. And, if using terminals, be extra careful.
- Not to mention containing these elements in an assembly to declutter the map.
You, as an editor, are left wondering “what happened to my trusty workflow?”: selecting a feature and dragging it over the map until it snaps to the line. You, as a manager, are left wondering “how many hours are my editors going to need to finish their jobs? How many workflows, reporting capabilities, and integrations will be affected by this transition? How much time will the team take to learn the new ways?”
Figure 1 – Geo-Coincident UN implementation.
The extra complexity is understandable and fully justified if your goal is to create a digital twin in which the commodity, in this case electric power, flows through your assets: your actual wires, fuses, switches, transformer cans, etc. But what if a digital twin is not your goal? Is there an alternative implementation of the UN that, without losing any of the OOTB subnetwork management functionality, allows you to continue using your familiar editing workflows? Furthermore, could this implementation also bring along all the fields and domains on which so many of your applications already depend? In essence, could the impact on the organization be minimized while transitioning into, and obtaining the maximum benefit from the UN?
Yes. SSP EDM is a UN implementation that maximizes OOTB functionality and minimizes Organization Change Management (OCM) impact.
What is SSP EDM?
SSP Electric Data Model, SSP EDM for short, is a Utility Network schema with association rules that implements a geo-coincident (snap-based) network while supporting OOTB:
- Phase Propagation.
- Per-Phase Operability.
The model uses the well-known Banks/Units representation, where:
- Banks are ElectricDevice features implementing the behavior of the equipment.
- Units are ElectricJunctionObject objects contained in the Banks and represent the actual assets.
- Banks snap to lines, based on selected Connectivity Rules.
Furthermore, SSP EDM is simply extended with the fields and coded-value domains that are meaningful to each organization.
The result? A UN that, to editors, looks and feels like the familiar GN. And, to managers, it maintains the interoperability of the GIS with minimal changes to existing workflows.
Let us be clear, though. Our goal is not to provide a like-for-like, but to offer the opportunity to reassess the value of your GIS within the enterprise with minimal disruption to your GIS team and the other business units. Let’s dive deeper into the details and discover for yourself.
The Secret Sauce
The geo-coincident Banks/Units model became possible a couple of years ago when Esri released Non-Spatial Objects (NSO’s) as part of the core schema of the UN. Resembling the familiar Object related to Feature model in ArcMap, SSP EDM uses Containment Association to include Units in their Banks, and Connectivity Rules to support snapping of equipment to lines.
To exploit OOTB Phase Propagation to its maximum capabilities, editors only need to set phases in Units and Taps. No more setting phases in lines and Banks, as these are updated directly from propagation. For example, Transformer Banks draw power from primary lines according to the phases of their Units (see diagram below). SSP EDM also implements operability-by-phase by simply toggling the status of operable Units (Open/Closed). For example, a three-phase Switch Bank that is open on B, and closed on A and C, as shown in diagram below.
Figure 2 – SSP EDM supports Phase Propagation and Per-Phase Operability via its Units.
Behind the scenes, a couple of Immediate Calculation Attribute Rules adjust the behavior of the Banks based on the values of its Units. This automation allows editors to focus on their main tasks: placement of equipment, lines, and structures. The management of the subnetworks is left to the UN.
A Minimalistic Model
During this development, SSP also decided to build a model in which every new element is recognized as necessary for successful UN implementation. The model is justified based on the following criteria:
- Asset Group – Only if a business case requires layer property differentiation. For example, if SSP EDM offers Fuse Bank and Transformer Bank asset groups it is not because those are different kinds of equipment, which they are, but rather because the former layer should display Positions A, B, and C, while the latter must show Total kVA instead.
- Asset Types – Only the minimal set to support Association Rules. For example, equipment asset types are mainly Overhead and Underground, so that each type snaps to the corresponding lines. As another example, if SSP EDM differentiates between Manholes and Vaults, it is not because they are different structures, which they are, but because the former is configured to support Attachment Association and the latter Containment Association.
- Fields and Domains – Only those needed by application-specific use. By design, SSP EDM does not have any business-like attributes. Instead, the model is extended with the fields and domains dictated by justified use cases. For example, an organization has built reports on Manufacturer as a Text(5) field whose values are defined by business-driven domain. The same Manufacturer field is brought to SSP EDM as is, minimally affecting the reporting workflows.
- Terminals – Only when absolutely necessary. SSP EDM configures terminals on Subnetwork Controllers (mandated by UN), Transformers (to tap individual phases from the Primary line), and a couple of asset types to support phase splitting. For example, two single-phase laterals of different phases, say B and C, tap off a segment of the three-phase backbone.
In Closing…
SSP EDM is a UN schema with a restricted set of rules that implements a geo-coincident network that, automatically, supports Esri’s OOTB Subnetwork and Phase Management capabilities. The model is fully extensible with the fields and domains needed by your organization.
What do you think?