Electrical Networks - Advanced Configuration
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The Electric Networks - Basic Configuration article focused on some of the standard configuration tasks that an electrical customer might perform on their network. In this article, we will be taking a deeper dive to look at some of the more advanced configurations that a customer may choose to implement on their electric utility network.
These are configurations needed to address the business requirements for some customers which require a bit more work to configure or impose new data quality constraints. Smaller customers may find they can adequately meet their requirements without applying some or all these configurations, but many larger customers may rely on these configurations to support key asset management or analysis workflows.
Attaching Equipment
Many customers manage a relationship between equipment and structures in their GIS. This is used to support joint use, structural analysis, and a wide range workflows associated with asset management. While these relationships can continue to be maintained as relationship classes in the utility network, some customers choose to represent them as attachment associations.
Using associations to model the relationships between equipment and structures has the benefit of making it easier to track and analyze the relationships between the electrical and structural networks because it allows traces to return structures in their analysis or even include them in extracts to other systems. Let’s look at how to add a structural attachment association between poles and transformers.
To add an association between two features there must be a rule that allows them to be associated, but before a rule can be added, you must identify what type of associations you want to be allowed for use with each structure. There are two association roles that can be assigned to a structure:
- Structure – A structure is a feature like a pole that has equipment attached to it.
- Container – A container is a feature like a cabinet or vault that contains equipment.
The first step is to set the association role for poles to allow features to attach to them. This is done by using the Set Association Role tool to assign the structure role.
Once the different asset types for poles have been configured as structures, you can then add rules allowing different types of equipment to attach to them.
Once you’ve added this rule, you can then use the Modify Associations pane to add a structural attachment between a pole and a transformer.
Once this attachment has been created, the pole can then be included in any trace results that also include the transformer when the trace is configured to “Include Structures”.
If you have existing relationships between poles/equipment that you want to migrate, you can use the Import Associations tool to import a CSV file containing the identifying information for all of your attachment associations.
Attaching Conductors
Another relationship managed by some utilities is the relationship between conductors and the structures that support them. While this relationship can be modeled using relationship classes or associations, it does require a few additional steps. This is due to the feature restrictions of the utility network which do not allow for a line to be directly attached to a structure.
Conductors are only allowed to attach to structures through the devices and junctions they are connected to. This means you don’t have to worry about maintaining associations between conductors and structures when a piece of equipment is already attached to the structure. For the remaining structures that have conductors attached without any equipment we need to create a junction feature, typically called an attachment, followed by a rule that allows that attachment junction to be attached to the structure.
Containment
The process for creating containment associations is almost identical to that of attachment associations. First, set the association role of the structure to be a container. You can optionally set a view scale, so when you view the contents of a container the map will zoom to the feature’s extent or a particular scale.
Then, instead of adding an attachment rule you would add a containment rule.
Once the rule is added, you can then add features as content to the containers structure features.
Propagating Phase
Customers who use their electrical data for engineering analysis or outage management know the importance of maintaining accurate phasing data in their GIS. It’s important that the GIS be able to use phasing to determine which features are energized so when phase information is improperly captured by office or field staff it can be immediately validated and corrected. If bad phasing information is allowed to exist in the GIS, it will prevent engineers and operators from being able to perform the work necessary to ensure that the utility can provide service to customers safely and reliably. The topic of phase propagation, along with instructions on how to configure it, is described in this article: Exploring Propagation and Attribute Substitution in Subnetwork Management
You can configure your utility network to use phasing to energize features by configuring your electrical phasing network attribute as a field that is propagated in your network. Before configuring phase propagation, you should ensure that your data has no topology errors and that you are confident that all the features in your network are properly energized.
Why? Because enabling phase propagation will cause features to be de-energized if the phasing information is incorrect, and it's easier to resolve these energization issues if you aren’t also concerned about phasing. You’ll also see that by having the original subnetworks calculated without phasing it makes it easier to identify de-energized features caused by phasing.
If you read the article discussing phase propagation, you’ll realize that the first thing we’ll need to do is add a field to your devices, junctions, and lines to store the propagated phasing value. This field should have the same domain and data type as your normal phasing attribute.
Because your feature classes have subtypes you should also assign that domain to each subtype in those tables, this will ensure that each subtype can properly display the coded value for the energized phases.
Once you’ve added the field with the correct domain, you then need to update the subnetwork definition to propagate the phasing value to the newly added field. First you will need to disable your network topology to make an administrative change to your utility network. This parameter is not visible on the Set Subnetwork Definition tool, so you will either need to use Python or Model Builder to populate the parameter with the appropriate value.
Once you’ve updated the subnetwork definition you then enable your network topology and repeat the process for updating all your subnetworks and performing quality assurance.
If all your features were energized before you configured propagation, you can be certain that any features that are now de-energized are due to a problem with your phasing data. In fact, when you first update your subnetworks, you will likely find that most of your features are de-energized! Why is this?
In the phasing and propagation article mentioned referenced at the beginning of the section, you saw how placing a single-phase device on a three-phase line would restrict the phasing of the three-phase line to be single-phase. While this makes sense for devices like switches and fuses, which are installed in-line with the conductor, there are other devices such as transformers where this doesn’t make sense. If you draw your single-phase transformers in-line with two-phase or three-phase conductors, as many electric customers do, this will result in many of your features becoming de-energized. We’ll show you how to configure transformers to behave properly in the utility network in the next section.
You can also find tips on how to troubleshoot other tracing and phasing issues in the Electric Quality Assurance article.
Terminals
As we discussed above, when the utility network is propagating phase, transformers are restricting the phases as if the connectivity is passing through the transformer. This is because the transformer is drawn in-line with the medium voltage conductor it is attached to. While you could choose to redraw all your transformers to be offset from the line, a simpler approach is to configure the transformers with terminals on their high-side and low-side to allow the transformers to tap into the medium-voltage conductor without restricting the phasing on the high-side. The only downside to this approach is that you will need to split any conductors that have a transformer drawn midspan.
To begin configuring the new terminals we must first disable the network topology to make an administrative change.
Next, we create a new terminal configuration to the utility network using the Add Terminal Configuration tool.
Once we’ve created this terminal configuration, the next step is to assign it to all the different transformer asset types that we want to not restrict phasing using the Set Terminal Configuration tool. Distribution transformers will benefit from this terminal configuration, but assigning this terminal configuration to step or power transformers is something you will want to consider more deeply.
The good news is that now each of these asset types has a high-side and low-side terminal that can be connected to. The next step is to configure connectivity rules that determine which types of lines are connected to each terminal. We will discuss this in the next section.
Junction-Edge Rules
Rules in the utility network determine what kinds of features are allowed to connect to other kinds of features. Junction-edge rules are the rules that determine which types of point features are allowed to connect to which types of lines. When a point feature has terminals, the rule must specify which terminals on that feature are allowed to connect to each type of line. This is important in the case of features like transformers because only certain types of lines are allowed to connect to each terminal. A walkthrough example demonstrating how to configure connectivity rules for transformers with terminals below.
First, before making administrative changes to the utility network you need to make sure the network topology is disabled. You can do this by either checking the network properties for your network, or by running the Disable Network Topology tool.
Once the network topology is disabled, open the Add Rule geoprocessing tool. In the previous section you added high-side and low-side terminals to the transformers. In this section you must define what types of lines they are allowed to connect to. If no rules are configured for these terminals, you will get connectivity errors for all your transformers. Fortunately, the require rules are straightforward.
First, you configure rules that allow the high-side terminal of a distribution transformer to connect to any medium voltage line.
Then, add rules to allow the low-side terminal of each distribution transformer to connect to low-voltage lines.
In the case of step or power transformers that can have medium-voltage lines on either side, you have several choices. If you add rules that allow the same type of line to connect to different terminals on the device, then we will need to use the Modify Terminal Connections pane to manually assign the terminal connections for each line connected to a step or power transformer. Your other option would be to not assign the transformer terminal configuration to those asset types and accept that they will restrict phasing and allow power to flow bi-directionally.
Either way, once you’ve finished adding rules for all your different asset types, you’re ready to re-enable the network topology. You should consider using the Delete Rules tool to remove the original Junction-Edge rules for any transformers you added a terminal configuration to, since these rules are no longer applicable. If you’ve configured everything correctly you shouldn’t have any invalid connectivity errors on your distribution transformers. However, if you had any transformers that were drawn midspan on electric lines, you will receive topology errors for those lines/devices.
Fixing these errors is as simple as using the Select By Location and Splits tool to select then split the electric lines that have midspan transformers.
First, open the Split tool and set it to split By Feature and make sure you’re on the Input Features tab.
Use the Select By Location tool to select all the transformers that are midspan to electric lines by using the Within Clementini operator. This selects all the transformers that intersect with the inside of an electric line, but not its endpoints.
This will populate the input features on the Split Tool. Next switch to the Target Features tab on the Split tool.
Next, you’ll select all the electric lines that Contain Clementini a transformer.
With the Input Features and Selecting Features parameters populated click Split. Once you enable your network topology most, if not all the Midspan Connectivity errors should be resolved. If you have any remaining topology errors, refer to the Electric topology errors article for tips on how to resolve them.
You may notice that every time you disable and enable your network topology that all your subnetworks become dirty. This is the expected behavior. Every time you modify the schema of your utility network all your subnetworks need to be updated to make sure they are still valid and to evaluate the network using the newest configuration.
Conclusion
Now that you’ve finished this article you know how to configure associations to manage containers and content in your utility network. You should also be familiar with how to configure phase propagation, so your electrical phasing is validated each time you run update subnetwork. Read the explore propagation and attribute substitution in subnetwork management article if you want to learn even more about this topic. Finally, you learned about the benefits of terminals and the steps required to configure terminals and adjust your connectivity rules to account for these more granular connections.
If you want to know more about using the utility network to manage electrical networks, please explore the Learn ArcGIS Utility Network for Electric Utilities series. This learning series includes tutorials and articles that demonstrate how to address the needs of the electric industry using the utility network.
As always, if you have any questions or comments be sure to ask them in the Esri Community site!
