Tiers

The ArcFM Utility Network (UN) is focused on the representation of electric distribution facilities.

Subdividing a network into tiers allows data to be organized into discrete sections to improve the performance of analysis tools such as Update Subnetwork Geoprocessing. Further, subdividing provides boundaries to make sure that data exported with the Export Subnetwork feature service is understood by integrated systems to handle a specific network segment of the distribution circuit.

Requirements

• Configure transmission lines in their own tier.

• Tiers in Balanced Networks - define the Transmission, Distribution, and Secondary Mesh lines into separate tiers

• Tiers in Unbalanced networks - Distribution and Low Voltage Radial networks should be in the same tier, while Secondary Mesh networks should be in its own tier.

• Configure the tier definition in the electric domain network as partitioned.

  For more information about tiers, see the Esri topic Utility Network Tiers.

When you subdivide a network into tiers:

• The data is organized into independent sections and improves the performance of network analysis tools, such as Update Subnetwork. Subdividing the GIS data into tiers allows an organization to keep both types of data in a single geodatabase.

• The boundary of the defined network segment keeps exported data in an accepted format for integrated systems, such as an Outage Management System (OMS). Tier boundaries fall near, but not at, transformers that change nominal voltages. These requirements apply to all equipment at the substation, not just the portions on the low side of the substation transformers. The demarcation points between the substation and the distribution are the last device in the substation as opposed to the transformer where the voltage is reduced.

• The tier is based on the nominal voltage expected to be carried by the equipment in that segment. This is because different skills, business processes, and equipment (and integrated software) are required to build and maintain electric distribution systems at different voltage levels.

• A subnetwork controller is a device that delimits one tier to another at the boundary point. These boundaries are mainly at substations where the nominal voltage is changed. A distinctive feature designated to be a subnetwork controller must be present at the boundary points which join one tier to the next. The subnetwork controllers are usually the last device in the substation (switches or fuses), not the transformers where the nominal voltage is changed.

Impact on ArcFM

• ArcFM requires the definition of the distribution tier. You can still trace Transmission, Mesh, and Low Voltage tiers.

• Designer XI works best with a distribution tier and has limited capabilities in Transmission

• Feeder Services requires Secondary assets to be in its own tier for the Balanced Model because of performance issues. Tier setup should be carefully reviewed and understood as it relates to updatesubnetwork and exportsubnetwork performance.

  You may need to use the Export Subnetwork files created by Feeder Services to create a custom interface with ADMS.