Units in the Balanced and Unbalanced Model

The ArcFM Utility Network (UN) defines the E:Has Connected Units and E:Has Disconnected Units network categories as a way to distinguish types of devices that are intended to have units and those that are not. Units are categorized as non-spatial objects that belong to the E:Unit network category. Any feature type that belongs to the E:Has Connected Units or E:Has Disconnected Units category must contain units.

A balanced model implementation of ArcFM UN is unlikely to have devices that belong to the E:Has Connected Units category. Balanced models that require unit data to support asset management use the E:Has Disconnected Units network category.

The unbalanced model implementation is likely to have only devices that belong to the E:Has Connected Units category.

A given ArcFM UN can mix and match types from the balanced and unbalanced model that define some devices that have units and other device or conductor types that do not have units. It is generally preferred to commit to one or the other arrangement; either all devices have units, or none do. Other considerations, such as data needs of integrated systems, or the existence of small pockets of unbalanced equipment in a mostly balanced system, can lead to an ArcFM UN that includes some equipment types that have units and others that do not. If the E:Has Connected or E:Has Disconnected Units network categories have been assigned to an asset type, all features associated with that asset type must have unit records.

Connected Units

If a customer wants energized units in a downstream system, such as ADMS, use connected units. This configuration is most likely a concern only in an unbalanced network. The unit records stored in the non-spatial object tables participate in connectivity. Phase and the device status (open/close) are tracked by the unit records. When unit records are edited, an attribute rule is required to keep the device(bank) and the unit’s phase and device status in sync. Unit records need to be contained by the device(bank) and connected. The TerminalConfiguration field value on the device(bank) record is set to None.

Disconnected Units

If a customer wants to track units for a specific purpose, such as asset management, but do not want energized units in a downstream system, such as ADMS, they should use disconnected units. This is most likely used in a balanced network. The unit records are stored in the non-spatial object tables, but do not participate in connectivity. The unit records help with asset management to help track maintenance and replacement records of an individual piece of equipment within a bank. The TerminalConfiguration field value on the device(bank) record is set to All. The unit records do not have information about the phase or device status. No attribute rule is needed. Unit records need to be contained by the device(bank).

Conductor Units

Conductors use only the E:Has Conductor Info network category to differentiate when units are present for both balanced and unbalanced models. Because edge objects in the UN do not have terminals when a conductor line feature has units, or contains objects in the non-spatial electric edge objects table, the units have a phase attribute, but does not participate in electrical connectivity.

Using Passthrough Units

Passthrough units are used in the unbalanced model when single-phase or two-phase units are placed on a three-phase conductor. When a single-phase in-line device is installed on a three-phase conductor, passthrough units must be placed in the device(bank) as non-spatial unit records. When using Passthrough units, these units must be modeled in a different AssetGroup AssetType pair with the E:PassThrough category assigned. Passthrough units are noted with the E:Pass Through network category. Without passthrough units, the flow on the remaining phases stops at the device. Single-phase tapped devices do not require passthrough units but do require the connection tap feature to have its PhasesNormal to be set to all phases of the line it is tapping from.

Required Configuration

• If using the E:Has Connected Units category, set the TerminalConfiguration field default value to none.

• If using the E:Has Disconnected Units category, set the TerminalConfiguration field default value to all, or no network category.

• If combining balanced and unbalanced features within the electric device feature asset group, set the value for the TerminalConfiguration field according to the recommendation of the predominance of balanced or unbalanced features.

• For E:Has Connected Units, devices should have an autoupdater that sets the PhasesNormal field and the DeviceStatus on the ElectricDevice feature class. A mismatch between PhasesNormal on the device and units can cause tracing issues.

• Only a device in the E:Has Connected Units or E:Has Disconnected Units network category can be named a container by at least one UN containment rule.

• Passthrough units must be used in the unbalanced model when single-phase or two-phase units are placed on a three-phase conductor. Passthrough units are noted with the E:Pass Through network category.

• Conductors must use the E:Has Conductor Info network category.