Equipment Model Topology — Unbalanced Equipment

Bank/Unit Model for Unbalanced Equipment

In the unbalanced model, each device feature can represent up to three different phase-specific components of similar function. We refer to the feature as a bank, and to its phase-dedicated components as units. For example, a three-phase transformer bank may have an unbalanced transformer bank with a 25kVA transformer unit on phase A, a 15kVA transformer unit on phase B, and a 25kVA transformer unit on phase C.

Recommended Configuration

• Represent the bank in the ElectricDevice feature.

• Represent the rows of a bank in the JunctionObject table of the electric domain network.

• Set each row with a PhasesNormal attribute to indicate the unit’s phase affiliation, and any other attributes needed to make the unit unique within the bank.

  For example, the units that belong to a switch bank, or an electric domain network feature device class, each have a DeviceStatus attribute value to indicate that each phase has an independent open and closed state.

• The bank feature is related to its unit rows with a UN containment association. The bank is the container in this asymmetrical association, and the unit is the content.

• When a device has units, both the device and the units participate in UN connectivity.

• The units are connected to the device internally only. Each unit is connected directly between the two terminals of the device and is not connected to any other features.

• When units are present, the network category E:Has Connected Units should be applied to the device. Set the TerminalConfiguration field value on the device(bank) record to None.

• When units are present, the pathway for electric current through the device must enter one of its terminals, proceed from there to each of the units and then to the other terminal, where it exits the device to flow into the neighboring network features. This connectivity description applies to all bank-type devices in the electric domain network that have two terminals, except devices that serve as subnetwork controllers.

Product Limitation

• ArcFM Designer XI currently supports only Symmetric Units. In the pull from the UN to ArcFM Designer XI and Feeder Services, all units will match.

​Bank/Unit Model for Unbalanced Equipment

The example switch bank with units shows the internal junction-to-junction connectivity details. The switch bank (blue box), which is stored in the device feature class in the electric domain network, has terminals T1 and T2, and it contains three units A, B, and C that are each connected using the junction to junction associations across the terminals. Each unit is stored in the non-spatial JunctionObject table in the electric domain network. The DeviceStatus attribute of the phase A unit (open or closed) determines whether phase-A electrical current can travel through the device, and similarly for the phase B and phase C units.