Transformers

​The ArcFM Utility Network (UN) supports two topology styles for connecting the transformer’s primary terminal to the conductors that supply the transformer with power. We refer to these two styles as the tap and in-line. The style that is used by any given transformer type is indicated by the type’s membership in either the E:Transformer - Tap or the E:Transformer - Inline network category, which are mutually exclusive.

​The UN continues to support the E:Transformer - Tap Category model for connecting distribution transformers freely along the path of an uninterrupted length of primary conductor, but requires a tap junction to sit where power branches from the primary circuit into the transformer.

An electric distribution transformer is a device that lowers high-voltage electricity from the power grid to a safe, usable voltage for homes and businesses. It is essential for delivering electricity efficiently and preventing damage to appliances by stepping down the voltage for end-users. These transformers are commonly seen on utility poles or on pads near buildings

​Transformer devices in general are represented in the ArcFM Utility Network (UN) as features in the devices feature class that have two terminals. One terminal functions as the primary side of the transformer and the other as the secondary side. A three-winding transformer can also be represented in the ArcFM UN as a device that has a third terminal to function as the tertiary side. Each terminal is understood to represent a connection to a circuit with a different VoltageGroup value. 

For example: A Y:Y connected MV/LV transformer will have its primary terminal connected to MV conductors (e.g. VoltageGroup = “12.47kV/7.2kV”) while its secondary terminal will be connected to LV conductors (e.g. VoltageGroup = “120V/240V”).  

​A transformer feature in the device feature class in the electric domain network represents a bank of up to three single-phase transformer units. The ArcFM UN configuration of a transformer bank offers one, two, or three phase-specific paths, with unit objects, between one pair of terminals on the bank, that supports a model of phase propagation through the transformer.

Requirements

• Banks is in the Electric Device Feature Class

• Units are in the Electric Junction Object Table

• Device can be in-line or tapped with an electric junction object

• Must use the E:Transformer network category.

• Device must have two terminals

• Terminal Configuration must be Directional

• Make sure the high side and low side are connected correctly during the data migration.

• Elbow Configuration on a pad mounted transformer must be connected with a connector conductor; do not use electric junction objects.

• Transformer must be either inline or tapped.

Impact on ArcFM

• Has Connected Units - Used if you want Feeder and Phase information propagated to the unit. They are connected and are kept in sync by the UpdateSubnetwork tool. To make this happen, the PhasesNormal attribute is added to the unit. The Terminal Path Configuration Attribute should be set to None.

• Has Disconnected Units – Propagation will impact only the device, and units will not be kept in sync without customizations. Will limit the switchable devices can only be gang operated. Phase Swap does not work with disconnected units. The Terminal Path Configuration Attribute should be set to All.

• No Units – No units are listed for the specified asset group asset type categories. The Terminal Path Configuration Attribute should be set to All.

• Network Category uses in ArcFM Product – See Transformer Network Categories.

• Device must be inline or tapped. The Editor XI Move tool works with inline and tapped transformers. The Editor XI Split tool only works on inline transformers.

• In Designer XI, the deletion of a transformer triggers the automatic removal of the associated tap junction feature and its connectivity associations. Line split prevents the transformer from being treated as a conductor split point during design push.