Balanced and Unbalanced Electrical Phase Models

Electric distribution systems conform to design and construction practices that have evolved differently in different parts of the world. Some properties of distribution systems are the same everywhere. Almost all of them are alternating current three-phase, but may differ in frequency and in end-user voltage levels. The important characteristics that divide power distribution networks into two classes is how many phases of power the network carries and the equipment can have different properties for different phases. This difference is so pronounced, and the corresponding differences in engineers’ conceptual and numerical models of equipment are so great, that the networks are described by two distinct data models, balanced and unbalanced, to represent electric distribution network facilities using Esri’s Utility Network (UN).

Here is an example of a balanced network.

Here is an example of an unbalanced network.

Recommended Configuration

• The balanced ArcFM UN is best suited to distribution systems whose users never have a need of accounting for phase-specific differences in any length of conductor or in any transformers, switches, fuses, meters, or other electric equipment.

• The unbalanced ArcFM UN is the best choice for a system that must faithfully model different properties per phase for any length of conductor or any piece of equipment.

• The balanced and the unbalanced models are not mutually exclusive. An ArcFM UN implementation can choose one or the other model as the guiding pattern for the feature types defined by the implementation, and still include some feature types from the other model. This configuration may be needed to fulfill specific needs for function and integration, for example, or to accommodate cases of unusual design or equipment that may be present in a small fraction of the electrical system.