FAQ - ArcFM - Nominal Versus Operating Voltage

Version 2

    Question

     

    The ArcFM documentation contains a brief description for nominal and operating voltages. Can you provide some additional explanation regarding the difference between these two voltages and how they are often utilized within ArcFM?

     

    Answer

     

    Nominal is outlined in the documentation as the following: “code indicating system voltage; domain values include 7.2 kV Grounded Y, 24.9 kV Grounded Y, 2400 Delta, etc. The ArcFM Inherit Nominal Voltage autoupdater uses the NOMINALVOLTAGE model name on this field.”

     

    The nominal voltage is essentially the level for which a given piece of equipment is designed. A single voltage level is assumed, although this is not always the case. The nominal and operational voltage fields have essentially come to mean the same thing, although there are situations where the distinction between the two is not easily defined.

     

    Operating Voltage is outlined as the following: “code (long integer) indicating standard level at which the system is currently being operated that may vary above or below nominal voltage; domain values include 120 volts, 480 volts, etc."

     

    Operating voltage is the voltage at which the equipment is actually operated. Feeder Manager and Electric Tracing use the OPERATINGVOLTAGE model name on this field. Structural Analysis uses the OPERATINGVOLTAGE model name on this field for overhead conductors.

     

    In practice, and for most utilities, defining the Nominal Voltage for network features is essentially defining a value which is roughly equivalent to the operating voltage. From an applications perspective, OperatingVoltage is used by Feeder Manager to figure out which of the conductors attached to a transformer belong to the primary circuit (which is just passing by) and the secondary circuit (which depends upon the transformer’s windings for its power). The NominalVoltage field is not used at all by Feeder Manager, and is not a required field.