ANSI device numbers explained

In electric power systems and industrial automation, ANSI Device Numbers can be used to identify equipment and devices in a system such as relays, circuit breakers, or instruments. The device numbers are enumerated in ANSI/IEEE Standard C37.2 Standard for Electrical Power System Device Function Numbers, Acronyms, and Contact Designations.

Many of these devices protect electrical systems and individual system components from damage when an unwanted event occurs such as an electrical fault. Historically, a single protective function was performed by one or more distinct electromechanical devices, so each device would receive its own number. Today, microprocessor-based relays can perform many protective functions in one device.[1] When one device performs several protective functions, it is typically denoted "11" by the standard as a "Multifunction Device", but ANSI Device Numbers are still used in documentation like single-line diagrams or schematics to indicate which specific functions are performed by that device.

ANSI/IEEE C37.2-2008 is one of a continuing series of revisions of the standard, which originated in 1928 as American Institute of Electrical Engineers Standard No. 26.[2]

List of device numbers and acronyms

Acronyms Description

Suffixes Description

Suffixes and prefixes

A suffix letter or number may be used with the device number; for example, suffix N is used if the device is connected to a Neutral wire (example: 59N in a relay is used for protection against Neutral Displacement); and suffixes X, Y, Z are used for auxiliary devices. Similarly, the "G" suffix can denote a "ground", hence a "51G" is a time overcurrent ground relay. The "G" suffix can also mean "generator", hence an "87G" is a Generator Differential Protective Relay while an "87T" is a Transformer Differential Protective Relay. "F" can denote "field" on a generator or "fuse", as in the protective fuse for a pickup transformer. Suffix numbers are used to distinguish multiple "same" devices in the same equipment such as 51–1, 51–2.[3]

Device numbers may be combined if the device provides multiple functions, such as the Instantaneous / Time-delay Overcurrent relay denoted as 50/51.

For device 16, the suffix letters further define the device: the first suffix letter is 'S' for serial or 'E' for Ethernet. The subsequent letters are: 'C' security processing function (e.g. VPN, encryption), 'F' firewall or message filter, 'M' network managed function, 'R' rotor, 'S' switch and 'T' telephone component. Thus a managed Ethernet switch would be 16ESM.

References

Notes and References

  1. Web site: Kunsman . Steven . December 1, 2011 . The Protective Relay Evolves . Power Grid International.
  2. Web site: Tengdin. John. Knowing the Language: The History and Practice of IEEE C37.2. Electric Light & Power. PennWell Corporation. 18 October 2017. 1 February 2009. It may surprise some to learn that this standard—or more accurately its AIEE predecessor—is one of the oldest IEEE standards in use. It was first published as AIEE No. 26 in 1928 and was used to document the control systems in the then popular automatic railway substations..
  3. Applied Protective Relaying 1979 by Westinghouse Electric Corporation, 2nd Printing, "Appendix II, Electrical Power System Device Numbers and Functions" as adopted by IEEE standard and incorporated in American Standard C37.2-1970.

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