ANSI device numbers
In the design of electrical power systems, the ANSI standard device numbers (ANSI /IEEE Standard C37.2 Standard for Electrical Power System Device Function Numbers, Acronyms, and Contact Designations ) identifies the features of a protective device such as a relay or circuit breaker. These types of devices protect electrical systems and components from damage when an unwanted event occurs, such as an electrical fault. Device numbers are used to identify the functions of devices shown on a schematic diagram. Function descriptions are given in the standard.
One physical device may correspond to one function number, for example "29 Isolating Switch", or a single physical device may have many function numbers associated with it, such as a numerical protective relay. Suffix and prefix letters may be added to further specify the purpose and function of a device.
ANSI/IEEE C37.2-2008 is one of a continuing series of revisions of the standard, which originated in 1928.
List of device numbers and acronyms
- 1 – Master Element
- 2 – Time delay Starting or Closing Relay
- 3 – Checking or Interlocking Relay
- 4 – Master Contactor
- 5 – Stopping
- 6 – Starting Circuit Breaker
- 7 – Rate of Change Relay
- 8 – Control Power Disconnecting Device
- 9 – Reversing Device
- 10 – Unit Sequence Switch
- 11 – Multi-function Device
- 12 – Overspeed Device
- 13 – Synchronous-speed Device
- 14 – Underspeed Device
- 15 – Speed – or Frequency, Matching Device
- 16 – Data Communications Device
- 17 – Shunting or Discharge Switch
- 18 – Accelerating or Decelerating Device
- 19 – Starting to Running Transition Contractor
- 20 – Electrically Operated Valve
- 21 – Distance Relay
- 22 – Equalizer Circuit Breaker
- 23 – Temperature Control Device
- 24 – Volts Per Hertz Relay
- 25 – Synchronizing or Synchronize-Check Device
- 26 – Apparatus Thermal Device
- 27 – Undervoltage Relay
- 27s - DC under voltage Relay
- 28 – Flame detector
- 29 – Isolating Contactor or Switch
- 30 – Annunciator Relay
- 31 – Separate Excitation
- 32 – Directional Power Relay or Reverse Power Relay
- 33 – Position Switch
- 34 – Master Sequence Device
- 35 – Brush-Operating or Slip-Ring Short-Circuiting Device
- 36 – Polarity or Polarizing Voltage Devices
- 37 – Undercurrent or Underpower Relay
- 38 – Bearing Protective Device
- 39 – Mechanical Condition Monitor
- 40 – Field (over/under excitation) Relay
- 41 – Field Circuit Breaker
- 42 – Running Circuit Breaker
- 43 – Manual Transfer or Selector Device
- 44 – Unit Sequence Starting Relay
- 45 – DC over voltage Relay
- 46 – Reverse-phase or Phase-Balance Current Relay
- 47 – Phase-Sequence or Phase-Balance Voltage Relay
- 48 – Incomplete Sequence Relay
- 49 – Machine or Transformer, Thermal Relay-OLR
- 50 – Instantaneous Overcurrent Relay
- 50G - Instantaneous Earth Over Current Relay (Neutral CT Method)
- 50N - Instantaneous Earth Over Current Relay (Residual Method)
- 50BF - Breaker failure
- 51 – AC Inverse Time Overcurrent Relay
- 51G - AC Inverse Time Earth Overcurrent Relay (Neutral CT Method)
- 51N - AC Inverse Time Earth Overcurrent Relay (Residual Method)
- 52 – AC Circuit Breaker
- 52a - AC Circuit Breaker Position (Contact Open when Breaker Open)
- 52b - AC Circuit Breaker Position (Contact Closed when Breaker Open)
- 53 – Exciter or DC Generator Relay
- 54 – Turning Gear Engaging Device
- 55 – Power Factor Relay
- 56 – Field Application Relay
- 57 – Short-Circuiting or Grounding Device
- 58 – Rectification Failure Relay
- 59 – Overvoltage Relay
- 60 – Voltage or Current Balance Relay
- 61 – Density Switch or Sensor
- 62 – Time-Delay Stopping or Opening Relay
- 63 – Pressure Switch
- 64 – Ground Detector Relay
- 64R - Restricted earth fault
- 64S - Stator earth fault
- 65 – Governor
- 66 – Notching or Jogging Device
- 67 – AC Directional Overcurrent Relay
- 68 – Blocking Relay
- 69 – Permissive Control Device
- 70 – Rheostat
- 71 – Liquid Level Switch
- 72 – DC Circuit Breaker
- 73 – Load-Resistor Contactor
- 74 – Alarm Relay
- 75 – Position Changing Mechanism
- 76 – DC Overcurrent Relay
- 77 – Telemetering Device
- 78 – Phase-Angle Measuring Relay or "Out-of-Step" Relay
- 79 – AC Reclosing Relay (Auto Reclosing)
- 80 – Flow Switch
- 81 – Frequency Relay
- 82 – DC Reclosing Relay
- 83 – Automatic Selective Control or Transfer Relay
- 84 – Operating Mechanism
- 85 – Communications,Carrier or Pilot-Wire Relay
- 86 – Lockout Relay/Master Trip
- 87 – Differential Protective Relay
- 88 – Auxiliary Motor or Motor Generator
- 89 – Line Switch
- 90 – Regulating Device
- 91 – Voltage Directional Relay
- 92 – Voltage and Power Directional Relay
- 93 – Field Changing Contactor
- 94 – Tripping or Trip-Free Relay( trip circuit supervision Relay)
- 95 – For specific applications where other numbers are not suitable
- 96 – Busbar Trip Lockout relay
- 97 – For specific applications where other numbers are not suitable
- 98 – For specific applications where other numbers are not suitable
- 99 – For specific applications where other numbers are not suitable
- 150 – Earth Fault Indicator
- AFD – Arc Flash Detector
- CLK – Clock or Timing Source
- DDR – Dynamic Disturbance Recorder
- DFR – Digital Fault Recorder
- DME – Disturbance Monitor Equipment
- ENV – Environmental Data
- HIZ – High Impedance Fault Detector
- HMI – Human Machine Interface
- HST – Historian
- LGC – Scheme Logic
- MET – Substation Metering
- PDC – Phasor Data Concentrator
- PMU – Phasor Measurement Unit
- PQM – Power Quality Monitor
- RIO – Remote Input/Output Device
- RTU – Remote Terminal Unit/Data Concentrator
- SER – Sequence of Events Recorder
- TCM – Trip Circuit Monitor
- LRSS - LOCAL/REMOTE SELECTOR SWITCH
- SOTF - Switch On To Fault
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.[1]
Device numbers may be combined if the device provides multiple functions, such as the instantaneous/time-delay AC over current relay denoted as 50/51.[1]
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.