ANSI Device Numbers

The ANSI standard device numbers ( As per ANSI/IEEE standard C37.2) is used in the design of electrical power system. These devices protects the electrical network in the case of fault in the system. List of ANSI device number with their acronyms are as given below.


List of device numbers and acronyms

  • 1 - Master Element

  • 2 - Time-delay Starting or Closing Relay

  • 3 - Checking or Interlocking Relay, complete Sequence

  • 4 - Master Protective

  • 5 - Stopping Device, Emergency Stop Switch

  • 6 - Starting Circuit Breaker

  • 7 - Rate of Change Relay

  • 8 - Control Power Disconnecting Device

  • 9 - Reversing Device

  • 10 - Unit Sequence Switch

  • 11 - Multifunction 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 Contactor

  • 20 - Electrically-Operated Valve ( Solenoid Valve )

  • 21 - Distance Relay

  • 21G - Ground Distance

  • 21P - Phase Distance

  • 22 – Equalizer circuit breaker

  • 23 – Temperature control device, Heater

  • 24 – Volts per hertz relay

  • 25 – Synchronizing or synchronism-check device

  • 26 – Apparatus thermal device, Temperature Switch

  • 27 – Undervoltage relay

  • 27P - Phase Undervoltage

  • 27S - DC undervoltage relay

  • 27TN - Third Harmonic Neutral Undervoltage

  • 27TN/59N - 100% Stator Earth Fault

  • 27X - Auxiliary Undervoltage

  • 27 AUX - Undervoltage Auxiliary Input

  • 27/27X - Bus/Line Undervoltage

  • 27/50 - Accidental Generator Energization

  • 28 - Flame Detector

  • 29 - Isolating Contactor

  • 30 - Annunciator Relay

  • 31 - Separate Excitation Device

  • 32 - Directional Power Relay

  • 32L - Low Forward Power

  • 32H - High Directional Power

  • 32N - Wattmetric Zero-Sequence Directional

  • 32P - Directional Power

  • 32R - Reverse Power

  • 33 - Position Switch

  • 34 - Master Sequence Device

  • 35 - Brush-Operating or Slip-ring Short Circuiting Device

  • 36 - Polarity or Polarizing Voltage Device

  • 37 - Undercurrent or Underpower Relay

  • 37P - Underpower

  • 38 - Bearing Protective Device / Bearing Rtd

  • 39 - Mechanical Condition Monitor ( Vibration )

  • 40 - Field Relay / Loss of Excitation

  • 41 - Field Circuit Breaker

  • 42 - Running Circuit Breaker

  • 43 - Manual Transfer or Selector Device

  • 44 - Unit Sequence Starting Relay

  • 45 - Fire Detector

  • 46 - Reverse-Phase or Phase Balance Current Relay or Stator Current Unbalance

  • 47 - Phase-Sequence or Phase Balance Voltage Relay

  • 48 - Incomplete Sequence Relay / Blocked Rotor

  • 49 - Machine or Transformer Thermal Relay / Thermal Overload

  • 49RTD - RTD Biased Thermal Overload

  • 50 - Instantaneous Overcurrent Relay

  • 50BF - Breaker Failure

  • 50DD - Current Disturbance Detector

  • 50EF - End Fault Protection

  • 50G - Ground Instantaneous Overcurrent

  • 50IG - Isolated Ground Instantaneous Overcurrent

  • 50LR - Acceleration Time

  • 50N - Neutral Instantaneous Overcurrent

  • 50NBF - Neutral Instantaneous Breaker Failure

  • 50P - Phase Instantaneous Overcurrent

  • 50SG - Sensitive Ground Instantaneous Overcurrent

  • 50SP - Split Phase Instantaneous Current

  • 50Q - Negative Sequence Instantaneous Overcurrent

  • 50/27 - Accidental Energization

  • 50/51 - Instantaneous / Time-delay Overcurrent relay

  • 50/74 - Ct Trouble

  • 50/87 - Instantaneous Differential

  • 51 - AC Time Overcurrent Relay

  • 51G - Ground Time Overcurrent

  • 51LR - AC inverse time overcurrent (locked rotor) protection relay

  • 51N - Neutral Time Overcurrent

  • 51P - Phase Time Overcurrent

  • 51R - Locked / Stalled Rotor

  • 51V - Voltage Restrained Time Overcurrent

  • 51Q - Negative Sequence Time Overcurrent

  • 52 – AC circuit breaker

  • 52a - AC circuit breaker position (contact open when circuit breaker open)

  • 52b - AC circuit breaker position (contact closed when circuit 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

  • 59B - Bank Phase Overvoltage

  • 59P - Phase Overvoltage

  • 59N - Neutral Overvoltage

  • 59NU - Neutral Voltage Unbalance

  • 59P - Phase Overvoltage

  • 59X - Auxiliary Overvoltage

  • 59Q - Negative Sequence Overvoltage

  • 60 - Voltage or Current Balance Relay

  • 60N - Neutral Current Unbalance

  • 60P - Phase Current Unbalance

  • 61 - Density Switch or Sensor

  • 62 - Time-Delay Stopping or Opening Relay

  • 63 - Pressure Switch Detector

  • 64 - Ground Protective Relay

  • 64F - Field Ground Protection

  • 64R – Rotor earth fault

  • 64REF – Restricted earth fault differential

  • 64S – Stator earth fault

  • 64S - Sub-harmonic Stator Ground Protection

  • 64TN - 100% Stator Ground

  • 65 - Governor

  • 66 - Notching or Jogging Device/Maximum Starting Rate/Starts Per Hour/Time Between Starts

  • 67 - AC Directional Overcurrent Relay

  • 67G - Ground Directional Overcurrent

  • 67N - Neutral Directional Overcurrent

  • 67Ns – Earth fault directional

  • 67P - Phase Directional Overcurrent

  • 67SG - Sensitive Ground Directional Overcurrent

  • 67Q - Negative Sequence Directional Overcurrent

  • 68 - Blocking Relay / Power Swing Blocking

  • 69 - Permissive Control Device

  • 70 - Rheostat

  • 71 - Liquid Switch, Level Switch

  • 72 - DC Circuit Breaker

  • 73 - Load-Resistor Contactor

  • 74 - Alarm Relay

  • 75 - Position Changing Mechanism

  • 76 - DC Overcurrent Relay

  • 77 - Telemetering Device, Speed Sensor

  • 78 - Phase Angle Measuring or Out-of-Step Protective Relay

  • 78V - Loss of Mains

  • 79 - AC Reclosing Relay / Auto Reclose

  • 80 - Liquid or Gas Flow Relay

  • 81 - Frequency Relay

  • 81O - Over Frequency

  • 81R - Rate-of-Change Frequency

  • 81U - Under Frequency

  • 82 - DC Reclosing Relay

  • 83 - Automatic Selective Control or Transfer Relay

  • 84 - Operating Mechanism

  • 85 - Pilot Communications, Carrier or Pilot-Wire Relay

  • 86 - Lock-Out Relay, Master Trip Relay

  • 87 - Differential Protective Relay

  • 87B - Bus Differential

  • 87G - Generator Differential

  • 87GT - Generator/Transformer Differential

  • 87L - Segregated Line Current Differential

  • 87LG - Ground Line Current Differential

  • 87M - Motor Differential

  • 87O - Overall Differential

  • 87PC - Phase Comparison

  • 87RGF - Restricted Ground Fault

  • 87S - Stator Differential

  • 87S - Percent Differential

  • 87T - Transformer Differential

  • 87V - Voltage Differential

  • 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

  • 95 – For specific applications where other numbers are not suitable

  • 96 – Transmitter

  • 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


33 views0 comments

Recent Posts

See All

Electrical Ampere is all about articles related to electrical engineering. The site aim to share knowledge about basic electrical, electrical machines, power system, protection system, power quality, DC motor, induction motor, transformer and generator.

  • Facebook
  • Twitter
  • LinkedIn

©2020 by Electrical Ampere.