Relay Codes for all Relay From 1 to 150 Numbers

ANSI Codes for Relay Units

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 supervisen 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

Relay Codes
Relay Codes

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