23598960 relay symbols and device number ieec 37 (1)

8/2/2019 23598960 Relay Symbols and Device Number IEEC 37 (1)

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Relay symbols and device numbers;selection from IEC 617-and ANSI/IEEE C37.2-1991


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2. time-delay starting or closing relay is adevice that functions to give a desired amount -of time delay before or after any point ofoperation in a switching sequence or protectiverelay system, except as specifically provided bydevice functions 48, 62, and 79.

3. checking or interlocking relay is a relaythat operates in response to the position of anumber of other devices (or to a number ofpredetermined conditions) in an equipment, toallow an operating sequence to proceed, or tostop, or to provide a check of the position ofthese devices or of these conditions for anypurpose.

12. overspeed device is usually a direct-connected speed switch which functions onmachine overspeed.

14. underspeed device is a device thatfunctions when the speed of a machine fallsbelow a predetermined value.

21. distance relay is a relay that functionswhen the circuit admittance, impedance, orreactance increases or decrease beyond apredetermined value.

25. synchronizing or synchronism-checkdevice is a device that operates when two accircuits are within the desired limits offrequency, phase angle, and voltage, to permit

or to cause the paralleling of these two circuits.

26. apparatus thermal device is a device thatfunctions when the temperature of the shuntfield or the amortisseur winding of a machine, orthat of a load limiting or load shifting resistor, orof a liquid or other medium exceeds apredetermined value; or if the temperature ofthe protected apparatus, such as a powerrectifier, or of any medium decreases below apredetermined value.

27. undervoltage relay is a relay which

operates when its input voltage is less than apredetermined value.

30. annunciator relay is a nonautomaticallyreset device that gives a number of separatevisual indications upon the functioning ofprotective devices, and which may also bearranged to perform a lockout function.

32. directional power relay is a relay whichoperates on a predetermined value of powerflow in a given direction, or upon reverse powersuch as that resulting from the motoring of a

generator upon loss of its prime mover.

2.

14. , ()

21.

27. -

30.

32.


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836. polarity or polarizing voltage device is adevice that operates, or permits the operationof, another device on a predetermined polarityonly, or verifies the presence of a polarizingvoltage in an equipment.

37. undercurrent or underpower relay is arelay that functions when the current or power

flow decreases below a predetermined value.

38. bearing protective device is a device thatfunctions on excessive bearing temperature, oron other abnormal mechanical conditionsassociated with the bearing, such as unduewear, which may eventually result in excessivebearing temperature or failure.

37. --

39. mechanical condition monitor is a devicethat functions upon the occurrence of anabnormal mechanical condition (except thatassociated with bearings as covered under

device function 38), such as excessivevibration, eccentricity, expansion, shock, tilting,or seal failure.

40. field relay is a relay that functions on agiven or abnormally low value or failure ofmachine field current, or on an excessive valueof the reactive component of armature current inan ac machine indicating abnormally low fieldexcitation.

46. reverse-phase or phase-balance currentrelay is a relay that functions when the

polyphase currents are of reverse-phasesequence, or when the polyphase currents areunbalanced or contain negative phase-sequence components above a given amount.

47. phase-sequence voltage relay is a relaythat functions upon a predetermined value ofpolyphase voltage in the desired phasesequence.

48. incomplete sequence relay is a relay thatgenerally returns the equipment to the normal,or off, position and locks it out if the normal

starting, operating, or stopping sequence is notproperly completed within a predetermined time.If the device is used for alarm purposes only, itshould preferably be designated as 48A (alarm).

49. machine or transformer thermal relay isa relay that functions when the temperature of amachine armature or other load-carryingwinding or element of a machine or thetemperature of a power rectifier or powertransformer (including a power rectifiertransformer) exceeds a predetermined value.

46.

47.

49.


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50. instantaneous overcurrent relay. A relaythat functions instantaneously on an excessivevalue of current.

51. ac time overcurrent relay. A relay thatfunctions when the ac input current exceeds a

predetermined value, and in which the inputcurrent and operating time are inversely relatedthrough a substantial portion of the performancerange.

52. ac circuit breaker is a device that is usedto close and interrupt an ac power circuit undernormal conditions or to interrupt this circuitunder fault or emergency conditions.

55. power factor relay is a relay that operateswhen the power factor in an ac circuit rises

above or falls below a predetermined value.

56. field application relay is a relay thatautomatically controls the application of the fieldexcitation to an ac motor at somepredetermined point in the slip cycle.

59. overvoltage relay is a relay which operateswhen its input voltage is more than apredetermined value.

60. voltage or current balance relay is a relaythat operates on a given difference in voltage,

or current input or output, of two circuits.

62. time-delay stopping or opening relay isa time-delay relay that serves in conjunctionwith the device that initiates the shutdown,stopping, or opening operation in an automaticsequence or protective relay system.

50. ., .

51. ., ,

.

52.

55.

59. -

60.

62.

63. pressure switch is a switch which operateson given values, or on a given rate of change, ofpressure.

64. ground detector relay is a relay thatoperates on failure of machine or otherapparatus insulation to ground.NOTE: This function is not applied to a deviceconnected in the secondary circuit of currenttransformers in a normally grounded powersystem, where other device numbers with asuffix G or N should be used, that is, 51 N for anac time overcurrent relay connected in thesecondary neutral of the current transformers.

67. ac directional overcurrent relay is a relay

that functions on a desired value of acovercurrent flowing in a predetermineddirection.

68. blocking relay. relay that initiates a pilot

63.

67. (

)

68.


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signal for blocking of tripping on external faultsin a transmission line or in other apparatusunder predetermined conditions, or cooperateswith other devices to block tripping or to blockreclosing on an out-of-step condition or onpower swings.

74. alarm relay is a relay other than anannunciator, as covered under device function30, that is used to operate, or to operate inconnection with, a visual or audible alarm.

76. dc overcurrent relay is a relay thatfunctions when the current in a dc circuitexceeds a given value.

77. pulse transmitter is used to generate andtransmit pulses over a telemetering or pilot-wirecircuit to the remote indicating or receivingdevice.

78. phase-angle measuring or out-of-stepprotective relay is a relay that functions at apredetermined phase angle between twovoltages or between two currents or betweenvoltage and current.

79. ac reclosing relay is a relay that controlsthe automatic reclosing and locking out of an accircuit interrupter.

80. flow switch is a switch which operates ongiven values, or on a given rate of change, or

flow.

81. frequency relay is a relay that responds tothe frequency of an electrical quantity, operatingwhen the frequency or rate of change offrequency exceeds or is less than apredetermined value.

84. operating mechanism is the completeelectrical mechanism or servomechanism,including the operating motor, solenoids,position switches, etc, for a tap changer,induction regulator, or any similar piece of

apparatus which otherwise has no devicefunction number.

85. carrier or pilot-wire receiver relay is arelay that is operated or restrained by a signalused in connection with carrier-current or dcpilot-wire fault relaying.

86. lockout relay is a hand or electrically resetauxiliary relay that is operated upon theoccurrence of abnormal conditions to maintainassociated equipment or devices inoperativeuntil it is reset.

74.

76.

79.

81.

84. (.)

87. differential protective relay is a protectiverelay that functions on a percentage or phaseangle or other quantitative difference of two

87.


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currents or of some other electrical quantities.

90. regulating device is a device that functionsto regulate a quantity, or quantities, such asvoltage, current, power, speed, frequency,temperature, and load, at a certain value orbetween certain (generally close) limits formachines, tie lines, or other apparatus.

94. tripping or trip-free relay is a relay thatfunctions to trip a circuit breaker, contactor, orequipment, or to permit immediate tripping byother devices; or to prevent immediatereclosure of a circuit interrupter if it should openautomatically even though its closing circuit ismaintained closed.

95-99. Used only for specific applications inindividual installations where none of theassigned numbered functions from 1 to 94 aresuitable.

90. (.)

94. (.)

Suffix LettersSuffix letters may be used with device functionnumbers for various purposes. They permit amanifold multiplication of available functiondesignations for the large number and variety ofdevices used in the many types of equipmentcovered by this standard. They may also serveto denote individual or specific parts or auxiliarycontacts of these devices or certaindistinguishing features, characteristics, orconditions which describe the use of the device

or its contacts in the equipment.

A Alarm or auxiliary power

B Bus, or battery, or blower

BL Block (valve)

BP Bypass

BT Bus tie

C Capacitor, or condenser, or compensator,or carrier current, or coil

CC Closing coil

F Feeder of field or filament or filter or fan

G Generator or ground1)

H Heater or housing

L Line or logic

M Motor or metering

N Neutral1)

or network

Sl Seal-in

TC Trip coil

X Auxiliary relay

Y Auxiliary relay

Z Auxiliary relay1)

Suffix N is generally used in preference to Gfor devices connected in the secondary neutral

of current transformers, or in the secondary of acurrent transformer whose primary winding islocated in the neutral of a machine or powertransformer, except in the case of transmissionline relaying, where the suffix G is more


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commonly used for those relays that operate onground faults.

Other Suffix LettersA Accelerating or automaticB Blocking or backupC Close or coldE Emergency or engaged

F Failure or forwardH Hot or highHR Hand resetHS High speedL Left or local or low or lower or leadingM Manual0 OpenOFF OffON OnP PolarizingR Right or raise or reclosing or receiving or

remote or reverseS Sending or swing

T Test or trip or trailingTDC Time-delay closing

TDO Time-delay opening

U Up

All auxiliary contacts and position and limitswitches for such devices and equipment ascircuit breakers, contactors, valves andrheostats, and contacts of relays:a-Contact that is open when the main device is

in the standard reference position, commonly

referred to as the nonoperated ordeenergized position, and that closes whenthe device assumes the opposite position

b-Contact that is closed when the main deviceis in the standard reference position,commonly referred to as the nonoperated ordeenergized position, and that opens whenthe device assumes the opposite position

The simple designation a or b is used in allcases where there is no need to adjust thecontacts to change position at any particularpoint in the travel of the main device or where

the part of the travel where the contacts changeposition is of no significance in the control oroperating scheme.

23598960 relay symbols and device number ieec 37 (1)

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