Saturday, July 28, 2012

Power System Device Function Numbers


IEEE                   Device No. Protection Function

2                         Time-delay relay

12                       Overspeed

13                       Synchronous speed check or centrifugal switch

14                       Underspeed device

21                       Impedance relay

23, 23Q              Temperature-control device, Oil temperature monitor

24                       V/Hz over fluxing relay

26, 26W              Apparatus overheating device, Winding temperature monitor

27                      Undervoltage — instantaneous or inverse

32                      Directional power relay

38                      Bearing temperature monitor

39                     Vibration monitor

40                     Loss of field protection

41                     Field contactor or circuit breaker

46                    Phase-balance or negative-sequence relay

47                    Phase-sequence undervoltage

48                    Incomplete-sequence relay

49                    Thermal relay operated by current or winding temperature

50, 50G            Instantaneous OC relay phase, Instantaneous OC relay, ground

51, 51G            Time OC relay, phase, Time OC relay, ground

51N                   Residual connected TOC

52                      Power circuit breaker

53                      Excitation check relay for synchronous motors

55                      Power factor relay

56                      Field application relay

59, 59GN          Overvoltage relay, Stator ground relay (HR)

60                     Voltage balance relay

63                     Liquid or gas pressure relay

64                     Ground-fault detection from machine to ground

71                     Liquid or gas level relay

78                     Out-of-step relay

81                     Frequency relay

86                      Lockout relay

87, 87N             Differential-protection relay, phase, Differential-    protection relay, ground

94                      Tripping or trip-free relay
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