ANSI IEC Comparison

ANSI IEC 60617 Description

21FL FLOC Fault locator

21G Z< Underimpedance

24 U/f> Overexcitation

25 SYNC Synchronisation check

27 U< Undervoltage

32 P→Directional power relay    32P, P→, - active power    32Q, Q→ - reactive powerpower

37 I< Non-directional undercurrent

40 X< Underexcitation

46 I2> Negative-phase sequence

47 U2> Phase-sequence voltage protection

48, 14, 66 Is²t,n< Start-up supervision for motors

49F Ith> Thermal protection for cables

49M/49G/49TThree-phase thermal protection for machines    M - motor, G - generators, T - transformer

50N/51N I0> Non-directional earth-fault

51 I>Non-directional overcurrent    51C, I> - shunt capacitors    51V, I(U)> - voltage dependant

59 U>Overvoltage    59N, U0> - residual overvoltage

67 I>→Directional overcurrent    67N, I0>→ - directional earth-fault

68 I2> Transformer/motor inrush current

79 0→1 Auto-reclosure

81 fFrequency relay    81N, f< - underfrquency    81O, f> - overfrequency

87 ΔI>

Differential protection    87G, ΔI> - generator    87M, ΔI> - motor    87T, ΔI> - transformer    87N, ΔI0> - restricted earth fault

Notes:      1. for high set and instantaneous tripping, '>' can be replaced with '>>' or '>>'      2. '3' can be placed before designations to indicate three phase, i.e. 3I<

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