Protection function |
ANSI |
Three-phase overcurrent protection INST,DT or IDMT - I> ... I>>>> |
50/51_1..._4 |
Residual overcurrent protection INST, DT or IDMT - I0> ... I0>>>> |
50/51N(S)_1...4 |
Harmonic overcurrent protection / inrush blocking INST, DT or IDMT - Ixh > ... Ixh >>>> |
50/51h/68h |
Cold load pick-up block - CLPU |
68 |
Current unbalance / broken conductor protection INST, DT or IDMT - I2 (I/I1)>...I2 (I/I1)>>>> |
46/46R/46L |
Low or high-impedance restricted earth-fault / cable end differential protection - I0d> |
87N |
Motor thermal overload protection - T > |
49M |
Motor start-up supervision / locked rotor protection - Ist> |
48, 14 |
Frequent start supervision - N> |
66 |
Undercurrent / loss of load protection - I< |
37 |
Mechanical jam protection - Im> |
51m |
CT supervision - CTS |
|
Breaker failure protection - CBFP |
50BF/52BF |