Protection Function |
ANSI |
|
|
Protection Function |
ANSI |
Generator differential protection - 3IdG> |
87G |
|
|
Definite time overvoltage protection - U >, U >> |
59 |
Three-phase instantaneous overcurrent protection - >>> |
50 |
|
|
Definite time undervoltage protection - U |
27 |
Three-phase time overcurrent protection - I>, I>> |
51 |
|
|
Residual voltage protection - Uo >, Uo>> |
59N |
Residual instantaneous overcurrent protection - Io>>> |
50N |
|
|
Overfrequency protection - f >, f >> |
81O |
Residual instantaneous overcurrent protection - Io>>> |
51N |
|
|
Underfrequency protection - f |
81U |
Voltage restrained or voltage controlled overcurren - Iv> |
51V |
|
|
Rate of change of frequency protection - df/dt |
81R |
Directional three-phase overcurrent protection - IDir>,IDir >> |
67 |
|
|
Synchrocheck - SYNC |
25 |
Directional residual overcurrent protection - IoDir>,IoDir >> |
67N |
|
|
Reverse power/directional overpower protection |
32 |
Underimpedance protection, Z< |
21 |
|
|
Directional underpower protection |
32 |
Inrush detection and blocking - I2h > |
68 |
|
|
Fuse failure - VTS |
60 |
Current unbalance protection - Iub > |
60 |
|
|
Loss of field - X< |
40 |
Negative sequence overcurrent - I2 |
46 |
|
|
Overexcitation/volts per hertz, V/Hz |
24 |
Thermal protection - T > |
49 |
|
|
Breaker failure protection - CBFP |
50BF |