Overview
The “Underfrequency protection” function is used to detect underfrequencies in electrical power systems or machines, monitor the frequency band and output failure indications, decouple power systems, load shedding to ensure power system stability and protect motors, and disconnect generating units when the power system frequency is critical (for example, f < 0.95 frated).
For more detailed information on “Underfrequency protection” function, refer to SIPROTEC 5 devices, V8.30 & higher manuals.
To see other supported functions, click here.
Structure/Embedding of the Function
Setting Parameters
Setting parameters for Underfrequency protection
| Addr. | Parameter | C | Setting Options | Default Setting |
| General | ||||
| _:2311:101 | General:Minimum voltage | 3.000 V to 175.000 V | 37.500 V | |
| _:2311:109 | General:Dropout differ- ential | 20 mHz to 2000 mHz | 20 mHz | |
| Stage 1 | ||||
| _:61:1 | Stage 1:Mode | off on test |
off | |
| _:61:2 | Stage 1:Operate & flt.rec. blocked | no yes |
no | |
| _:61:3 | Stage 1:Threshold | 30.00 Hz to 70.00 Hz | 49.80 Hz | |
| _:61:6 | Stage 1:Operate delay | 0.00 s to 600.00 s | 10.00 s | |
| Stage 2 | ||||
| _:62:1 | Stage 2:Mode | off on test |
off | |
| _:62:2 | Stage 2:Operate & flt.rec. blocked | no yes |
no | |
| _:62:3 | Stage 2:Threshold | 30.00 Hz to 70.00 Hz | 47.50 Hz | |
| _:62:6 | Stage 2:Operate delay | 0.00 s to 600.00 s | 10.00 s | |
| Stage 3 | ||||
| _:63:1 | Stage 3:Mode | off on test |
off | |
| _:63:2 | Stage 3:Operate & flt.rec. blocked | no yes |
no | |
| _:63:3 | Stage 3:Threshold | 30.00 Hz to 70.00 Hz | 47.00 Hz | |
| _:63:6 | Stage 3:Operate delay | 0.00 s to 600.00 s | 10.00 s | |
Logic Diagrams & highlights
Logic Diagram of the Underfrequency-Protection Stage
