Overview
Overfrequency occurs because of sudden load drops or shunt faults in the power network. Close to the generating plant, generator governor problems can also cause over frequency. “Overfrequency protection (SAPTOF)” function measures frequency with high accuracy, and is used mainly for generation shedding
and remedial action schemes. It is also used as a frequency stage initiating load restoring. A definite time delay is provided for operate.
For more detailed information on “Overfrequency protection (SAPTOF)”, refer to ABB, Relion 670 Series manuals.
To see other supported functions, click here.
Function Identification
| Function description | IEC 61850 identification |
IEC 60617 identification |
ANSI/IEEE C37.2 device number |
| Overfrequency protection | SAPTOF | f > | 81 |
Signals & Setting Parameters
SAPTOF function block
SAPTOF Input signals
| SAPTOF Input signals | |||
| Name | Type | Default | Description |
| U3P | GROUP SIGNAL | – | Three phase group signal for voltage inputs |
| BLOCK | BOOLEAN | 0 | Block of function |
| BLKTRIP | BOOLEAN | 0 | Blocking operate output |
SAPTOF Output signals
| SAPTOF Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | General trip signal | |
| START | BOOLEAN | General start signal | |
| BLKDMAGN | BOOLEAN | Blocking indication due to low amplitude | |
| FREQ | REAL | Measured frequency | |
SAPTOF Group settings (basic)
| SAPTOF Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| StartFrequency | 35.00 – 90.00 | Hz | 0.01 | 51.20 | Frequency set value |
| IntBlockLevel | 0.0 – 100.0 | %UB | 1.0 | 50.0 | Internal blocking level in % of UBase |
| tDelay | 0.000 – 60.000 | s | 0.001 | 0.000 | Operate time delay |
| tReset | 0.000 – 60.000 | s | 0.001 | 0.000 | Time delay for reset |
SAPTOF Non group settings (basic)
| SAPTOF Non group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| GlobalBaseSel | 1 – 12 | – | 1 | 1 | Selection of one of the Global Base Value groups |
Logics & highlights
Simplified logic diagram for SAPTOF
