Overview
The “Rate-of-change of frequency protection (SAPFRC)” function gives an early indication of a main disturbance in the system. SAPFRC measures frequency with high accuracy, and can be used for generation shedding, load shedding and remedial action schemes. SAPFRC can discriminate between a positive or negative change of frequency. A definite time delay is provided for operate.
For more detailed information on “Rate-of-change of frequency protection (SAPFRC)” function, 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 |
| Rate-of-change of frequency protection | SAPFRC | df/dt >< | 81 |
Signals & Setting Parameters
SAPFRC function block
SAPFRC Input signals
| SAPFRC 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 |
| BLKREST | BOOLEAN | 0 | Blocking restore output |
SAPFRC Output signals
| SAPFRC Output signals | |||
| Name | Type | Description | |
| TRIP | BOOLEAN | Trip signal | |
| START | BOOLEAN | Start signal | |
| RESTORE | BOOLEAN | Restore signal for load restoring purposes | |
| BLKDMAGN | BOOLEAN | Blocking indication due to low amplitude | |
SAPFRC Group settings (basic)
| SAPFRC Group settings (basic) | |||||
| Name | Values (Range) | Unit | Step | Default | Description |
| Operation | Off On |
– | – | Off | Operation Off / On |
| StartFreqGrad | -10.00 – 10.00 | Hz/s | 0.01 | 0.50 | Frequency gradient start value, the sign defines direction |
| IntBlockLevel | 0.0 – 100.0 | %UB | 1.0 | 50.0 | Internal blocking level in % of UBase |
| tDelay | 0.000 – 60.000 | s | 0.001 | 0.200 | Operate time delay |
| RestoreFreq | 45.00 – 65.00 | Hz | 0.01 | 49.90 | Restore frequency value |
| tRestore | 0.000 – 60.000 | s | 0.001 | 0.000 | Restore time delay |
| tReset | 0.000 – 60.000 | s | 0.001 | 0.000 | Time delay for reset |
SAPFRC Non group settings (basic)
| SAPFRC 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 SAPFRC
