Overview
The “Stub differential protection” function is a selective, 2-step short-circuit protection for a line stub that can be tripped by a disconnector switch. It is important in 1 1/2 circuit-breaker layouts. It detects short circuits that lie between the current transformers and the feeder disconnector switch QB, operates strictly phase-segregated and permits 3-pole instantaneous high-speed tripping.
For more detailed information on “Stub differential protection” function, refer to SIPROTEC 5 devices, V8.30 & higher manuals.
To see other supported functions, click here.
Embedding the Stub Differential Protection
Setting Parameters
General setting parameters
| Addr. | Parameter | C | Setting Options | Default Setting |
| General | ||||
| _:2311:1 | General:Mode | off on test |
on | |
| S-DIFF | ||||
| _:8401:1 | S-DIFF:Mode | off on test |
on | |
| _:8401:2 | S-DIFF:Operate & flt.rec. blocked | no yes |
no | |
| _:8401:27 | S-DIFF:Blk. w. inrush curr. detect. | no yes |
no | |
| _:8401:3 | S-DIFF:Threshold | 1 A @ 100 Irated | 0.100 A to 20.000 A | 0.300 A |
| 5 A @ 100 Irated | 0.50 A to 100.00 A | 1.50 A | ||
| 1 A @ 50 Irated | 0.100 A to 20.000 A | 0.300 A | ||
| 5 A @ 50 Irated | 0.50 A to 100.00 A | 1.50 A | ||
| 1 A @ 1.6 Irated | 0.100 A to 20.000 A | 0.300 A | ||
| 5 A @ 1.6 Irated | 0.500 A to 100.000 A | 1.500 A | ||
| _:8401:6 | S-DIFF:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
Setting parameters for Stage S-DIFF Fast 2
| Addr. | Parameter | C | Setting Options | Default Setting |
| S-DIFF fast 2 | ||||
| _:18241:1 | S-DIFF fast 2:Mode | off on test |
on | |
| _:18241:2 | S-DIFF fast 2:Operate & flt.rec. blocked | no yes |
no | |
| _:18241:3 | S-DIFF fast 2:Threshold | 1 A @ 100 Irated | 0.500 A to 100.000 A | 1.000 A |
| 5 A @ 100 Irated | 2.50 A to 500.00 A | 5.00 A | ||
| 1 A @ 50 Irated | 0.500 A to 100.000 A | 1.000 A | ||
| 5 A @ 50 Irated | 2.50 A to 500.00 A | 5.00 A | ||
Setting parameters for Stage S-DIFF Fast
| Addr. | Parameter | C | Setting Options | Default Setting |
| S-DIFF fast | ||||
| _:8431:1 | S-DIFF fast:Mode | off on test |
on | |
| _:8431:2 | S-DIFF fast:Operate & flt.rec. blocked | no yes |
no | |
| _:8431:3 | S-DIFF fast:Threshold | 1 A @ 100 Irated | 0.800 A to 100.000 A | 1.000 A |
| 5 A @ 100 Irated | 4.00 A to 500.00 A | 5.00 A | ||
| 1 A @ 50 Irated | 0.800 A to 100.000 A | 1.000 A | ||
| 5 A @ 50 Irated | 4.00 A to 500.00 A | 5.00 A | ||
| 1 A @ 1.6 Irated | 0.800 A to 100.000 A | 1.000 A | ||
| 5 A @ 1.6 Irated | 4.000 A to 500.000 A | 5.000 A | ||
Logic Diagrams & highlights
Stub Differential Protection on a 1 1/2 Circuit-Breaker Layout
Operate Curve of the Stub-Differential Protection
Approximation of the Current-Transformer Errors
Pickup Characteristic of the S-DIFF Stage
Pickup Characteristic of the S-DIFF fast 2 Stage
Output Logic
