Overview
The “Busbar differential protection” function detects busbar short circuits. It is stable in the event of external short-circuits with current-transformer saturation through intelligent saturation-detection methods, and is used for the single busbar.
For more detailed information on “Busbar differential 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 Busbar differential protection
| Addr. | Parameter | C | Setting Options | Default Setting |
| I-DIFF fast | ||||
| _:1 | I-DIFF unrestr:Mode | off on test |
off | |
| _:3 | I-DIFF unrestr:Threshold | 0.5 I/IrObj to 35.0 I/IrObj | 10.0 I/IrObj | |
| _:6 | I-DIFF unrestr:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
| _:100 | I-DIFF unrestr:Operate & flt.rec. blocked | no yes |
no | |
| I-DIFF unrestr | ||||
| _:1 | I-DIFF unrestr:Mode | off on test |
off | |
| _:3 | I-DIFF unrestr:Threshold | 0.5 I/IrObj to 35.0 I/IrObj | 10.0 I/IrObj | |
| _:6 | I-DIFF unrestr:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
| _:100 | I-DIFF unrestr:Operate & flt.rec. blocked | no yes |
no | |
| I-DIFF: General | ||||
| _:1 | I-DIFF:Mode | off on test |
off | |
| _:2 | I-DIFF:Operate & flt.rec. blocked | no yes |
no | |
| _:6 | I-DIFF:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
| I-DIFF: Operate curve | ||||
| _:3 | I-DIFF:Threshold | 0.05 I/IrObj to 2.00 I/IrObj | 0.20 I/IrObj | |
| _:100 | I-DIFF:Slope 1 | 0.00 to 0.80 | 0.30 | |
| _:101 | I-DIFF:Intersection 1 Irest | 0.00 I/IrObj to 5.00 I/IrObj | 0.67 I/IrObj | |
| _:102 | I-DIFF:Slope 2 | 0.25 to 0.95 | 0.70 | |
| _:103 | I-DIFF:Intersection 2 Irest | 1.00 I/IrObj to 20.00 I/IrObj | 2.50 I/IrObj | |
| I-DIFF: Starting detection | ||||
| _:106 | I-DIFF:Starting detection | no yes |
no | |
| _:107 | I-DIFF:Thresh. startup detection | 0.1 I/IrObj to 2.0 I/IrObj | 0.1 I/IrObj | |
| _:108 | I-DIFF:Factor increasing char. | 1.0 to 5.0 | 2.0 | |
| _:109 | I-DIFF:Max. perm. Start. time | 0.1 s to 180.0 s | 5.0 s | |
| I-DIFF: DC offset detection | ||||
| _:110 | I-DIFF:Factor increasing char. DC | 1.0 to 5.0 | 2.3 | |
| _:125 | I-DIFF:5th harmonics content | 10 % to 80 % | 30 % | |
| _:126 | I-DIFF:Crossblock. time 5th har. | 0.00 s to 200.00 s; ∞ | 0.00 s | |
| _:127 | I-DIFF:Limit Idiff 3., 5. harmonics | 0.5 I/IrObj to 20.0 I/IrObj | 1.5 I/IrObj | |
| I-DIFF: Ext. fault detection | ||||
| _:128 | I-DIFF:Threshold add-on stabiliz. | 1.00 I/IrObj to 20.00 I/IrObj | 2.00 I/IrObj | |
| _:129 | I-DIFF:Time of add-on stabiliz. | 0.00 s to 5.00 s; ∞ | 0.30 s | |
| _:130 | I-DIFF:Crossblk. time add-on st. | 0.00 s to 2.00 s; ∞ | 0.30 s | |
Logic Diagrams & highlights
Basic Principle of Differential Protection Using the Example of 2 Sides
Current Stabilization
Principle Current Course in External Short Circuit and Temporary Current-Transformer Saturation on One Side
Logic Diagram of the Differential Protection Function
Operate Curve of the Differential Protection Function
Amount Correction
Currents calculation
Pickup Characteristic of the Differential Protection
Increasing the Characteristic Curve after DC Detection
Logic DC Detection
Logic Startup Detection
Characteristic-Curve Increase at Startup
Trip Logic of I-DIFF
Instantaneous-Value Method calculations
I-DIFF Fast Characteristic Curve
Curve Plot for Internal Fault with Transformer Saturation (k= 0.65)
Curve Plot for External Fault with Transformer Saturation (k= 0.65)
Logic of the I-DIFF Fast Differential Protection Function
I-DIFF Unrestrained Characteristic Curve
Logic of the I-DIFF Unrestrained Differential Protection Function
Overall Trip Logic
Connection Example
