Overview
The “Generator differential protection” function detects short circuits in generators, and also ground faults in generators with a grounded neutral point (typical for low voltage).
For more detailed information on “Generator 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 Generator differential protection
Addr. | Parameter | C | Setting Options | Default Setting |
General | ||||
_:2311:100 | General:Meas. gnd. current side 1 | no yes |
no | |
_:2311:101 | General:Meas. gnd. current side 2 | no yes |
no | |
_:2311:102 | General:Meas. gnd. current side 3 | no yes |
no | |
_:2311:103 | General:Meas. gnd. current side 4 | no yes |
no | |
_:2311:104 | General:Meas. gnd. current side 5 | no yes |
no | |
_:2311:181 | General:Meas. gnd. curr. autosides | no with CT 1ph with CT 3ph |
no | |
_:2311:182 | General:Meas. gnd. curr. comp.side | no yes |
no | |
_:2311:105 | General:CT mismatch side 1 M3ph 1 | 0.000 to 100.000 | 0.000 | |
_:2311:106 | General:CT mismatch side 1 M3ph 2 | 0.000 to 100.000 | 0.000 | |
_:2311:107 | General:CT mismatch side 1 M3ph 3 | 0.000 to 100.000 | 0.000 | |
_:2311:108 | General:CT mismatch side 1 M3ph 4 | 0.000 to 100.000 | 0.000 | |
_:2311:109 | General:CT mismatch side 1 M1ph | 0.000 to 100.000 | 0.000 | |
_:2311:110 | General:CT mismatch side 2 M3ph 1 | 0.000 to 100.000 | 0.000 | |
_:2311:111 | General:CT mismatch side 2 M3ph 2 | 0.000 to 100.000 | 0.000 | |
_:2311:112 | General:CT mismatch side 2 M3ph 3 | 0.000 to 100.000 | 0.000 | |
_:2311:113 | General:CT mismatch side 2 M3ph 4 | 0.000 to 100.000 | 0.000 | |
_:2311:114 | General:CT mismatch side 2 M1ph | 0.000 to 100.000 | 0.000 | |
_:2311:115 | General:CT mismatch side 3 M3ph 1 | 0.000 to 100.000 | 0.000 | |
_:2311:116 | General:CT mismatch side 3 M3ph 2 | 0.000 to 100.000 | 0.000 | |
_:2311:117 | General:CT mismatch side 3 M3ph 3 | 0.000 to 100.000 | 0.000 | |
_:2311:118 | General:CT mismatch side 3 M3ph 4 | 0.000 to 100.000 | 0.000 | |
_:2311:119 | General:CT mismatch side 3 M1ph | 0.000 to 100.000 | 0.000 | |
_:2311:120 | General:CT mismatch side 4 M3ph 1 | 0.000 to 100.000 | 0.000 | |
_:2311:121 | General:CT mismatch side 4 M3ph 2 | 0.000 to 100.000 | 0.000 | |
_:2311:122 | General:CT mismatch side 4 M3ph 3 | 0.000 to 100.000 | 0.000 | |
_:2311:123 | General:CT mismatch side 4 M3ph 4 | 0.000 to 100.000 | 0.000 | |
_:2311:124 | General:CT mismatch side 4 M1ph | 0.000 to 100.000 | 0.000 | |
_:2311:125 | General:CT mismatch side 5 M3ph 1 | 0.000 to 100.000 | 0.000 | |
_:2311:126 | General:CT mismatch side 5 M3ph 2 | 0.000 to 100.000 | 0.000 | |
_:2311:127 | General:CT mismatch side 5 M3ph 3 | 0.000 to 100.000 | 0.000 | |
_:2311:128 | General:CT mismatch side 5 M3ph 4 | 0.000 to 100.000 | 0.000 | |
_:2311:129 | General:CT mismatch side 5 M1ph | 0.000 to 100.000 | 0.000 | |
_:2311:183 | General:CT mismatch M1ph | 0.000 to 100.000 | 0.000 | |
_:2311:130 | General:CT mismatch S1 M3ph 1 N | 0.000 to 100.000 | 0.000 | |
_:2311:131 | General:CT mismatch S1 M3ph 2 N | 0.000 to 100.000 | 0.000 | |
_:2311:132 | General:CT mismatch S1 M3ph 3 N | 0.000 to 100.000 | 0.000 | |
_:2311:133 | General:CT mismatch S1 M3ph 4 N | 0.000 to 100.000 | 0.000 | |
_:2311:134 | General:CT mismatch side 1 M1ph N | 0.000 to 100.000 | 0.000 | |
_:2311:176 | General:CT mismatch S2 M3ph 1 N | 0.000 to 100.000 | 0.000 | |
_:2311:135 | General:CT mismatch S2 M3ph 2 N | 0.000 to 100.000 | 0.000 | |
_:2311:136 | General:CT mismatch S2 M3ph 3 N | 0.000 to 100.000 | 0.000 | |
_:2311:137 | General:CT mismatch S2 M3ph 4 N | 0.000 to 100.000 | 0.000 | |
_:2311:177 | General:CT mismatch side 2 M1ph N | 0.000 to 100.000 | 0.000 | |
_:2311:138 | General:CT mismatch S3 M3ph 1 N | 0.000 to 100.000 | 0.000 | |
_:2311:139 | General:CT mismatch S3 M3ph 2 N | 0.000 to 100.000 | 0.000 | |
_:2311:140 | General:CT mismatch S3 M3ph 3 N | 0.000 to 100.000 | 0.000 | |
_:2311:141 | General:CT mismatch S3 M3ph 4 N | 0.000 to 100.000 | 0.000 | |
_:2311:178 | General:CT mismatch side 3 M1ph N | 0.000 to 100.000 | 0.000 | |
_:2311:142 | General:CT mismatch S4 M3ph 1 N | 0.000 to 100.000 | 0.000 | |
_:2311:143 | General:CT mismatch S4 M3ph 2 N | 0.000 to 100.000 | 0.000 | |
_:2311:144 | General:CT mismatch S4 M3ph 3 N | 0.000 to 100.000 | 0.000 | |
_:2311:145 | General:CT mismatch S4 M3ph 4 N | 0.000 to 100.000 | 0.000 | |
_:2311:179 | General:CT mismatch side 4 M1ph N | 0.000 to 100.000 | 0.000 | |
_:2311:146 | General:CT mismatch S5 M3ph 1 N | 0.000 to 100.000 | 0.000 | |
_:2311:147 | General:CT mismatch S5 M3ph 2 N | 0.000 to 100.000 | 0.000 | |
_:2311:148 | General:CT mismatch S5 M3ph 3 N | 0.000 to 100.000 | 0.000 | |
_:2311:149 | General:CT mismatch S5 M3ph 4 N | 0.000 to 100.000 | 0.000 | |
_:2311:180 | General:CT mismatch side 5 M1ph N | 0.000 to 100.000 | 0.000 | |
_:2311:184 | General:CT mismatch M1ph N | 0.000 to 100.000 | 0.000 | |
_:2311:191 | General:Reference side is | not assigned Side 1 Side 2 Side 3 Side 4 Side 5 |
not assigned | |
_:2311:151 | General:MU-ID Side 1 Mp3ph 1 |
0 to 100 | 0 | |
_:2311:152 | General:MU-ID Side 1 Mp3ph 2 |
0 to 100 | 0 | |
_:2311:153 | General:MU-ID Side 1 Mp3ph 3 |
0 to 100 | 0 | |
_:2311:154 | General:MU-ID Side 1 Mp3ph 4 |
0 to 100 | 0 | |
_:2311:155 | General:MU-ID Side 1 Mp1ph | 0 to 100 | 0 | |
_:2311:156 | General:MU-ID Side 2 Mp3ph 1 |
0 to 100 | 0 | |
_:2311:157 | General:MU-ID Side 2 Mp3ph 2 |
0 to 100 | 0 | |
_:2311:158 | General:MU-ID Side 2 Mp3ph 3 |
0 to 100 | 0 | |
_:2311:159 | General:MU-ID Side 2 Mp3ph 4 |
0 to 100 | 0 | |
_:2311:160 | General:MU-ID Side 2 Mp1ph | 0 to 100 | 0 | |
_:2311:161 | General:MU-ID Side 3 Mp3ph 1 |
0 to 100 | 0 | |
_:2311:162 | General:MU-ID Side 3 Mp3ph 2 |
0 to 100 | 0 | |
_:2311:163 | General:MU-ID Side 3 Mp3ph 3 |
0 to 100 | 0 | |
_:2311:164 | General:MU-ID Side 3 Mp3ph 4 |
0 to 100 | 0 | |
_:2311:165 | General:MU-ID Side 3 Mp1ph | 0 to 100 | 0 | |
_:2311:166 | General:MU-ID Side 4 Mp3ph 1 |
0 to 100 | 0 | |
_:2311:167 | General:MU-ID Side 4 Mp3ph 2 |
0 to 100 | 0 | |
_:2311:168 | General:MU-ID Side 4 Mp3ph 3 |
0 to 100 | 0 | |
_:2311:169 | General:MU-ID Side 4 Mp3ph 4 |
0 to 100 | 0 | |
_:2311:170 | General:MU-ID Side 4 Mp1ph | 0 to 100 | 0 | |
_:2311:171 | General:MU-ID Side 5 Mp3ph 1 |
0 to 100 | 0 | |
_:2311:172 | General:MU-ID Side 5 Mp3ph 2 |
0 to 100 | 0 | |
_:2311:173 | General:MU-ID Side 5 Mp3ph 3 |
0 to 100 | 0 | |
_:2311:174 | General:MU-ID Side 5 Mp3ph 4 |
0 to 100 | 0 | |
_:2311:175 | General:MU-ID Side 5 Mp1ph | 0 to 100 | 0 | |
_:2311:185 | General:MU-ID Mp1ph | 0 to 100 | 0 | |
_:2311:187 | General:Use tap-changer position | no yes |
yes | |
General | ||||
_:11041:1 | I-DIFF:Mode | off on test |
off | |
_:11041:2 | I-DIFF:Operate & flt.rec. blocked | no yes |
no | |
_:11041:6 | I-DIFF:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
Operate curve | ||||
_:11041:3 | I-DIFF:Threshold | 0.05 I/IrObj to 2.00 I/IrObj | 0.20 I/IrObj | |
_:11041:100 | I-DIFF:Slope 1 | 0.00 to 0.80 | 0.30 | |
_:11041:101 | I-DIFF:Intersection 1 Irest | 0.00 I/IrObj to 5.00 I/IrObj | 0.67 I/IrObj | |
_:11041:102 | I-DIFF:Slope 2 | 0.25 to 0.95 | 0.70 | |
_:11041:103 | I-DIFF:Intersection 2 Irest | 1.00 I/IrObj to 20.00 I/IrObj | 2.50 I/IrObj | |
Starting detection | ||||
_:11041:106 | I-DIFF:Starting detection | no yes |
yes | |
_:11041:107 | I-DIFF:Thresh. startup detection | 0.1 I/IrObj to 2.0 I/IrObj | 0.1 I/IrObj | |
_:11041:108 | I-DIFF:Factor increasing char. | 1.0 to 5.0 | 2.0 | |
_:11041:109 | I-DIFF:Max. perm. Start. time | 0.1 s to 180.0 s | 5.0 s | |
DC offset detection | ||||
_:11041:110 | I-DIFF:Factor increasing char. DC | 1.0 to 5.0 | 2.3 | |
Ext. fault detection | ||||
_:11041:128 | I-DIFF:Threshold add-on stabiliz. | 1.00 I/IrObj to 20.00 I/IrObj | 2.00 I/IrObj | |
_:11041:129 | I-DIFF:Time of add-on stabiliz. | 0.00 s to 5.00 s; ∞ | 0.30 s | |
_:11041:130 | I-DIFF:Crossblk. time add-on st. | 0.00 s to 2.00 s; ∞ | 0.30 s | |
I-DIFF fast | ||||
_:11071:1 | I-DIFF fast:Mode | off on test |
off | |
_:11071:3 | I-DIFF fast:Threshold | 0.5 I/IrObj to 35.0 I/IrObj | 7.5 I/IrObj | |
_:11071:6 | I-DIFF fast:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
_:11071:100 | I-DIFF fast:Operate & flt.rec. blocked | no yes |
no | |
I-DIFF unrestr | ||||
_:18002:1 | I-DIFF unrestr:Mode | off on test |
off | |
_:18002:3 | I-DIFF unrestr:Threshold | 0.5 I/IrObj to 35.0 I/IrObj | 10.0 I/IrObj | |
_:18002:6 | I-DIFF unrestr:Operate delay | 0.00 s to 60.00 s | 0.00 s | |
_:18002:100 | I-DIFF unrestr:Operate & flt.rec. blocked | no yes |
no | |
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

Calculation of differential protection currents

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

Operate current calculation

I-DIFF Unrestrained Characteristic Curve

Logic of the I-DIFF Unrestrained Differential Protection Function

Overall Trip Logic

Connection Example
