Overview
The “Overexcitation protection” function is used for detecting high induction values in generators and transformers. It protects the equipment from excessive thermal loads. The induction is recorded indirectly by analyzing the V/f ratio (also referred to as Volt per Hertz protection).
For more detailed information on “Overexcitation 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 Overexcitation Protection
Addr. | Parameter | C | Setting Options | Default Setting |
Definite-T 1 | ||||
_:13621:1 | Definite-T 1:Mode | off on test |
off | |
_:13621:2 | Definite-T 1:Operate & flt.rec. blocked | no yes |
no | |
_:13621:3 | Definite-T 1:Threshold | 1.00 to 1.40 | 1.40 | |
_:13621:6 | Definite-T 1:Operate delay | 0.00 s to 60.00 s | 1.00 s | |
Therm.charact. | ||||
_:13591:1 | Therm.charact.:Mode | off on test |
off | |
_:13591:2 | Therm.charact.:Operate & flt.rec. blocked | no yes |
no | |
_:13591:3 | Therm.charact.:Threshol d | 1.00 to 1.20 | 1.10 | |
_:13591:101 | Therm.charact.:Warning delay | 0.00 s to 60.00 s | 10.00 s | |
_:13591:102 | Therm.charact.:Cooling time therm.replica | 0 s to 100 000 s | 3600 s | |
Logic Diagrams & highlights
Logic of the Overexcitation Protection with Thermal Characteristic Curve

V/f Method of Measurement

Tripping Zone of the Thermal Characteristic Curve (I)

Tripping Zone of the Thermal Characteristic Curve (II)

Logic of the Overexcitation Protection with Independent Characteristic Curve (Definite-Time Stage)
