Overview
The “Underexcitation protection” function detects failures in the excitation (partial or complete failure) of synchronous machines. It responds to faulty voltage control (of the automatic voltage controller or done manually) during underexcited operation, and prevents asynchronous operation of synchronous machines and, therefore, a prohibited stress of the turbo-generator set.
For more detailed information on “Underexcitation 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 Stage with 3 Characteristic Curves
| Addr. | Parameter | C | Setting Options | Default Setting |
| General | ||||
| _:2311:103 | General:Threshold V1 min | 0.300 V to 200.000 V | 15.000 V | |
| _:2311:10 | General:Blk. by meas.- volt. failure | no yes |
yes | |
| Characteristic | ||||
| _:16531:1 | Characteristic:Mode | off on test |
off | |
| _:16531:2 | Characteristic:Operate & flt.rec. blocked | no yes |
no | |
| _:16531:3 | Characteristic:1/xd char- acteristic 1 | 0.10 to 5.00 | 0.70 | |
| _:16531:4 | Characteristic:Angle characteristic 1 | 50 ° to 120 ° | 70 ° | |
Setting parameters for Stage V Excitation <
| Addr. | Parameter | C | Setting Options | Default Setting |
| V excitation< | ||||
| _:1 | V excitation<:Mode | off on test |
off | |
| _:2 | V excitation<:Operate & flt.rec. blocked | no yes |
no | |
| _:4 | V excitation<:Vexc< | -110.000 V to 110.000 V | 0.000 V | |
| _:5 | V excitation<:Operate delay | 0.00 s to 60.00 s | 0.50 s | |
| _:101 | V excitation<:Sensor | MT fast 1.MT in 1 MT fast 1.MT in 2 MT fast 1.MT in 3 MT fast 1.MT in 4 none |
MT fast 1.MT in | |
Setting parameters for Stage with 1 Additional Characteristic Curves
| Addr. | Parameter | C | Setting Options | Default Setting |
| Add. char. # | ||||
| _:1 | Add. char. #:Mode | off on test |
off | |
| _:2 | Add. char. #:Operate & flt.rec. blocked | no yes |
no | |
| _:3 | Add. char. #:1/xd charac- teristic | 0.10 to 5.00 | 1.40 | |
| _:4 | Add. char. #:Angle char- acteristic | 50 ° to 120 ° | 90 ° | |
| _:5 | Add. char. #:Operate delay | 0.00 s to 60.00 s | 0.30 s | |
Logic Diagrams & highlights
Stabilization Limits of a Synchronous Machine
Capability-Diagram Display
Transformation of the Capability Diagram into an Admittance Diagram
Logic Diagram of the General Function Block
Logic Diagram of the Characteristic Curve Stage (Standard Stage)
Characteristic Curve of a Standard Stage
Operating Range of Synchronous and Asynchronous Machines
Connection Example
Generator Capability Diagram (Salient-Pole Machine)
Characteristic Curve 1 (Red) and Characteristic Curve 2 (Blue) Shown in the Per-Unit Diagram
Capability Diagram of a Cylindrical Rotor Synchronous Machine in the Per-Unit Diagram
Admittance Diagram of the Turbogenerator
Logic Diagram of Stage V Excitation<
Logic Diagram of the Stage Additional Characteristic Curve
