ST9C
Exc IEEE ST9C model
This article is incomplete, some sections must be written.
Context
This voltage regulator model first appeared in the IEEE Std 421.5-2016 (of Electrical & Engineers, 2016). It has been reproduced identically in the IEC 61970-302:2024 version (Commission, 2024).
Model use, assumptions, validity domain and limitations
To be completed
Model inputs and output
The input variables are :
| Variable | Description | Units |
|---|---|---|
| IrPu | rotor current | pu (base SNom, user-selected base voltage) |
| itPu | complex current at the terminal | pu (base SNom, UNom) |
| UsPu | measured stator voltage | pu (base UNom) |
| UsRefPu | reference stator voltage | pu (base UNom) |
| utPu | complex voltage at the terminal | pu (base UNom) |
| UOelPu (optional) | output voltage of overexcitation limiter | pu (base UNom) |
| UPssPu (optional) | output voltage of power system stabilizer | pu (base UNom) |
| USclOelPu (optional) | output voltage of stator current overexcitation limiter | pu (base UNom) |
| USclUelPu (optional) | output voltage of stator current underexcitation limiter | pu (base UNom) |
| UUelPu (optional) | output voltage of underexcitation limiter | pu (base UNom) |
The output signal is EfdPu, the excitation voltage in pu (user-selected base voltage).
Model parameters
| Parameter | Description | Units |
|---|---|---|
| Ka | Voltage regulator gain | pu |
| Kas | Power converter gain proportional to supply voltage, | pu |
| Kc | Rectifier loading factor proportional to commutating reactance, | pu |
| Ki | Potential circuit (current) gain coefficient | pu |
| Kp | Potential circuit gain | pu |
| Ku | Gain associated with activation of takeover UEL, | pu |
| PositionOel | Input location : (0) none, (1) voltage error summation, (2) take-over | - |
| PositionScl | Input location : (0) none, (1) voltage error summation, (2) take-over | - |
| PositionUel | Input location : (0) none, (1) voltage error summation, (2) take-over | - |
| Sw1 | If true, power source derived from terminal voltage, if false, independent from terminal voltage | - |
| tA | Voltage regulator time constant | s |
| tAs | Equivalent time constant of power converter firing control | s |
| tAUel | Time constant of underexcitation limiter | s |
| tBd | Filter time constant of differential part of voltage regulator | s |
| tCd | Time constant of differential part of voltage regulator | s |
| Thetap | Potential circuit phase angle | rad |
| tR | Stator voltage filter time constant | s |
| VaMaxPu | Maximum output voltage of limited first order | pu |
| VaMinPu | Minimum output voltage of limited first order | pu |
| VbMaxPu | Maximum available exciter field voltage | pu (base UNom) |
| VrMaxPu | Maximum field voltage | pu (user-selected base voltage) |
| VrMinPu | Minimum field voltage | pu (user-selected base voltage) |
| XlPu | Reactance associated with potential source | pu (base SNom, UNom) |
| ZaPu | Dead-band for differential part influence on voltage regulator | pu (base UNom) |
Model diagram
Open source implementations
This model has been successfully implemented in :
| Software | URL | Language | Open-Source License | Last consulted date | Comments |
|---|---|---|---|---|---|
| Dynawo | Link | Modelica | MPL v2.0 | 24/05/2024 |
References
- of Electrical, T. I., & Engineers, E. (2016). IEEE recommended practice for excitation system models for power system stability studies . IEEE Std 421.5-2016. https://home.engineering.iastate.edu/ jdm/ee554/IEEEstd421.5-2016RecPracExSysModsPwrSysStabStudies.pdf
- Commission, I. E. (2024). Energy management system application program interface (EMS-API) Part 302: Common information model (CIM) dynamics. IEC 61970-302. https://webstore.iec.ch/preview/info_iec61970-302%7Bed2.0%7Db.pdf