ST1C
Exc IEEE ST1C 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). In previous standard versions (1992, 2005), its predecessor model was called ST1A. Compared to ST1A, ST1C has additional options for connecting OEL input.
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) |
| UsPu | measured stator voltage | pu (base UNom) |
| UsRefPu | reference stator voltage | 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 |
|---|---|---|
| IlrPu | Exciter output current limit reference | pu (base SNom, user-selected base voltage) |
| Ka | Voltage regulator gain | pu |
| Kc | Rectifier loading factor proportional to commutating reactance, | pu |
| Kf | Exciter rate feedback gain | pu |
| Klr | Gain of field current limiter | pu |
| PositionOel | Input location : (0) none, (1) voltage error summation, (2) take-over at AVR input, (3) take-over at AVR output | - |
| PositionPss | Input location : (0) none, (1) voltage error summation, (2) summation at AVR output | - |
| PositionScl | Input location : (0) none, (1) voltage error summation, (2) take-over at AVR input, (3) take-over at AVR output | - |
| PositionUel | Input location : (0) none, (1) voltage error summation, (2) take-over at AVR input, (3) take-over at AVR output | - |
| tA | Voltage regulator time constant | s |
| tB | Voltage regulator lag time constant | s |
| tB1 | Voltage regulator second lag time constant | s |
| tC | Voltage regulator lead time constant | s |
| tC1 | Voltage regulator second lead time constant | s |
| tF | Exciter rate feedback time constant | s |
| tR | Stator voltage filter time constant | s |
| VaMaxPu | Maximum output voltage of voltage regulator | pu (user-selected base voltage) |
| VaMinPu | Minimum output voltage of voltage regulator | pu (user-selected base voltage) |
| ViMaxPu | Maximum input voltage of voltage regulator | pu (user-selected base voltage) |
| ViMinPu | Minimum input voltage of voltage regulator | pu (user-selected base voltage) |
| VrMaxPu | Maximum field voltage | pu (user-selected base voltage) |
| VrMinPu | Minimum field voltage | pu (user-selected base voltage) |
Model diagram
Model variant
In the ST1A model :
- the overexcitation limiter voltage is applied at the AVR output
- there is no stator current limiter
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